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[PATCH 00/23] slab+slub accounting for memcg [message #45989] Fri, 20 April 2012 21:57 Go to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
Hi,

This is my current attempt at getting the kmem controller
into a mergeable state. IMHO, all the important bits are there, and it should't
change *that* much from now on. I am, however, expecting at least a couple more
interactions before we sort all the edges out.

This series works for both the slub and the slab. One of my main goals was to
make sure that the interfaces we are creating actually makes sense for both
allocators.

I did some adaptations to the slab-specific patches, but the bulk of it
comes from Suleiman's patches. I did the best to use his patches
as-is where possible so to keep authorship information. When not possible,
I tried to be fair and quote it in the commit message.

In this series, all existing caches are created per-memcg after its first hit.
The main reason is, during discussions in the memory summit we came into
agreement that the fragmentation problems that could arise from creating all
of them are mitigated by the typically small quantity of caches in the system
(order of a few megabytes total for sparsely used caches).
The lazy creation from Suleiman is kept, although a bit modified. For instance,
I now use a locked scheme instead of cmpxcgh to make sure cache creation won't
fail due to duplicates, which simplifies things by quite a bit.

The slub is a bit more complex than what I came up with in my slub-only
series. The reason is we did not need to use the cache-selection logic
in the allocator itself - it was done by the cache users. But since now
we are lazy creating all caches, this is simply no longer doable.

I am leaving destruction of caches out of the series, although most
of the infrastructure for that is here, since we did it in earlier
series. This is basically because right now Kame is reworking it for
user memcg, and I like the new proposed behavior a lot more. We all seemed
to have agreed that reclaim is an interesting problem by itself, and
is not included in this already too complicated series. Please note
that this is still marked as experimental, so we have so room. A proper
shrinker implementation is a hard requirement to take the kmem controller
out of the experimental state.

I am also not including documentation, but it should only be a matter
of merging what we already wrote in earlier series plus some additions.

Glauber Costa (19):
slub: don't create a copy of the name string in kmem_cache_create
slub: always get the cache from its page in kfree
slab: rename gfpflags to allocflags
slab: use obj_size field of struct kmem_cache when not debugging
change defines to an enum
don't force return value checking in res_counter_charge_nofail
kmem slab accounting basic infrastructure
slab/slub: struct memcg_params
slub: consider a memcg parameter in kmem_create_cache
slab: pass memcg parameter to kmem_cache_create
slub: create duplicate cache
slub: provide kmalloc_no_account
slab: create duplicate cache
slab: provide kmalloc_no_account
kmem controller charge/uncharge infrastructure
slub: charge allocation to a memcg
slab: per-memcg accounting of slab caches
memcg: disable kmem code when not in use.
slub: create slabinfo file for memcg

Suleiman Souhlal (4):
memcg: Make it possible to use the stock for more than one page.
memcg: Reclaim when more than one page needed.
memcg: Track all the memcg children of a kmem_cache.
memcg: Per-memcg memory.kmem.slabinfo file.

include/linux/memcontrol.h | 87 ++++++
include/linux/res_counter.h | 2 +-
include/linux/slab.h | 26 ++
include/linux/slab_def.h | 77 ++++++-
include/linux/slub_def.h | 36 +++-
init/Kconfig | 2 +-
mm/memcontrol.c | 607 +++++++++++++++++++++++++++++++++++++++++--
mm/slab.c | 390 +++++++++++++++++++++++-----
mm/slub.c | 255 ++++++++++++++++--
9 files changed, 1364 insertions(+), 118 deletions(-)

--
1.7.7.6
[PATCH 02/23] slub: always get the cache from its page in kfree [message #45990 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
struct page already have this information. If we start chaining
caches, this information will always be more trustworthy than
whatever is passed into the function

Signed-off-by: Glauber Costa <glommer@parallels.com>
---
mm/slub.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index af8cee9..2652e7c 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2600,7 +2600,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)

page = virt_to_head_page(x);

- slab_free(s, page, x, _RET_IP_);
+ slab_free(page->slab, page, x, _RET_IP_);

trace_kmem_cache_free(_RET_IP_, x);
}
--
1.7.7.6
[PATCH 04/23] memcg: Make it possible to use the stock for more than one page. [message #45991 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
From: Suleiman Souhlal <ssouhlal@FreeBSD.org>

Signed-off-by: Suleiman Souhlal <suleiman@google.com>
---
mm/memcontrol.c | 18 +++++++++---------
1 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 932a734..4b94b2d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1998,19 +1998,19 @@ static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
static DEFINE_MUTEX(percpu_charge_mutex);

/*
- * Try to consume stocked charge on this cpu. If success, one page is consumed
- * from local stock and true is returned. If the stock is 0 or charges from a
- * cgroup which is not current target, returns false. This stock will be
- * refilled.
+ * Try to consume stocked charge on this cpu. If success, nr_pages pages are
+ * consumed from local stock and true is returned. If the stock is 0 or
+ * charges from a cgroup which is not current target, returns false.
+ * This stock will be refilled.
*/
-static bool consume_stock(struct mem_cgroup *memcg)
+static bool consume_stock(struct mem_cgroup *memcg, int nr_pages)
{
struct memcg_stock_pcp *stock;
bool ret = true;

stock = &get_cpu_var(memcg_stock);
- if (memcg == stock->cached && stock->nr_pages)
- stock->nr_pages--;
+ if (memcg == stock->cached && stock->nr_pages >= nr_pages)
+ stock->nr_pages -= nr_pages;
else /* need to call res_counter_charge */
ret = false;
put_cpu_var(memcg_stock);
@@ -2309,7 +2309,7 @@ again:
VM_BUG_ON(css_is_removed(&memcg->css));
if (mem_cgroup_is_root(memcg))
goto done;
- if (nr_pages == 1 && consume_stock(memcg))
+ if (consume_stock(memcg, nr_pages))
goto done;
css_get(&memcg->css);
} else {
@@ -2334,7 +2334,7 @@ again:
rcu_read_unlock();
goto done;
}
- if (nr_pages == 1 && consume_stock(memcg)) {
+ if (consume_stock(memcg, nr_pages)) {
/*
* It seems dagerous to access memcg without css_get().
* But considering how consume_stok works, it's not
--
1.7.7.6
[PATCH 03/23] slab: rename gfpflags to allocflags [message #45992 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
A consistent name with slub saves us an acessor function.
In both caches, this field represents the same thing. We would
like to use it from the mem_cgroup code.

Signed-off-by: Glauber Costa <glommer@parallels.com>
---
include/linux/slab_def.h | 2 +-
mm/slab.c | 10 +++++-----
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index fbd1117..d41effe 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -39,7 +39,7 @@ struct kmem_cache {
unsigned int gfporder;

/* force GFP flags, e.g. GFP_DMA */
- gfp_t gfpflags;
+ gfp_t allocflags;

size_t colour; /* cache colouring range */
unsigned int colour_off; /* colour offset */
diff --git a/mm/slab.c b/mm/slab.c
index e901a36..c6e5ab8 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1798,7 +1798,7 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
flags |= __GFP_COMP;
#endif

- flags |= cachep->gfpflags;
+ flags |= cachep->allocflags;
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
flags |= __GFP_RECLAIMABLE;

@@ -2508,9 +2508,9 @@ kmem_cache_create (const char *name, size_t size, size_t align,
cachep->colour = left_over / cachep->colour_off;
cachep->slab_size = slab_size;
cachep->flags = flags;
- cachep->gfpflags = 0;
+ cachep->allocflags = 0;
if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
- cachep->gfpflags |= GFP_DMA;
+ cachep->allocflags |= GFP_DMA;
cachep->buffer_size = size;
cachep->reciprocal_buffer_size = reciprocal_value(size);

@@ -2857,9 +2857,9 @@ static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
{
if (CONFIG_ZONE_DMA_FLAG) {
if (flags & GFP_DMA)
- BUG_ON(!(cachep->gfpflags & GFP_DMA));
+ BUG_ON(!(cachep->allocflags & GFP_DMA));
else
- BUG_ON(cachep->gfpflags & GFP_DMA);
+ BUG_ON(cachep->allocflags & GFP_DMA);
}
}

--
1.7.7.6
[PATCH 07/23] change defines to an enum [message #45993 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
This is just a cleanup patch for clarity of expression.
In earlier submissions, people asked it to be in a separate
patch, so here it is.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
---
mm/memcontrol.c | 9 ++++++---
1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index cbffc4c..2810228 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -374,9 +374,12 @@ enum charge_type {
};

/* for encoding cft->private value on file */
-#define _MEM (0)
-#define _MEMSWAP (1)
-#define _OOM_TYPE (2)
+enum res_type {
+ _MEM,
+ _MEMSWAP,
+ _OOM_TYPE,
+};
+
#define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
#define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff)
#define MEMFILE_ATTR(val) ((val) & 0xffff)
--
1.7.7.6
[PATCH 05/23] memcg: Reclaim when more than one page needed. [message #45994 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
From: Suleiman Souhlal <ssouhlal@FreeBSD.org>

mem_cgroup_do_charge() was written before slab accounting, and expects
three cases: being called for 1 page, being called for a stock of 32 pages,
or being called for a hugepage. If we call for 2 pages (and several slabs
used in process creation are such, at least with the debug options I had),
it assumed it's being called for stock and just retried without reclaiming.

Fix that by passing down a minsize argument in addition to the csize.

And what to do about that (csize == PAGE_SIZE && ret) retry? If it's
needed at all (and presumably is since it's there, perhaps to handle
races), then it should be extended to more than PAGE_SIZE, yet how far?
And should there be a retry count limit, of what? For now retry up to
COSTLY_ORDER (as page_alloc.c does), stay safe with a cond_resched(),
and make sure not to do it if __GFP_NORETRY.

Signed-off-by: Suleiman Souhlal <suleiman@google.com>
---
mm/memcontrol.c | 18 +++++++++++-------
1 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4b94b2d..cbffc4c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2187,7 +2187,8 @@ enum {
};

static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
- unsigned int nr_pages, bool oom_check)
+ unsigned int nr_pages, unsigned int min_pages,
+ bool oom_check)
{
unsigned long csize = nr_pages * PAGE_SIZE;
struct mem_cgroup *mem_over_limit;
@@ -2210,18 +2211,18 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
} else
mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
/*
- * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
- * of regular pages (CHARGE_BATCH), or a single regular page (1).
- *
* Never reclaim on behalf of optional batching, retry with a
* single page instead.
*/
- if (nr_pages == CHARGE_BATCH)
+ if (nr_pages > min_pages)
return CHARGE_RETRY;

if (!(gfp_mask & __GFP_WAIT))
return CHARGE_WOULDBLOCK;

+ if (gfp_mask & __GFP_NORETRY)
+ return CHARGE_NOMEM;
+
ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
return CHARGE_RETRY;
@@ -2234,8 +2235,10 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
* unlikely to succeed so close to the limit, and we fall back
* to regular pages anyway in case of failure.
*/
- if (nr_pages == 1 && ret)
+ if (nr_pages <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER) && ret) {
+ cond_resched();
return CHARGE_RETRY;
+ }

/*
* At task move, charge accounts can be doubly counted. So, it's
@@ -2369,7 +2372,8 @@ again:
nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
}

- ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, oom_check);
+ ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, nr_pages,
+ oom_check);
switch (ret) {
case CHARGE_OK:
break;
--
1.7.7.6
[PATCH 09/23] kmem slab accounting basic infrastructure [message #45995 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
This patch adds the basic infrastructure for the accounting of the slab
caches. To control that, the following files are created:

* memory.kmem.usage_in_bytes
* memory.kmem.limit_in_bytes
* memory.kmem.failcnt
* memory.kmem.max_usage_in_bytes

They have the same meaning of their user memory counterparts. They reflect
the state of the "kmem" res_counter.

The code is not enabled until a limit is set. This can be tested by the flag
"kmem_accounted". This means that after the patch is applied, no behavioral
changes exists for whoever is still using memcg to control their memory usage.

We always account to both user and kernel resource_counters. This effectively
means that an independent kernel limit is in place when the limit is set
to a lower value than the user memory. A equal or higher value means that the
user limit will always hit first, meaning that kmem is effectively unlimited.

People who want to track kernel memory but not limit it, can set this limit
to a very high number (like RESOURCE_MAX - 1page - that no one will ever hit,
or equal to the user memory)

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
---
mm/memcontrol.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 79 insertions(+), 1 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2810228..36f1e6b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -252,6 +252,10 @@ struct mem_cgroup {
};

/*
+ * the counter to account for kernel memory usage.
+ */
+ struct res_counter kmem;
+ /*
* Per cgroup active and inactive list, similar to the
* per zone LRU lists.
*/
@@ -266,6 +270,7 @@ struct mem_cgroup {
* Should the accounting and control be hierarchical, per subtree?
*/
bool use_hierarchy;
+ bool kmem_accounted;

bool oom_lock;
atomic_t under_oom;
@@ -378,6 +383,7 @@ enum res_type {
_MEM,
_MEMSWAP,
_OOM_TYPE,
+ _KMEM,
};

#define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
@@ -1470,6 +1476,10 @@ done:
res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
+ printk(KERN_INFO "kmem: usage %llukB, limit %llukB, failcnt %llu\n",
+ res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10,
+ res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10,
+ res_counter_read_u64(&memcg->kmem, RES_FAILCNT));
}

/*
@@ -3914,6 +3924,11 @@ static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft,
else
val = res_counter_read_u64(&memcg->memsw, name);
break;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ case _KMEM:
+ val = res_counter_read_u64(&memcg->kmem, name);
+ break;
+#endif
default:
BUG();
}
@@ -3951,8 +3966,26 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
break;
if (type == _MEM)
ret = mem_cgroup_resize_limit(memcg, val);
- else
+ else if (type == _MEMSWAP)
ret = mem_cgroup_resize_memsw_limit(memcg, val);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ else if (type == _KMEM) {
+ ret = res_counter_set_limit(&memcg->kmem, val);
+ if (ret)
+ break;
+ /*
+ * Once enabled, can't be disabled. We could in theory
+ * disable it if we haven't yet created any caches, or
+ * if we can shrink them all to death.
+ *
+ * But it is not worth the trouble
+ */
+ if (!memcg->kmem_accounted && val != RESOURCE_MAX)
+ memcg->kmem_accounted = true;
+ }
+#endif
+ else
+ return -EINVAL;
break;
case RES_SOFT_LIMIT:
ret = res_counter_memparse_write_strategy(buffer, &val);
@@ -4017,12 +4050,20 @@ static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
case RES_MAX_USAGE:
if (type == _MEM)
res_counter_reset_max(&memcg->res);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ else if (type == _KMEM)
+ res_counter_reset_max(&memcg->kmem);
+#endif
else
res_counter_reset_max(&memcg->memsw);
break;
case RES_FAILCNT:
if (type == _MEM)
res_counter_reset_failcnt(&memcg->res);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ else if (type == _KMEM)
+ res_counter_reset_failcnt(&memcg->kmem);
+#endif
else
res_counter_reset_failcnt(&memcg->memsw);
break;
@@ -4647,6 +4688,33 @@ static int mem_control_numa_stat_open(struct inode *unused, struct file *file)
#endif /* CONFIG_NUMA */

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+static struct cftype kmem_cgroup_files[] = {
+ {
+ .name = "kmem.limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
+ .write_string = mem_cgroup_write,
+ .read = mem_cgroup_read,
+ },
+ {
+ .name = "kmem.usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
+ .read = mem_cgroup_read,
+ },
+ {
+ .name = "kmem.failcnt",
+ .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
+ .trigger = mem_cgroup_reset,
+ .read = mem_cgroup_read,
+ },
+ {
+ .name = "kmem.max_usage_in_bytes",
+ .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
+ .trigger = mem_cgroup_reset,
+ .read = mem_cgroup_read,
+ },
+ {},
+};
+
static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
{
return mem_cgroup_sockets_init(memcg, ss);
@@ -4654,6 +4722,7 @@ static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)

static void kmem_cgroup_destroy(struct mem_cgroup *memcg)
{
+ BUG_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0);
mem_cgroup_sockets_destroy(memcg);
}
#else
@@ -4979,6 +5048,12 @@ mem_cgroup_create(struct cgroup *cont)
int cpu;
enable_swap_cgroup();
parent = NULL;
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys,
+ kmem_cgroup_files));
+#endif
+
if (mem_cgroup_soft_limit_tree_init())
goto free_out;
root_mem_cgroup = memcg;
@@ -4997,6 +5072,7 @@ mem_cgroup_create(struct cgroup *cont)
if (parent && parent->use_hierarchy) {
res_counter_init(&memcg->res, &parent->res);
res_counter_init(&memcg->memsw, &parent->memsw);
+ res_counter_init(&memcg->kmem, &parent->kmem);
/*
* We increment refcnt of the parent to ensure that we can
* safely access it on res_counter_charge/uncharge.
@@ -5007,6 +5083,7 @@ mem_cgroup_create(struct cgroup *cont)
} else {
res_counter_init(&memcg->res, NULL);
res_counter_init(&memcg->memsw, NULL);
+ res_counter_init(&memcg->kmem, NULL);
}
memcg->last_scanned_node = MAX_NUMNODES;
INIT_LIST_HEAD(&memcg->oom_notify);
@@ -5014,6 +5091,7 @@ mem_cgroup_create(struct cgroup *cont)
if (parent)
memcg->swappiness = mem_cgroup_swappiness(parent);
atomic_set(&memcg->refcnt, 1);
+ memcg->kmem_accounted = false;
memcg->move_charge_at_immigrate = 0;
mutex_init(&memcg->thresholds_lock);
spin_lock_init(&memcg->move_lock);
--
1.7.7.6
[PATCH 08/23] don't force return value checking in res_counter_charge_nofail [message #45996 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
Since we will succeed with the allocation no matter what, there
isn't the need to use __must_check with it. It can very well
be optional.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Michal Hocko <mhocko@suse.cz>
---
include/linux/res_counter.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index da81af0..f7621cf 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -119,7 +119,7 @@ int __must_check res_counter_charge_locked(struct res_counter *counter,
unsigned long val);
int __must_check res_counter_charge(struct res_counter *counter,
unsigned long val, struct res_counter **limit_fail_at);
-int __must_check res_counter_charge_nofail(struct res_counter *counter,
+int res_counter_charge_nofail(struct res_counter *counter,
unsigned long val, struct res_counter **limit_fail_at);

/*
--
1.7.7.6
[PATCH 06/23] slab: use obj_size field of struct kmem_cache when not debugging [message #45997 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
The kmem controller needs to keep track of the object size of
a cache so it can later on create a per-memcg duplicate. Logic
to keep track of that already exists, but it is only enable while
debugging.

This patch makes it also available when the kmem controller code
is compiled in.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
---
include/linux/slab_def.h | 4 +++-
mm/slab.c | 37 ++++++++++++++++++++++++++-----------
2 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index d41effe..cba3139 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -78,8 +78,10 @@ struct kmem_cache {
* variables contain the offset to the user object and its size.
*/
int obj_offset;
- int obj_size;
#endif /* CONFIG_DEBUG_SLAB */
+#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM)
+ int obj_size;
+#endif

/* 6) per-cpu/per-node data, touched during every alloc/free */
/*
diff --git a/mm/slab.c b/mm/slab.c
index c6e5ab8..a0d51dd 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -413,8 +413,28 @@ static void kmem_list3_init(struct kmem_list3 *parent)
#define STATS_INC_FREEMISS(x) do { } while (0)
#endif

-#if DEBUG
+#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM)
+static int obj_size(struct kmem_cache *cachep)
+{
+ return cachep->obj_size;
+}
+static void set_obj_size(struct kmem_cache *cachep, int size)
+{
+ cachep->obj_size = size;
+}
+
+#else
+static int obj_size(struct kmem_cache *cachep)
+{
+ return cachep->buffer_size;
+}
+
+static void set_obj_size(struct kmem_cache *cachep, int size)
+{
+}
+#endif

+#if DEBUG
/*
* memory layout of objects:
* 0 : objp
@@ -433,11 +453,6 @@ static int obj_offset(struct kmem_cache *cachep)
return cachep->obj_offset;
}

-static int obj_size(struct kmem_cache *cachep)
-{
- return cachep->obj_size;
-}
-
static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
{
BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
@@ -465,7 +480,6 @@ static void **dbg_userword(struct kmem_cache *cachep, void *objp)
#else

#define obj_offset(x) 0
-#define obj_size(cachep) (cachep->buffer_size)
#define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
#define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
#define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
@@ -1555,9 +1569,9 @@ void __init kmem_cache_init(void)
*/
cache_cache.buffer_size = offsetof(struct kmem_cache, array[nr_cpu_ids]) +
nr_node_ids * sizeof(struct kmem_list3 *);
-#if DEBUG
- cache_cache.obj_size = cache_cache.buffer_size;
-#endif
+
+ set_obj_size(&cache_cache, cache_cache.buffer_size);
+
cache_cache.buffer_size = ALIGN(cache_cache.buffer_size,
cache_line_size());
cache_cache.reciprocal_buffer_size =
@@ -2418,8 +2432,9 @@ kmem_cache_create (const char *name, size_t size, size_t align,
goto oops;

cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids];
+
+ set_obj_size(cachep, size);
#if DEBUG
- cachep->obj_size = size;

/*
* Both debugging options require word-alignment which is calculated
--
1.7.7.6
[PATCH 01/23] slub: don't create a copy of the name string in kmem_cache_create [message #45998 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
When creating a cache, slub keeps a copy of the cache name through
strdup. The slab however, doesn't do that. This means that everyone
registering caches have to keep a copy themselves anyway, since code
needs to work on all allocators.

Having slab create a copy of it as well may very well be the right
thing to do: but at this point, the callers are already there

My motivation for it comes from the kmem slab cache controller for
memcg. Because we create duplicate caches, having a more consistent
behavior here really helps.

I am sending the patch, however, more to probe on your opinion about
it. If you guys agree, but don't want to merge it - since it is not
fixing anything, nor improving any situation etc, I am more than happy
to carry it in my series until it gets merged (fingers crossed).

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
---
mm/slub.c | 14 ++------------
1 files changed, 2 insertions(+), 12 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index ffe13fd..af8cee9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3925,7 +3925,6 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
size_t align, unsigned long flags, void (*ctor)(void *))
{
struct kmem_cache *s;
- char *n;

if (WARN_ON(!name))
return NULL;
@@ -3949,26 +3948,20 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
return s;
}

- n = kstrdup(name, GFP_KERNEL);
- if (!n)
- goto err;
-
s = kmalloc(kmem_size, GFP_KERNEL);
if (s) {
- if (kmem_cache_open(s, n,
+ if (kmem_cache_open(s, name,
size, align, flags, ctor)) {
list_add(&s->list, &slab_caches);
up_write(&slub_lock);
if (sysfs_slab_add(s)) {
down_write(&slub_lock);
list_del(&s->list);
- kfree(n);
kfree(s);
goto err;
}
return s;
}
- kfree(n);
kfree(s);
}
err:
@@ -5212,7 +5205,6 @@ static void kmem_cache_release(struct kobject *kobj)
{
struct kmem_cache *s = to_slab(kobj);

- kfree(s->name);
kfree(s);
}

@@ -5318,11 +5310,9 @@ static int sysfs_slab_add(struct kmem_cache *s)
return err;
}
kobject_uevent(&s->kobj, KOBJ_ADD);
- if (!unmergeable) {
+ if (!unmergeable)
/* Setup first alias */
sysfs_slab_alias(s, s->name);
- kfree(name);
- }
return 0;
}

--
1.7.7.6
[PATCH 10/23] slab/slub: struct memcg_params [message #45999 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
For the kmem slab controller, we need to record some extra
information in the kmem_cache structure.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
include/linux/slab.h | 15 +++++++++++++++
include/linux/slab_def.h | 4 ++++
include/linux/slub_def.h | 3 +++
3 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index a595dce..a5127e1 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -153,6 +153,21 @@ unsigned int kmem_cache_size(struct kmem_cache *);
#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
#endif

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+struct mem_cgroup_cache_params {
+ struct mem_cgroup *memcg;
+ int id;
+
+#ifdef CONFIG_SLAB
+ /* Original cache parameters, used when creating a memcg cache */
+ size_t orig_align;
+ atomic_t refcnt;
+
+#endif
+ struct list_head destroyed_list; /* Used when deleting cpuset cache */
+};
+#endif
+
/*
* Common kmalloc functions provided by all allocators
*/
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index cba3139..06e4a3e 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -83,6 +83,10 @@ struct kmem_cache {
int obj_size;
#endif

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ struct mem_cgroup_cache_params memcg_params;
+#endif
+
/* 6) per-cpu/per-node data, touched during every alloc/free */
/*
* We put array[] at the end of kmem_cache, because we want to size
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index c2f8c8b..5f5e942 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -102,6 +102,9 @@ struct kmem_cache {
#ifdef CONFIG_SYSFS
struct kobject kobj; /* For sysfs */
#endif
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ struct mem_cgroup_cache_params memcg_params;
+#endif

#ifdef CONFIG_NUMA
/*
--
1.7.7.6
[PATCH 11/23] slub: consider a memcg parameter in kmem_create_cache [message #46000 is a reply to message #45989] Fri, 20 April 2012 21:57 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
Allow a memcg parameter to be passed during cache creation.
The slub allocator will only merge caches that belong to
the same memcg.

Default function is created as a wrapper, passing NULL
to the memcg version. We only merge caches that belong
to the same memcg.

>From the memcontrol.c side, 3 helper functions are created:

1) memcg_css_id: because slub needs a unique cache name
for sysfs. Since this is visible, but not the canonical
location for slab data, the cache name is not used, the
css_id should suffice.

2) mem_cgroup_register_cache: is responsible for assigning
a unique index to each cache, and other general purpose
setup. The index is only assigned for the root caches. All
others are assigned index == -1.

3) mem_cgroup_release_cache: can be called from the root cache
destruction, and will release the index for other caches.

This index mechanism was developed by Suleiman Souhlal.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
include/linux/memcontrol.h | 14 ++++++++++++++
include/linux/slab.h | 6 ++++++
mm/memcontrol.c | 29 +++++++++++++++++++++++++++++
mm/slub.c | 31 +++++++++++++++++++++++++++----
4 files changed, 76 insertions(+), 4 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f94efd2..99e14b9 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -26,6 +26,7 @@ struct mem_cgroup;
struct page_cgroup;
struct page;
struct mm_struct;
+struct kmem_cache;

/* Stats that can be updated by kernel. */
enum mem_cgroup_page_stat_item {
@@ -440,7 +441,20 @@ struct sock;
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
void sock_update_memcg(struct sock *sk);
void sock_release_memcg(struct sock *sk);
+int memcg_css_id(struct mem_cgroup *memcg);
+void mem_cgroup_register_cache(struct mem_cgroup *memcg,
+ struct kmem_cache *s);
+void mem_cgroup_release_cache(struct kmem_cache *cachep);
#else
+static inline void mem_cgroup_register_cache(struct mem_cgroup *memcg,
+ struct kmem_cache *s)
+{
+}
+
+static inline void mem_cgroup_release_cache(struct kmem_cache *cachep)
+{
+}
+
static inline void sock_update_memcg(struct sock *sk)
{
}
diff --git a/include/linux/slab.h b/include/linux/slab.h
index a5127e1..c7a7e05 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -321,6 +321,12 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
__kmalloc(size, flags)
#endif /* DEBUG_SLAB */

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+#define MAX_KMEM_CACHE_TYPES 400
+#else
+#define MAX_KMEM_CACHE_TYPES 0
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
#ifdef CONFIG_NUMA
/*
* kmalloc_node_track_caller is a special version of kmalloc_node that
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 36f1e6b..0015ed0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -323,6 +323,11 @@ struct mem_cgroup {
#endif
};

+int memcg_css_id(struct mem_cgroup *memcg)
+{
+ return css_id(&memcg->css);
+}
+
/* Stuffs for move charges at task migration. */
/*
* Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
@@ -461,6 +466,30 @@ struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
}
EXPORT_SYMBOL(tcp_proto_cgroup);
#endif /* CONFIG_INET */
+
+/* Bitmap used for allocating the cache id numbers. */
+static DECLARE_BITMAP(cache_types, MAX_KMEM_CACHE_TYPES);
+
+void mem_cgroup_register_cache(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep)
+{
+ int id = -1;
+
+ cachep->memcg_params.memcg = memcg;
+
+ if (!memcg) {
+ id = find_first_zero_bit(cache_types, MAX_KMEM_CACHE_TYPES);
+ BUG_ON(id < 0 || id >= MAX_KMEM_CACHE_TYPES);
+ __set_bit(id, cache_types);
+ } else
+ INIT_LIST_HEAD(&cachep->memcg_params.destroyed_list);
+ cachep->memcg_params.id = id;
+}
+
+void mem_cgroup_release_cache(struct kmem_cache *cachep)
+{
+ __clear_bit(cachep->memcg_params.id, cache_types);
+}
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */

static void drain_all_stock_async(struct mem_cgroup *memcg);
diff --git a/mm/slub.c b/mm/slub.c
index 2652e7c..86e40cc 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -32,6 +32,7 @@
#include <linux/prefetch.h>

#include <trace/events/kmem.h>
+#include <linux/memcontrol.h>

/*
* Lock order:
@@ -3880,7 +3881,7 @@ static int slab_unmergeable(struct kmem_cache *s)
return 0;
}

-static struct kmem_cache *find_mergeable(size_t size,
+static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
size_t align, unsigned long flags, const char *name,
void (*ctor)(void *))
{
@@ -3916,21 +3917,29 @@ static struct kmem_cache *find_mergeable(size_t size,
if (s->size - size >= sizeof(void *))
continue;

+ if (memcg && s->memcg_params.memcg != memcg)
+ continue;
+
return s;
}
return NULL;
}

-struct kmem_cache *kmem_cache_create(const char *name, size_t size,
- size_t align, unsigned long flags, void (*ctor)(void *))
+struct kmem_cache *
+kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size,
+ size_t align, unsigned long flags, void (*ctor)(void *))
{
struct kmem_cache *s;

if (WARN_ON(!name))
return NULL;

+#ifndef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ WARN_ON(memcg != NULL);
+#endif
+
down_write(&slub_lock);
- s = find_mergeable(size, align, flags, name, ctor);
+ s = find_mergeable(memcg, size, align, flags, name, ctor);
if (s) {
s->refcount++;
/*
@@ -3954,12 +3963,15 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
size, align, flags, ctor)) {
list_add(&s->list, &slab_caches);
up_write(&slub_lock);
+ mem_cgroup_register_cache(memcg, s);
if (sysfs_slab_add(s)) {
down_write(&slub_lock);
list_del(&s->list);
kfree(s);
goto err;
}
+ if (memcg)
+ s->refcount++;
return s;
}
kfree(s);
@@ -3973,6 +3985,12 @@ err:
s = NULL;
return s;
}
+
+struct kmem_cache *kmem_cache_create(const char *name, size_t size,
+ size_t align, unsigned long flags, void (*ctor)(void *))
+{
+ return kmem_cache_create_memcg(NULL, name, size, align, flags, ctor);
+}
EXPORT_SYMBOL(kmem_cache_create);

#ifdef CONFIG_SMP
@@ -5265,6 +5283,11 @@ static char *create_unique_id(struct kmem_cache *s)
if (p != name + 1)
*p++ = '-';
p += sprintf(p, "%07d", s->size);
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ if (s->memcg_params.memcg)
+ p += sprintf(p, "-%08d", memcg_css_id(s->memcg_params.memcg));
+#endif
BUG_ON(p > name + ID_STR_LENGTH - 1);
return name;
}
--
1.7.7.6
[PATCH 12/23] slab: pass memcg parameter to kmem_cache_create [message #46013 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
Allow a memcg parameter to be passed during cache creation.

Default function is created as a wrapper, passing NULL
to the memcg version. We only merge caches that belong
to the same memcg.

This code was mostly written by Suleiman Souhlal and
only adapted to my patchset, plus a couple of simplifications

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
mm/slab.c | 38 +++++++++++++++++++++++++++++---------
1 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index a0d51dd..362bb6e 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2287,14 +2287,15 @@ static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
* cacheline. This can be beneficial if you're counting cycles as closely
* as davem.
*/
-struct kmem_cache *
-kmem_cache_create (const char *name, size_t size, size_t align,
- unsigned long flags, void (*ctor)(void *))
+static struct kmem_cache *
+__kmem_cache_create(struct mem_cgroup *memcg, const char *name, size_t size,
+ size_t align, unsigned long flags, void (*ctor)(void *))
{
- size_t left_over, slab_size, ralign;
+ size_t left_over, orig_align, ralign, slab_size;
struct kmem_cache *cachep = NULL, *pc;
gfp_t gfp;

+ orig_align = align;
/*
* Sanity checks... these are all serious usage bugs.
*/
@@ -2311,7 +2312,6 @@ kmem_cache_create (const char *name, size_t size, size_t align,
*/
if (slab_is_available()) {
get_online_cpus();
- mutex_lock(&cache_chain_mutex);
}

list_for_each_entry(pc, &cache_chain, next) {
@@ -2331,9 +2331,9 @@ kmem_cache_create (const char *name, size_t size, size_t align,
continue;
}

- if (!strcmp(pc->name, name)) {
+ if (!strcmp(pc->name, name) && !memcg) {
printk(KERN_ERR
- "kmem_cache_create: duplicate cache %s\n", name);
+ "kmem_cache_create: duplicate cache %s\n", name);
dump_stack();
goto oops;
}
@@ -2434,6 +2434,9 @@ kmem_cache_create (const char *name, size_t size, size_t align,
cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids];

set_obj_size(cachep, size);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ cachep->memcg_params.orig_align = orig_align;
+#endif
#if DEBUG

/*
@@ -2541,7 +2544,12 @@ kmem_cache_create (const char *name, size_t size, size_t align,
BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
}
cachep->ctor = ctor;
- cachep->name = name;
+ cachep->name = (char *)name;
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ mem_cgroup_register_cache(memcg, cachep);
+ atomic_set(&cachep->memcg_params.refcnt, 1);
+#endif

if (setup_cpu_cache(cachep, gfp)) {
__kmem_cache_destroy(cachep);
@@ -2566,11 +2574,23 @@ oops:
panic("kmem_cache_create(): failed to create slab `%s'\n",
name);
if (slab_is_available()) {
- mutex_unlock(&cache_chain_mutex);
put_online_cpus();
}
return cachep;
}
+
+struct kmem_cache *
+kmem_cache_create(const char *name, size_t size, size_t align,
+ unsigned long flags, void (*ctor)(void *))
+{
+ struct kmem_cache *cachep;
+
+ mutex_lock(&cache_chain_mutex);
+ cachep = __kmem_cache_create(NULL, name, size, align, flags, ctor);
+ mutex_unlock(&cache_chain_mutex);
+
+ return cachep;
+}
EXPORT_SYMBOL(kmem_cache_create);

#if DEBUG
--
1.7.7.6
[PATCH 21/23] memcg: Track all the memcg children of a kmem_cache. [message #46014 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
From: Suleiman Souhlal <ssouhlal@FreeBSD.org>

This enables us to remove all the children of a kmem_cache being
destroyed, if for example the kernel module it's being used in
gets unloaded. Otherwise, the children will still point to the
destroyed parent.

We also use this to propagate /proc/slabinfo settings to all
the children of a cache, when, for example, changing its
batchsize.

Signed-off-by: Suleiman Souhlal <suleiman@google.com>
---
include/linux/slab.h | 1 +
mm/slab.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 909b508..0dc49fa 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -163,6 +163,7 @@ struct mem_cgroup_cache_params {
size_t orig_align;
atomic_t refcnt;

+ struct list_head sibling_list;
#endif
struct list_head destroyed_list; /* Used when deleting cpuset cache */
};
diff --git a/mm/slab.c b/mm/slab.c
index ac0916b..86f2275 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2561,6 +2561,7 @@ __kmem_cache_create(struct mem_cgroup *memcg, const char *name, size_t size,
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
mem_cgroup_register_cache(memcg, cachep);
atomic_set(&cachep->memcg_params.refcnt, 1);
+ INIT_LIST_HEAD(&cachep->memcg_params.sibling_list);
#endif

if (setup_cpu_cache(cachep, gfp)) {
@@ -2628,6 +2629,8 @@ kmem_cache_dup(struct mem_cgroup *memcg, struct kmem_cache *cachep)
return NULL;
}

+ list_add(&new->memcg_params.sibling_list,
+ &cachep->memcg_params.sibling_list);
if ((cachep->limit != new->limit) ||
(cachep->batchcount != new->batchcount) ||
(cachep->shared != new->shared))
@@ -2815,6 +2818,29 @@ void kmem_cache_destroy(struct kmem_cache *cachep)
{
BUG_ON(!cachep || in_interrupt());

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ /* Destroy all the children caches if we aren't a memcg cache */
+ if (cachep->memcg_params.id != -1) {
+ struct kmem_cache *c;
+ struct mem_cgroup_cache_params *p, *tmp;
+
+ mutex_lock(&cache_chain_mutex);
+ list_for_each_entry_safe(p, tmp,
+ &cachep->memcg_params.sibling_list, sibling_list) {
+ c = container_of(p, struct kmem_cache, memcg_params);
+ if (c == cachep)
+ continue;
+ mutex_unlock(&cache_chain_mutex);
+ BUG_ON(c->memcg_params.id != -1);
+ mem_cgroup_remove_child_kmem_cache(c,
+ cachep->memcg_params.id);
+ kmem_cache_destroy(c);
+ mutex_lock(&cache_chain_mutex);
+ }
+ mutex_unlock(&cache_chain_mutex);
+ }
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
/* Find the cache in the chain of caches. */
get_online_cpus();
mutex_lock(&cache_chain_mutex);
@@ -2822,6 +2848,9 @@ void kmem_cache_destroy(struct kmem_cache *cachep)
* the chain is never empty, cache_cache is never destroyed
*/
list_del(&cachep->next);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ list_del(&cachep->memcg_params.sibling_list);
+#endif
if (__cache_shrink(cachep)) {
slab_error(cachep, "Can't free all objects");
list_add(&cachep->next, &cache_chain);
@@ -4644,11 +4673,27 @@ static ssize_t slabinfo_write(struct file *file, const char __user *buffer,
if (limit < 1 || batchcount < 1 ||
batchcount > limit || shared < 0) {
res = 0;
- } else {
- res = do_tune_cpucache(cachep, limit,
- batchcount, shared,
- GFP_KERNEL);
+ break;
}
+
+ res = do_tune_cpucache(cachep, limit, batchcount,
+ shared, GFP_KERNEL);
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ {
+ struct kmem_cache *c;
+ struct mem_cgroup_cache_params *p;
+
+ list_for_each_entry(p,
+ &cachep->memcg_params.sibling_list,
+ sibling_list) {
+ c = container_of(p, struct kmem_cache,
+ memcg_params);
+ do_tune_cpucache(c, limit, batchcount,
+ shared, GFP_KERNEL);
+ }
+ }
+#endif
break;
}
}
--
1.7.7.6
[PATCH 13/23] slub: create duplicate cache [message #46015 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
This patch provides kmem_cache_dup(), that duplicates
a cache for a memcg, preserving its creation properties.
Object size, alignment and flags are all respected.

When a duplicate cache is created, the parent cache cannot
be destructed during the child lifetime. To assure this,
its reference count is increased if the cache creation
succeeds.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
include/linux/memcontrol.h | 3 +++
include/linux/slab.h | 3 +++
mm/memcontrol.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
mm/slub.c | 37 +++++++++++++++++++++++++++++++++++++
4 files changed, 87 insertions(+), 0 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 99e14b9..493ecdd 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -445,6 +445,9 @@ int memcg_css_id(struct mem_cgroup *memcg);
void mem_cgroup_register_cache(struct mem_cgroup *memcg,
struct kmem_cache *s);
void mem_cgroup_release_cache(struct kmem_cache *cachep);
+extern char *mem_cgroup_cache_name(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep);
+
#else
static inline void mem_cgroup_register_cache(struct mem_cgroup *memcg,
struct kmem_cache *s)
diff --git a/include/linux/slab.h b/include/linux/slab.h
index c7a7e05..909b508 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -323,6 +323,9 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
#define MAX_KMEM_CACHE_TYPES 400
+extern struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep);
+void kmem_cache_drop_ref(struct kmem_cache *cachep);
#else
#define MAX_KMEM_CACHE_TYPES 0
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0015ed0..e881d83 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -467,6 +467,50 @@ struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
EXPORT_SYMBOL(tcp_proto_cgroup);
#endif /* CONFIG_INET */

+/*
+ * This is to prevent races againt the kmalloc cache creations.
+ * Should never be used outside the core memcg code. Therefore,
+ * copy it here, instead of letting it in lib/
+ */
+static char *kasprintf_no_account(gfp_t gfp, const char *fmt, ...)
+{
+ unsigned int len;
+ char *p = NULL;
+ va_list ap, aq;
+
+ va_start(ap, fmt);
+ va_copy(aq, ap);
+ len = vsnprintf(NULL, 0, fmt, aq);
+ va_end(aq);
+
+ p = kmalloc_no_account(len+1, gfp);
+ if (!p)
+ goto out;
+
+ vsnprintf(p, len+1, fmt, ap);
+
+out:
+ va_end(ap);
+ return p;
+}
+
+char *mem_cgroup_cache_name(struct mem_cgroup *memcg, struct kmem_cache *cachep)
+{
+ char *name;
+ struct dentry *dentry = memcg->css.cgroup->dentry;
+
+ BUG_ON(dentry == NULL);
+
+ /* Preallocate the space for "dead" at the end */
+ name = kasprintf_no_account(GFP_KERNEL, "%s(%d:%s)dead",
+ cachep->name, css_id(&memcg->css), dentry->d_name.name);
+
+ if (name)
+ /* Remove "dead" */
+ name[strlen(name) - 4] = '\0';
+ return name;
+}
+
/* Bitmap used for allocating the cache id numbers. */
static DECLARE_BITMAP(cache_types, MAX_KMEM_CACHE_TYPES);

diff --git a/mm/slub.c b/mm/slub.c
index 86e40cc..2285a96 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3993,6 +3993,43 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
}
EXPORT_SYMBOL(kmem_cache_create);

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
+ struct kmem_cache *s)
+{
+ char *name;
+ struct kmem_cache *new;
+
+ name = mem_cgroup_cache_name(memcg, s);
+ if (!name)
+ return NULL;
+
+ new = kmem_cache_create_memcg(memcg, name, s->objsize, s->align,
+ s->allocflags, s->ctor);
+
+ /*
+ * We increase the reference counter in the parent cache, to
+ * prevent it from being deleted. If kmem_cache_destroy() is
+ * called for the root cache before we call it for a child cache,
+ * it will be queued for destruction when we finally drop the
+ * reference on the child cache.
+ */
+ if (new) {
+ down_write(&slub_lock);
+ s->refcount++;
+ up_write(&slub_lock);
+ }
+
+ return new;
+}
+
+void kmem_cache_drop_ref(struct kmem_cache *s)
+{
+ BUG_ON(s->memcg_params.id != -1);
+ kmem_cache_destroy(s);
+}
+#endif
+
#ifdef CONFIG_SMP
/*
* Use the cpu notifier to insure that the cpu slabs are flushed when
--
1.7.7.6
[PATCH 15/23] slab: create duplicate cache [message #46016 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
This patch provides kmem_cache_dup(), that duplicates
a cache for a memcg, preserving its creation properties.
Object size, alignment and flags are all respected.
An exception is the SLAB_PANIC flag, since cache creation
inside a memcg should not be fatal.

This code is mostly written by Suleiman Souhlal,
with some adaptations and simplifications by me.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
mm/slab.c | 36 ++++++++++++++++++++++++++++++++++++
1 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 362bb6e..c4ef684 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -301,6 +301,8 @@ static void free_block(struct kmem_cache *cachep, void **objpp, int len,
int node);
static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
static void cache_reap(struct work_struct *unused);
+static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
+ int batchcount, int shared, gfp_t gfp);

/*
* This function must be completely optimized away if a constant is passed to
@@ -2593,6 +2595,40 @@ kmem_cache_create(const char *name, size_t size, size_t align,
}
EXPORT_SYMBOL(kmem_cache_create);

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+struct kmem_cache *
+kmem_cache_dup(struct mem_cgroup *memcg, struct kmem_cache *cachep)
+{
+ struct kmem_cache *new;
+ int flags;
+ char *name;
+
+ name = mem_cgroup_cache_name(memcg, cachep);
+ if (!name)
+ return NULL;
+
+ flags = cachep->flags & ~SLAB_PANIC;
+ mutex_lock(&cache_chain_mutex);
+ new = __kmem_cache_create(memcg, name, obj_size(cachep),
+ cachep->memcg_params.orig_align, flags, cachep->ctor);
+
+ if (new == NULL) {
+ mutex_unlock(&cache_chain_mutex);
+ kfree(name);
+ return NULL;
+ }
+
+ if ((cachep->limit != new->limit) ||
+ (cachep->batchcount != new->batchcount) ||
+ (cachep->shared != new->shared))
+ do_tune_cpucache(new, cachep->limit, cachep->batchcount,
+ cachep->shared, GFP_KERNEL);
+ mutex_unlock(&cache_chain_mutex);
+
+ return new;
+}
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
#if DEBUG
static void check_irq_off(void)
{
--
1.7.7.6
[PATCH 14/23] slub: provide kmalloc_no_account [message #46017 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
Some allocations need to be accounted to the root memcg regardless
of their context. One trivial example, is the allocations we do
during the memcg slab cache creation themselves. Strictly speaking,
they could go to the parent, but it is way easier to bill them to
the root cgroup.

Only generic kmalloc allocations are allowed to be bypassed.

The function is not exported, because drivers code should always
be accounted.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
include/linux/slub_def.h | 1 +
mm/slub.c | 21 +++++++++++++++++++++
2 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 5f5e942..9a8000a 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -221,6 +221,7 @@ static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
}

void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
+void *kmalloc_no_account(size_t size, gfp_t);
void *__kmalloc(size_t size, gfp_t flags);

static __always_inline void *
diff --git a/mm/slub.c b/mm/slub.c
index 2285a96..d754b06 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3359,6 +3359,27 @@ void *__kmalloc(size_t size, gfp_t flags)
}
EXPORT_SYMBOL(__kmalloc);

+void *kmalloc_no_account(size_t size, gfp_t flags)
+{
+ struct kmem_cache *s;
+ void *ret;
+
+ if (unlikely(size > SLUB_MAX_SIZE))
+ return kmalloc_large(size, flags);
+
+ s = get_slab(size, flags);
+
+ if (unlikely(ZERO_OR_NULL_PTR(s)))
+ return s;
+
+ ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_);
+
+ trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(kmalloc_no_account);
+
#ifdef CONFIG_NUMA
static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
{
--
1.7.7.6
[PATCH 22/23] memcg: Per-memcg memory.kmem.slabinfo file. [message #46018 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
From: Suleiman Souhlal <ssouhlal@FreeBSD.org>

This file shows all the kmem_caches used by a memcg.

Signed-off-by: Suleiman Souhlal <suleiman@google.com>
---
include/linux/slab.h | 1 +
mm/memcontrol.c | 17 ++++++++++
mm/slab.c | 88 +++++++++++++++++++++++++++++++++++++-------------
mm/slub.c | 5 +++
4 files changed, 88 insertions(+), 23 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 0dc49fa..6932205 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -327,6 +327,7 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
extern struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
struct kmem_cache *cachep);
void kmem_cache_drop_ref(struct kmem_cache *cachep);
+int mem_cgroup_slabinfo(struct mem_cgroup *mem, struct seq_file *m);
#else
#define MAX_KMEM_CACHE_TYPES 0
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 547b632..46ebd11 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5092,6 +5092,19 @@ static int mem_control_numa_stat_open(struct inode *unused, struct file *file)
#endif /* CONFIG_NUMA */

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+static int mem_cgroup_slabinfo_show(struct cgroup *cgroup, struct cftype *ctf,
+ struct seq_file *m)
+{
+ struct mem_cgroup *mem;
+
+ mem = mem_cgroup_from_cont(cgroup);
+
+ if (mem == root_mem_cgroup)
+ mem = NULL;
+
+ return mem_cgroup_slabinfo(mem, m);
+}
+
static struct cftype kmem_cgroup_files[] = {
{
.name = "kmem.limit_in_bytes",
@@ -5116,6 +5129,10 @@ static struct cftype kmem_cgroup_files[] = {
.trigger = mem_cgroup_reset,
.read = mem_cgroup_read,
},
+ {
+ .name = "kmem.slabinfo",
+ .read_seq_string = mem_cgroup_slabinfo_show,
+ },
{},
};

diff --git a/mm/slab.c b/mm/slab.c
index 86f2275..3e13fef 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -4518,21 +4519,26 @@ static void s_stop(struct seq_file *m, void *p)
mutex_unlock(&cache_chain_mutex);
}

-static int s_show(struct seq_file *m, void *p)
-{
- struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
- struct slab *slabp;
+struct slab_counts {
unsigned long active_objs;
+ unsigned long active_slabs;
+ unsigned long num_slabs;
+ unsigned long free_objects;
+ unsigned long shared_avail;
unsigned long num_objs;
- unsigned long active_slabs = 0;
- unsigned long num_slabs, free_objects = 0, shared_avail = 0;
- const char *name;
- char *error = NULL;
- int node;
+};
+
+static char *
+get_slab_counts(struct kmem_cache *cachep, struct slab_counts *c)
+{
struct kmem_list3 *l3;
+ struct slab *slabp;
+ char *error;
+ int node;
+
+ error = NULL;
+ memset(c, 0, sizeof(struct slab_counts));

- active_objs = 0;
- num_slabs = 0;
for_each_online_node(node) {
l3 = cachep->nodelists[node];
if (!l3)
@@ -4544,31 +4550,43 @@ static int s_show(struct seq_file *m, void *p)
list_for_each_entry(slabp, &l3->slabs_full, list) {
if (slabp->inuse != cachep->num && !error)
error = "slabs_full accounting error";
- active_objs += cachep->num;
- active_slabs++;
+ c->active_objs += cachep->num;
+ c->active_slabs++;
}
list_for_each_entry(slabp, &l3->slabs_partial, list) {
if (slabp->inuse == cachep->num && !error)
error = "slabs_partial inuse accounting error";
if (!slabp->inuse && !error)
error = "slabs_partial/inuse accounting error";
- active_objs += slabp->inuse;
- active_slabs++;
+ c->active_objs += slabp->inuse;
+ c->active_slabs++;
}
list_for_each_entry(slabp, &l3->slabs_free, list) {
if (slabp->inuse && !error)
error = "slabs_free/inuse accounting error";
- num_slabs++;
+ c->num_slabs++;
}
- free_objects += l3->free_objects;
+ c->free_objects += l3->free_objects;
if (l3->shared)
- shared_avail += l3->shared->avail;
+ c->shared_avail += l3->shared->avail;

spin_unlock_irq(&l3->list_lock);
}
- num_slabs += active_slabs;
- num_objs = num_slabs * cachep->num;
- if (num_objs - active_objs != free_objects && !error)
+ c->num_slabs += c->active_slabs;
+ c->num_objs = c->num_slabs * cachep->num;
+
+ return error;
+}
+
+static int s_show(struct seq_file *m, void *p)
+{
+ struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
+ struct slab_counts c;
+ const char *name;
+ char *error;
+
+ error = get_slab_counts(cachep, &c);
+ if (c.num_objs - c.active_objs != c.free_objects && !error)
error = "free_objects accounting error";

name = cachep->name;
@@ -4576,12 +4594,12 @@ static int s_show(struct seq_file *m, void *p)
printk(KERN_ERR "slab: cache %s error: %s\n", name, error);

seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
- name, active_objs, num_objs, cachep->buffer_size,
+ name, c.active_objs, c.num_objs, cachep->buffer_size,
cachep->num, (1 << cachep->gfporder));
seq_printf(m, " : tunables %4u %4u %4u",
cachep->limit, cachep->batchcount, cachep->shared);
seq_printf(m, " : slabdata %6lu %6lu %6lu",
- active_slabs, num_slabs, shared_avail);
+ c.active_slabs, c.num_slabs, c.shared_avail);
#if STATS
{ /* list3 stats */
unsigned long high = cachep->high_mark;
@@ -4615,6 +4633,30 @@ static int s_show(struct seq_file *m, void *p)
return 0;
}

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+int mem_cgroup_slabinfo(struct mem_cgroup *memcg, struct seq_file *m)
+{
+ struct kmem_cache *cachep;
+ struct slab_counts c;
+
+ seq_printf(m, "# name <active_objs> <num_objs> <objsize>\n");
+
+ mutex_lock(&cache_chain_mutex);
+ list_for_each_entry(cachep, &cache_chain, next) {
+ if (cachep->memcg_params.memcg != memcg)
+ continue;
+
+ get_slab_counts(cachep, &c);
+
+ seq_printf(m, "%-17s %6lu %6lu %6u\n", cachep->name,
+ c.active_objs, c.num_objs, cachep->buffer_size);
+ }
+ mutex_unlock(&cache_chain_mutex);
+
+ return 0;
+}
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
/*
* slabinfo_op - iterator that generates /proc/slabinfo
*
diff --git a/mm/slub.c b/mm/slub.c
index 9b22139..1031d4d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4147,6 +4147,11 @@ void kmem_cache_drop_ref(struct kmem_cache *s)
BUG_ON(s->memcg_params.id != -1);
kmem_cache_destroy(s);
}
+
+int mem_cgroup_slabinfo(struct mem_cgroup *memcg, struct seq_file *m)
+{
+ return 0;
+}
#endif

#ifdef CONFIG_SMP
--
1.7.7.6
[PATCH 16/23] slab: provide kmalloc_no_account [message #46019 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
Some allocations need to be accounted to the root memcg regardless
of their context. One trivial example, is the allocations we do
during the memcg slab cache creation themselves. Strictly speaking,
they could go to the parent, but it is way easier to bill them to
the root cgroup.

Only generic kmalloc allocations are allowed to be bypassed.

The function is not exported, because drivers code should always
be accounted.

This code is mosly written by Suleiman Souhlal.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
include/linux/slab_def.h | 1 +
mm/slab.c | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index 06e4a3e..54d25d7 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -114,6 +114,7 @@ extern struct cache_sizes malloc_sizes[];

void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
void *__kmalloc(size_t size, gfp_t flags);
+void *kmalloc_no_account(size_t size, gfp_t flags);

#ifdef CONFIG_TRACING
extern void *kmem_cache_alloc_trace(size_t size,
diff --git a/mm/slab.c b/mm/slab.c
index c4ef684..13948c3 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3960,6 +3960,29 @@ void *__kmalloc(size_t size, gfp_t flags)
}
EXPORT_SYMBOL(__kmalloc);

+static __always_inline void *__do_kmalloc_no_account(size_t size, gfp_t flags,
+ void *caller)
+{
+ struct kmem_cache *cachep;
+ void *ret;
+
+ cachep = __find_general_cachep(size, flags);
+ if (unlikely(ZERO_OR_NULL_PTR(cachep)))
+ return cachep;
+
+ ret = __cache_alloc(cachep, flags, caller);
+ trace_kmalloc((unsigned long)caller, ret, size,
+ cachep->buffer_size, flags);
+
+ return ret;
+}
+
+void *kmalloc_no_account(size_t size, gfp_t flags)
+{
+ return __do_kmalloc_no_account(size, flags,
+ __builtin_return_address(0));
+}
+
void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
{
return __do_kmalloc(size, flags, (void *)caller);
--
1.7.7.6
[PATCH 18/23] slub: charge allocation to a memcg [message #46020 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
This patch charges allocation of a slab object to a particular
memcg.

The cache is selected with mem_cgroup_get_kmem_cache(),
which is the biggest overhead we pay here, because
it happens at all allocations. However, other than forcing
a function call, this function is not very expensive, and
try to return as soon as we realize we are not a memcg cache.

The charge/uncharge functions are heavier, but are only called
for new page allocations.

The kmalloc_no_account variant is patched so the base
function is used and we don't even try to do cache
selection.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
include/linux/slub_def.h | 32 ++++++++++--
mm/slub.c | 124 +++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 138 insertions(+), 18 deletions(-)

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 9a8000a..e75efcb 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -13,6 +13,7 @@
#include <linux/kobject.h>

#include <linux/kmemleak.h>
+#include <linux/memcontrol.h>

enum stat_item {
ALLOC_FASTPATH, /* Allocation from cpu slab */
@@ -210,14 +211,21 @@ static __always_inline int kmalloc_index(size_t size)
* This ought to end up with a global pointer to the right cache
* in kmalloc_caches.
*/
-static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
+static __always_inline struct kmem_cache *kmalloc_slab(gfp_t flags, size_t size)
{
+ struct kmem_cache *s;
int index = kmalloc_index(size);

if (index == 0)
return NULL;

- return kmalloc_caches[index];
+ s = kmalloc_caches[index];
+
+ rcu_read_lock();
+ s = mem_cgroup_get_kmem_cache(s, flags);
+ rcu_read_unlock();
+
+ return s;
}

void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
@@ -225,13 +233,27 @@ void *kmalloc_no_account(size_t size, gfp_t);
void *__kmalloc(size_t size, gfp_t flags);

static __always_inline void *
-kmalloc_order(size_t size, gfp_t flags, unsigned int order)
+kmalloc_order_base(size_t size, gfp_t flags, unsigned int order)
{
void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
kmemleak_alloc(ret, size, 1, flags);
return ret;
}

+static __always_inline void *
+kmalloc_order(size_t size, gfp_t flags, unsigned int order)
+{
+ void *ret = NULL;
+
+ if (!mem_cgroup_charge_kmem(flags, size))
+ return NULL;
+
+ ret = kmalloc_order_base(size, flags, order);
+ if (!ret)
+ mem_cgroup_uncharge_kmem((1 << order) << PAGE_SHIFT);
+ return ret;
+}
+
/**
* Calling this on allocated memory will check that the memory
* is expected to be in use, and print warnings if not.
@@ -276,7 +298,7 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
return kmalloc_large(size, flags);

if (!(flags & SLUB_DMA)) {
- struct kmem_cache *s = kmalloc_slab(size);
+ struct kmem_cache *s = kmalloc_slab(flags, size);

if (!s)
return ZERO_SIZE_PTR;
@@ -309,7 +331,7 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
{
if (__builtin_constant_p(size) &&
size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
- struct kmem_cache *s = kmalloc_slab(size);
+ struct kmem_cache *s = kmalloc_slab(flags, size);

if (!s)
return ZERO_SIZE_PTR;
diff --git a/mm/slub.c b/mm/slub.c
index d754b06..9b22139 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1283,11 +1283,17 @@ static inline struct page *alloc_slab_page(gfp_t flags, int node,
return alloc_pages_exact_node(node, flags, order);
}

+static inline unsigned long size_in_bytes(unsigned int order)
+{
+ return (1 << order) << PAGE_SHIFT;
+}
+
static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
{
- struct page *page;
+ struct page *page = NULL;
struct kmem_cache_order_objects oo = s->oo;
gfp_t alloc_gfp;
+ unsigned int memcg_allowed = oo_order(oo);

flags &= gfp_allowed_mask;

@@ -1296,13 +1302,29 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)

flags |= s->allocflags;

- /*
- * Let the initial higher-order allocation fail under memory pressure
- * so we fall-back to the minimum order allocation.
- */
- alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
+ memcg_allowed = oo_order(oo);
+ if (!mem_cgroup_charge_slab(s, flags, size_in_bytes(memcg_allowed))) {
+
+ memcg_allowed = oo_order(s->min);
+ if (!mem_cgroup_charge_slab(s, flags,
+ size_in_bytes(memcg_allowed))) {
+ if (flags & __GFP_WAIT)
+ local_irq_disable();
+ return NULL;
+ }
+ }
+
+ if (memcg_allowed == oo_order(oo)) {
+ /*
+ * Let the initial higher-order allocation fail under memory
+ * pressure so we fall-back to the minimum order allocation.
+ */
+ alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) &
+ ~__GFP_NOFAIL;
+
+ page = alloc_slab_page(alloc_gfp, node, oo);
+ }

- page = alloc_slab_page(alloc_gfp, node, oo);
if (unlikely(!page)) {
oo = s->min;
/*
@@ -1313,13 +1335,23 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)

if (page)
stat(s, ORDER_FALLBACK);
+ /*
+ * We reserved more than we used, time to give it back
+ */
+ if (page && memcg_allowed != oo_order(oo)) {
+ unsigned long delta;
+ delta = memcg_allowed - oo_order(oo);
+ mem_cgroup_uncharge_slab(s, size_in_bytes(delta));
+ }
}

if (flags & __GFP_WAIT)
local_irq_disable();

- if (!page)
+ if (!page) {
+ mem_cgroup_uncharge_slab(s, size_in_bytes(memcg_allowed));
return NULL;
+ }

if (kmemcheck_enabled
&& !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
@@ -1393,6 +1425,24 @@ out:
return page;
}

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+static unsigned long slab_nr_pages(struct kmem_cache *s)
+{
+ int node;
+ unsigned long nr_slabs = 0;
+
+ for_each_online_node(node) {
+ struct kmem_cache_node *n = get_node(s, node);
+
+ if (!n)
+ continue;
+ nr_slabs += atomic_long_read(&n->nr_slabs);
+ }
+
+ return nr_slabs << oo_order(s->oo);
+}
+#endif
+
static void __free_slab(struct kmem_cache *s, struct page *page)
{
int order = compound_order(page);
@@ -1419,6 +1469,12 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
if (current->reclaim_state)
current->reclaim_state->reclaimed_slab += pages;
__free_pages(page, order);
+
+ mem_cgroup_uncharge_slab(s, (1 << order) << PAGE_SHIFT);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ if (s->memcg_params.memcg && (slab_nr_pages(s) == 0))
+ mem_cgroup_destroy_cache(s);
+#endif
}

#define need_reserve_slab_rcu \
@@ -2300,8 +2356,9 @@ new_slab:
*
* Otherwise we can simply pick the next object from the lockless free list.
*/
-static __always_inline void *slab_alloc(struct kmem_cache *s,
- gfp_t gfpflags, int node, unsigned long addr)
+static __always_inline void *slab_alloc_base(struct kmem_cache *s,
+ gfp_t gfpflags, int node,
+ unsigned long addr)
{
void **object;
struct kmem_cache_cpu *c;
@@ -2369,6 +2426,24 @@ redo:
return object;
}

+static __always_inline void *slab_alloc(struct kmem_cache *s,
+ gfp_t gfpflags, int node, unsigned long addr)
+{
+
+ if (slab_pre_alloc_hook(s, gfpflags))
+ return NULL;
+
+ if (in_interrupt() || (current == NULL) || (gfpflags & __GFP_NOFAIL))
+ goto kernel_alloc;
+
+ rcu_read_lock();
+ s = mem_cgroup_get_kmem_cache(s, gfpflags);
+ rcu_read_unlock();
+
+kernel_alloc:
+ return slab_alloc_base(s, gfpflags, node, addr);
+}
+
void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
{
void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
@@ -3194,6 +3269,13 @@ void kmem_cache_destroy(struct kmem_cache *s)
s->refcount--;
if (!s->refcount) {
list_del(&s->list);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ /* Not a memcg cache */
+ if (s->memcg_params.id != -1) {
+ mem_cgroup_release_cache(s);
+ mem_cgroup_flush_cache_create_queue();
+ }
+#endif
up_write(&slub_lock);
if (kmem_cache_close(s)) {
printk(KERN_ERR "SLUB %s: %s called for cache that "
@@ -3273,6 +3355,7 @@ static struct kmem_cache *__init create_kmalloc_cache(const char *name,
goto panic;

list_add(&s->list, &slab_caches);
+ mem_cgroup_register_cache(NULL, s);
return s;

panic:
@@ -3364,15 +3447,21 @@ void *kmalloc_no_account(size_t size, gfp_t flags)
struct kmem_cache *s;
void *ret;

- if (unlikely(size > SLUB_MAX_SIZE))
- return kmalloc_large(size, flags);
+ if (unlikely(size > SLUB_MAX_SIZE)) {
+ unsigned int order = get_order(size);
+ ret = kmalloc_order_base(size, flags, order);
+#ifdef CONFIG_TRACING
+ trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
+#endif
+ return ret;
+ }

s = get_slab(size, flags);

if (unlikely(ZERO_OR_NULL_PTR(s)))
return s;

- ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_);
+ ret = slab_alloc_base(s, flags, NUMA_NO_NODE, _RET_IP_);

trace_kmalloc(_RET_IP_, ret, size, s->size, flags);

@@ -3387,10 +3476,17 @@ static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
void *ptr = NULL;

flags |= __GFP_COMP | __GFP_NOTRACK;
+
+ if (!mem_cgroup_charge_kmem(flags, size))
+ goto out;
+
page = alloc_pages_node(node, flags, get_order(size));
if (page)
ptr = page_address(page);
+ else
+ mem_cgroup_uncharge_kmem(size);

+out:
kmemleak_alloc(ptr, size, 1, flags);
return ptr;
}
@@ -3938,8 +4034,10 @@ static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
if (s->size - size >= sizeof(voi
...

[PATCH 17/23] kmem controller charge/uncharge infrastructure [message #46021 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
With all the dependencies already in place, this patch introduces
the charge/uncharge functions for the slab cache accounting in memcg.

Before we can charge a cache, we need to select the right cache.
This is done by using the function __mem_cgroup_get_kmem_cache().

If we should use the root kmem cache, this function tries to detect
that and return as early as possible.

The charge and uncharge functions comes in two flavours:
* __mem_cgroup_(un)charge_slab(), that assumes the allocation is
a slab page, and
* __mem_cgroup_(un)charge_kmem(), that does not. This later exists
because the slub allocator draws the larger kmalloc allocations
from the page allocator.

In memcontrol.h those functions are wrapped in inline acessors.
The idea is to later on, patch those with jump labels, so we don't
incur any overhead when no mem cgroups are being used.

Because the slub allocator tends to inline the allocations whenever
it can, those functions need to be exported so modules can make use
of it properly.

I apologize in advance to the reviewers. This patch is quite big, but
I was not able to split it any further due to all the dependencies
between the code.

This code is inspired by the code written by Suleiman Souhlal,
but heavily changed.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
include/linux/memcontrol.h | 68 ++++++++
init/Kconfig | 2 +-
mm/memcontrol.c | 373 +++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 441 insertions(+), 2 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 493ecdd..c1c1302 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -448,6 +448,21 @@ void mem_cgroup_release_cache(struct kmem_cache *cachep);
extern char *mem_cgroup_cache_name(struct mem_cgroup *memcg,
struct kmem_cache *cachep);

+void mem_cgroup_flush_cache_create_queue(void);
+void mem_cgroup_remove_child_kmem_cache(struct kmem_cache *cachep, int id);
+bool __mem_cgroup_charge_slab(struct kmem_cache *cachep, gfp_t gfp,
+ size_t size);
+void __mem_cgroup_uncharge_slab(struct kmem_cache *cachep, size_t size);
+
+bool __mem_cgroup_charge_kmem(gfp_t gfp, size_t size);
+void __mem_cgroup_uncharge_kmem(size_t size);
+
+struct kmem_cache *
+__mem_cgroup_get_kmem_cache(struct kmem_cache *cachep, gfp_t gfp);
+
+#define mem_cgroup_kmem_on 1
+
+void mem_cgroup_destroy_cache(struct kmem_cache *cachep);
#else
static inline void mem_cgroup_register_cache(struct mem_cgroup *memcg,
struct kmem_cache *s)
@@ -464,6 +479,59 @@ static inline void sock_update_memcg(struct sock *sk)
static inline void sock_release_memcg(struct sock *sk)
{
}
+
+static inline void
+mem_cgroup_flush_cache_create_queue(void)
+{
+}
+
+static inline void mem_cgroup_destroy_cache(struct kmem_cache *cachep)
+{
+}
+
+#define mem_cgroup_kmem_on 0
+#define __mem_cgroup_get_kmem_cache(a, b) a
+#define __mem_cgroup_charge_slab(a, b, c) false
+#define __mem_cgroup_charge_kmem(a, b) false
+#define __mem_cgroup_uncharge_slab(a, b)
+#define __mem_cgroup_uncharge_kmem(b)
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+static __always_inline struct kmem_cache *
+mem_cgroup_get_kmem_cache(struct kmem_cache *cachep, gfp_t gfp)
+{
+ if (mem_cgroup_kmem_on)
+ return __mem_cgroup_get_kmem_cache(cachep, gfp);
+ return cachep;
+}
+
+static __always_inline bool
+mem_cgroup_charge_slab(struct kmem_cache *cachep, gfp_t gfp, size_t size)
+{
+ if (mem_cgroup_kmem_on)
+ return __mem_cgroup_charge_slab(cachep, gfp, size);
+ return true;
+}
+
+static __always_inline void
+mem_cgroup_uncharge_slab(struct kmem_cache *cachep, size_t size)
+{
+ if (mem_cgroup_kmem_on)
+ __mem_cgroup_uncharge_slab(cachep, size);
+}
+
+static __always_inline
+bool mem_cgroup_charge_kmem(gfp_t gfp, size_t size)
+{
+ if (mem_cgroup_kmem_on)
+ return __mem_cgroup_charge_kmem(gfp, size);
+ return true;
+}
+
+static __always_inline
+void mem_cgroup_uncharge_kmem(size_t size)
+{
+ if (mem_cgroup_kmem_on)
+ __mem_cgroup_uncharge_kmem(size);
+}
#endif /* _LINUX_MEMCONTROL_H */

diff --git a/init/Kconfig b/init/Kconfig
index 72f33fa..071b7e3 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -696,7 +696,7 @@ config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
then swapaccount=0 does the trick).
config CGROUP_MEM_RES_CTLR_KMEM
bool "Memory Resource Controller Kernel Memory accounting (EXPERIMENTAL)"
- depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL
+ depends on CGROUP_MEM_RES_CTLR && EXPERIMENTAL && !SLOB
default n
help
The Kernel Memory extension for Memory Resource Controller can limit
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e881d83..ae61e99 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -10,6 +10,10 @@
* Copyright (C) 2009 Nokia Corporation
* Author: Kirill A. Shutemov
*
+ * Kernel Memory Controller
+ * Copyright (C) 2012 Parallels Inc. and Google Inc.
+ * Authors: Glauber Costa and Suleiman Souhlal
+ *
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
@@ -321,6 +325,11 @@ struct mem_cgroup {
#ifdef CONFIG_INET
struct tcp_memcontrol tcp_mem;
#endif
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ /* Slab accounting */
+ struct kmem_cache *slabs[MAX_KMEM_CACHE_TYPES];
+#endif
};

int memcg_css_id(struct mem_cgroup *memcg)
@@ -414,6 +423,9 @@ static void mem_cgroup_put(struct mem_cgroup *memcg);
#include <net/ip.h>

static bool mem_cgroup_is_root(struct mem_cgroup *memcg);
+static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, s64 delta);
+static void memcg_uncharge_kmem(struct mem_cgroup *memcg, s64 delta);
+
void sock_update_memcg(struct sock *sk)
{
if (mem_cgroup_sockets_enabled) {
@@ -513,6 +525,13 @@ char *mem_cgroup_cache_name(struct mem_cgroup *memcg, struct kmem_cache *cachep)

/* Bitmap used for allocating the cache id numbers. */
static DECLARE_BITMAP(cache_types, MAX_KMEM_CACHE_TYPES);
+static DEFINE_MUTEX(memcg_cache_mutex);
+
+static inline bool mem_cgroup_kmem_enabled(struct mem_cgroup *memcg)
+{
+ return !mem_cgroup_disabled() && memcg &&
+ !mem_cgroup_is_root(memcg) && memcg->kmem_accounted;
+}

void mem_cgroup_register_cache(struct mem_cgroup *memcg,
struct kmem_cache *cachep)
@@ -534,6 +553,300 @@ void mem_cgroup_release_cache(struct kmem_cache *cachep)
{
__clear_bit(cachep->memcg_params.id, cache_types);
}
+
+static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep)
+{
+ struct kmem_cache *new_cachep;
+ int idx;
+
+ BUG_ON(!mem_cgroup_kmem_enabled(memcg));
+
+ idx = cachep->memcg_params.id;
+
+ mutex_lock(&memcg_cache_mutex);
+ new_cachep = memcg->slabs[idx];
+ if (new_cachep)
+ goto out;
+
+ new_cachep = kmem_cache_dup(memcg, cachep);
+
+ if (new_cachep == NULL) {
+ new_cachep = cachep;
+ goto out;
+ }
+
+ mem_cgroup_get(memcg);
+ memcg->slabs[idx] = new_cachep;
+ new_cachep->memcg_params.memcg = memcg;
+out:
+ mutex_unlock(&memcg_cache_mutex);
+ return new_cachep;
+}
+
+struct create_work {
+ struct mem_cgroup *memcg;
+ struct kmem_cache *cachep;
+ struct list_head list;
+};
+
+/* Use a single spinlock for destruction and creation, not a frequent op */
+static DEFINE_SPINLOCK(cache_queue_lock);
+static LIST_HEAD(create_queue);
+static LIST_HEAD(destroyed_caches);
+
+static void kmem_cache_destroy_work_func(struct work_struct *w)
+{
+ struct kmem_cache *cachep;
+ char *name;
+
+ spin_lock_irq(&cache_queue_lock);
+ while (!list_empty(&destroyed_caches)) {
+ cachep = container_of(list_first_entry(&destroyed_caches,
+ struct mem_cgroup_cache_params, destroyed_list), struct
+ kmem_cache, memcg_params);
+ name = (char *)cachep->name;
+ list_del(&cachep->memcg_params.destroyed_list);
+ spin_unlock_irq(&cache_queue_lock);
+ synchronize_rcu();
+ kmem_cache_destroy(cachep);
+ kfree(name);
+ spin_lock_irq(&cache_queue_lock);
+ }
+ spin_unlock_irq(&cache_queue_lock);
+}
+static DECLARE_WORK(kmem_cache_destroy_work, kmem_cache_destroy_work_func);
+
+void mem_cgroup_destroy_cache(struct kmem_cache *cachep)
+{
+ unsigned long flags;
+
+ BUG_ON(cachep->memcg_params.id != -1);
+
+ /*
+ * We have to defer the actual destroying to a workqueue, because
+ * we might currently be in a context that cannot sleep.
+ */
+ spin_lock_irqsave(&cache_queue_lock, flags);
+ list_add(&cachep->memcg_params.destroyed_list, &destroyed_caches);
+ spin_unlock_irqrestore(&cache_queue_lock, flags);
+
+ schedule_work(&kmem_cache_destroy_work);
+}
+
+
+/*
+ * Flush the queue of kmem_caches to create, because we're creating a cgroup.
+ *
+ * We might end up flushing other cgroups' creation requests as well, but
+ * they will just get queued again next time someone tries to make a slab
+ * allocation for them.
+ */
+void mem_cgroup_flush_cache_create_queue(void)
+{
+ struct create_work *cw, *tmp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cache_queue_lock, flags);
+ list_for_each_entry_safe(cw, tmp, &create_queue, list) {
+ list_del(&cw->list);
+ kfree(cw);
+ }
+ spin_unlock_irqrestore(&cache_queue_lock, flags);
+}
+
+static void memcg_create_cache_work_func(struct work_struct *w)
+{
+ struct kmem_cache *cachep;
+ struct create_work *cw;
+
+ spin_lock_irq(&cache_queue_lock);
+ while (!list_empty(&create_queue)) {
+ cw = list_first_entry(&create_queue, struct create_work, list
...

[PATCH 19/23] slab: per-memcg accounting of slab caches [message #46022 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
This patch charges allocation of a slab object to a particular
memcg.

The cache is selected with mem_cgroup_get_kmem_cache(),
which is the biggest overhead we pay here, because
it happens at all allocations. However, other than forcing
a function call, this function is not very expensive, and
try to return as soon as we realize we are not a memcg cache.

The charge/uncharge functions are heavier, but are only called
for new page allocations.

Code is heavily inspired by Suleiman's, with adaptations to
the patchset and minor simplifications by me.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
include/linux/slab_def.h | 66 ++++++++++++++++++++++++++++-
mm/slab.c | 105 ++++++++++++++++++++++++++++++++++++++++++----
2 files changed, 162 insertions(+), 9 deletions(-)

diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index 54d25d7..c4f7e45 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -51,7 +51,7 @@ struct kmem_cache {
void (*ctor)(void *obj);

/* 4) cache creation/removal */
- const char *name;
+ char *name;
struct list_head next;

/* 5) statistics */
@@ -219,4 +219,68 @@ found:

#endif /* CONFIG_NUMA */

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+
+void kmem_cache_drop_ref(struct kmem_cache *cachep);
+
+static inline void
+kmem_cache_get_ref(struct kmem_cache *cachep)
+{
+ if (cachep->memcg_params.id == -1 &&
+ unlikely(!atomic_add_unless(&cachep->memcg_params.refcnt, 1, 0)))
+ BUG();
+}
+
+static inline void
+mem_cgroup_put_kmem_cache(struct kmem_cache *cachep)
+{
+ rcu_read_unlock();
+}
+
+static inline void
+mem_cgroup_kmem_cache_prepare_sleep(struct kmem_cache *cachep)
+{
+ /*
+ * Make sure the cache doesn't get freed while we have interrupts
+ * enabled.
+ */
+ kmem_cache_get_ref(cachep);
+ rcu_read_unlock();
+}
+
+static inline void
+mem_cgroup_kmem_cache_finish_sleep(struct kmem_cache *cachep)
+{
+ rcu_read_lock();
+ kmem_cache_drop_ref(cachep);
+}
+
+#else /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
+static inline void
+kmem_cache_get_ref(struct kmem_cache *cachep)
+{
+}
+
+static inline void
+kmem_cache_drop_ref(struct kmem_cache *cachep)
+{
+}
+
+static inline void
+mem_cgroup_put_kmem_cache(struct kmem_cache *cachep)
+{
+}
+
+static inline void
+mem_cgroup_kmem_cache_prepare_sleep(struct kmem_cache *cachep)
+{
+}
+
+static inline void
+mem_cgroup_kmem_cache_finish_sleep(struct kmem_cache *cachep)
+{
+}
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
#endif /* _LINUX_SLAB_DEF_H */
diff --git a/mm/slab.c b/mm/slab.c
index 13948c3..ac0916b 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1818,20 +1818,28 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
flags |= __GFP_RECLAIMABLE;

+ nr_pages = (1 << cachep->gfporder);
+ if (!mem_cgroup_charge_slab(cachep, flags, nr_pages * PAGE_SIZE))
+ return NULL;
+
page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
if (!page) {
if (!(flags & __GFP_NOWARN) && printk_ratelimit())
slab_out_of_memory(cachep, flags, nodeid);
+
+ mem_cgroup_uncharge_slab(cachep, nr_pages * PAGE_SIZE);
return NULL;
}

- nr_pages = (1 << cachep->gfporder);
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
add_zone_page_state(page_zone(page),
NR_SLAB_RECLAIMABLE, nr_pages);
else
add_zone_page_state(page_zone(page),
NR_SLAB_UNRECLAIMABLE, nr_pages);
+
+ kmem_cache_get_ref(cachep);
+
for (i = 0; i < nr_pages; i++)
__SetPageSlab(page + i);

@@ -1864,6 +1872,8 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr)
else
sub_zone_page_state(page_zone(page),
NR_SLAB_UNRECLAIMABLE, nr_freed);
+ mem_cgroup_uncharge_slab(cachep, i * PAGE_SIZE);
+ kmem_cache_drop_ref(cachep);
while (i--) {
BUG_ON(!PageSlab(page));
__ClearPageSlab(page);
@@ -2823,12 +2833,28 @@ void kmem_cache_destroy(struct kmem_cache *cachep)
if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
rcu_barrier();

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ /* Not a memcg cache */
+ if (cachep->memcg_params.id != -1) {
+ mem_cgroup_release_cache(cachep);
+ mem_cgroup_flush_cache_create_queue();
+ }
+#endif
__kmem_cache_destroy(cachep);
mutex_unlock(&cache_chain_mutex);
put_online_cpus();
}
EXPORT_SYMBOL(kmem_cache_destroy);

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+void kmem_cache_drop_ref(struct kmem_cache *cachep)
+{
+ if (cachep->memcg_params.id == -1 &&
+ unlikely(atomic_dec_and_test(&cachep->memcg_params.refcnt)))
+ mem_cgroup_destroy_cache(cachep);
+}
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
/*
* Get the memory for a slab management obj.
* For a slab cache when the slab descriptor is off-slab, slab descriptors
@@ -3028,8 +3054,10 @@ static int cache_grow(struct kmem_cache *cachep,

offset *= cachep->colour_off;

- if (local_flags & __GFP_WAIT)
+ if (local_flags & __GFP_WAIT) {
local_irq_enable();
+ mem_cgroup_kmem_cache_prepare_sleep(cachep);
+ }

/*
* The test for missing atomic flag is performed here, rather than
@@ -3058,8 +3086,10 @@ static int cache_grow(struct kmem_cache *cachep,

cache_init_objs(cachep, slabp);

- if (local_flags & __GFP_WAIT)
+ if (local_flags & __GFP_WAIT) {
local_irq_disable();
+ mem_cgroup_kmem_cache_finish_sleep(cachep);
+ }
check_irq_off();
spin_lock(&l3->list_lock);

@@ -3072,8 +3102,10 @@ static int cache_grow(struct kmem_cache *cachep,
opps1:
kmem_freepages(cachep, objp);
failed:
- if (local_flags & __GFP_WAIT)
+ if (local_flags & __GFP_WAIT) {
local_irq_disable();
+ mem_cgroup_kmem_cache_finish_sleep(cachep);
+ }
return 0;
}

@@ -3834,11 +3866,15 @@ static inline void __cache_free(struct kmem_cache *cachep, void *objp,
*/
void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
{
- void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
+ void *ret;
+
+ rcu_read_lock();
+ cachep = mem_cgroup_get_kmem_cache(cachep, flags);
+ rcu_read_unlock();
+ ret = __cache_alloc(cachep, flags, __builtin_return_address(0));

trace_kmem_cache_alloc(_RET_IP_, ret,
obj_size(cachep), cachep->buffer_size, flags);
-
return ret;
}
EXPORT_SYMBOL(kmem_cache_alloc);
@@ -3849,6 +3885,10 @@ kmem_cache_alloc_trace(size_t size, struct kmem_cache *cachep, gfp_t flags)
{
void *ret;

+ rcu_read_lock();
+ cachep = mem_cgroup_get_kmem_cache(cachep, flags);
+ rcu_read_unlock();
+
ret = __cache_alloc(cachep, flags, __builtin_return_address(0));

trace_kmalloc(_RET_IP_, ret,
@@ -3861,13 +3901,17 @@ EXPORT_SYMBOL(kmem_cache_alloc_trace);
#ifdef CONFIG_NUMA
void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
{
- void *ret = __cache_alloc_node(cachep, flags, nodeid,
+ void *ret;
+
+ rcu_read_lock();
+ cachep = mem_cgroup_get_kmem_cache(cachep, flags);
+ rcu_read_unlock();
+ ret = __cache_alloc_node(cachep, flags, nodeid,
__builtin_return_address(0));

trace_kmem_cache_alloc_node(_RET_IP_, ret,
obj_size(cachep), cachep->buffer_size,
flags, nodeid);
-
return ret;
}
EXPORT_SYMBOL(kmem_cache_alloc_node);
@@ -3880,6 +3924,9 @@ void *kmem_cache_alloc_node_trace(size_t size,
{
void *ret;

+ rcu_read_lock();
+ cachep = mem_cgroup_get_kmem_cache(cachep, flags);
+ rcu_read_unlock();
ret = __cache_alloc_node(cachep, flags, nodeid,
__builtin_return_address(0));
trace_kmalloc_node(_RET_IP_, ret,
@@ -4011,9 +4058,33 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)

local_irq_save(flags);
debug_check_no_locks_freed(objp, obj_size(cachep));
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ {
+ struct kmem_cache *actual_cachep;
+
+ actual_cachep = virt_to_cache(objp);
+ if (actual_cachep != cachep) {
+ VM_BUG_ON(actual_cachep->memcg_params.id != -1);
+ cachep = actual_cachep;
+ }
+ /*
+ * Grab a reference so that the cache is guaranteed to stay
+ * around.
+ * If we are freeing the last object of a dead memcg cache,
+ * the kmem_cache_drop_ref() at the end of this function
+ * will end up freeing the cache.
+ */
+ kmem_cache_get_ref(cachep);
+ }
+#endif
+
if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
debug_check_no_obj_freed(objp, obj_size(cachep));
__cache_free(cachep, objp, __builtin_return_address(0));
+
+ kmem_cache_drop_ref(cachep);
+
local_irq_restore(flags);

trace_kmem_cache_free(_RET_IP_, objp);
@@ -4041,9 +4112,19 @@ void kfree(const void *objp)
local_irq_save(flags);
kfree_debugcheck(objp);
c = virt_to_cache(objp);
+
+ /*
+ * Grab a reference so that the cache is guaranteed to stay around.
+ * If we are freeing the last object of a dead memcg cache, the
+ * kmem_cache_drop_ref() at the end of this function will end up
+ * freeing the cache.
+ */
+ kmem_cache_get_ref(c);
+
debug_check_no_locks_freed(objp, obj_size(c));
debug_check_no_obj_freed(objp, obj_size(c));
__cache_free(c, (void *)objp, __builtin_return_address(0));
+ kmem_cache_drop_ref(c);
local_irq_restore(flags);
}
EXPORT_SYMBOL(kfree);
@@ -4312,6 +4393,13 @@ static void cache_reap(struct work_struct *w)
list_for_each_entry(searchp, &cache_chain, next) {
check_irq_on();

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ /* For memcg caches, make sure we only reap the active ones. */
+ if (searchp->memcg_params.id == -1 &&
+ !atomic_add_unless(&searchp->memcg_params.refcnt, 1, 0))
+ continue;
+#endif
+
/*
* We only take the l3 lock if absolutely necessary and we
* hav
...

[PATCH 23/23] slub: create slabinfo file for memcg [message #46023 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
This patch implements mem_cgroup_slabinfo() for the slub.
With that, we can also probe the used caches for it.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
mm/slub.c | 27 +++++++++++++++++++++++++++
1 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 1031d4d..495a4f1 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4150,6 +4150,33 @@ void kmem_cache_drop_ref(struct kmem_cache *s)

int mem_cgroup_slabinfo(struct mem_cgroup *memcg, struct seq_file *m)
{
+ struct kmem_cache *s;
+ int node;
+ unsigned long nr_objs = 0;
+ unsigned long nr_free = 0;
+
+ seq_printf(m, "# name <active_objs> <num_objs> <objsize>\n");
+
+ down_read(&slub_lock);
+ list_for_each_entry(s, &slab_caches, list) {
+ if (s->memcg_params.memcg != memcg)
+ continue;
+
+ for_each_online_node(node) {
+ struct kmem_cache_node *n = get_node(s, node);
+
+ if (!n)
+ continue;
+
+ nr_objs += atomic_long_read(&n->total_objects);
+ nr_free += count_partial(n, count_free);
+ }
+
+ seq_printf(m, "%-17s %6lu %6lu %6u\n", s->name,
+ nr_objs - nr_free, nr_objs, s->size);
+ }
+ up_read(&slub_lock);
+
return 0;
}
#endif
--
1.7.7.6
[PATCH 20/23] memcg: disable kmem code when not in use. [message #46024 is a reply to message #45989] Sun, 22 April 2012 23:53 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *parallels.com
We can use jump labels to patch the code in or out
when not used.

Because the assignment: memcg->kmem_accounted = true
is done after the jump labels increment, we guarantee
that the root memcg will always be selected until
all call sites are patched (see mem_cgroup_kmem_enabled).
This guarantees that no mischarges are applied.

Jump label decrement happens when the last reference
count from the memcg dies. This will only happen when
the caches are all dead.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Suleiman Souhlal <suleiman@google.com>
---
include/linux/memcontrol.h | 4 +++-
mm/memcontrol.c | 21 ++++++++++++++++++++-
2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index c1c1302..25c4324 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -21,6 +21,7 @@
#define _LINUX_MEMCONTROL_H
#include <linux/cgroup.h>
#include <linux/vm_event_item.h>
+#include <linux/jump_label.h>

struct mem_cgroup;
struct page_cgroup;
@@ -460,7 +461,8 @@ void __mem_cgroup_uncharge_kmem(size_t size);
struct kmem_cache *
__mem_cgroup_get_kmem_cache(struct kmem_cache *cachep, gfp_t gfp);

-#define mem_cgroup_kmem_on 1
+extern struct static_key mem_cgroup_kmem_enabled_key;
+#define mem_cgroup_kmem_on static_key_false(&mem_cgroup_kmem_enabled_key)

void mem_cgroup_destroy_cache(struct kmem_cache *cachep);
#else
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ae61e99..547b632 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -422,6 +422,10 @@ static void mem_cgroup_put(struct mem_cgroup *memcg);
#include <net/sock.h>
#include <net/ip.h>

+struct static_key mem_cgroup_kmem_enabled_key;
+/* so modules can inline the checks */
+EXPORT_SYMBOL(mem_cgroup_kmem_enabled_key);
+
static bool mem_cgroup_is_root(struct mem_cgroup *memcg);
static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, s64 delta);
static void memcg_uncharge_kmem(struct mem_cgroup *memcg, s64 delta);
@@ -468,6 +472,12 @@ void sock_release_memcg(struct sock *sk)
}
}

+static void disarm_static_keys(struct mem_cgroup *memcg)
+{
+ if (memcg->kmem_accounted)
+ static_key_slow_dec(&mem_cgroup_kmem_enabled_key);
+}
+
#ifdef CONFIG_INET
struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
{
@@ -847,6 +857,10 @@ static void memcg_slab_init(struct mem_cgroup *memcg)
for (i = 0; i < MAX_KMEM_CACHE_TYPES; i++)
rcu_assign_pointer(memcg->slabs[i], NULL);
}
+#else
+static inline void disarm_static_keys(struct mem_cgroup *memcg)
+{
+}
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */

static void drain_all_stock_async(struct mem_cgroup *memcg);
@@ -4366,8 +4380,12 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
*
* But it is not worth the trouble
*/
- if (!memcg->kmem_accounted && val != RESOURCE_MAX)
+ mutex_lock(&set_limit_mutex);
+ if (!memcg->kmem_accounted && val != RESOURCE_MAX) {
+ static_key_slow_inc(&mem_cgroup_kmem_enabled_key);
memcg->kmem_accounted = true;
+ }
+ mutex_unlock(&set_limit_mutex);
}
#endif
else
@@ -5349,6 +5367,7 @@ static void __mem_cgroup_put(struct mem_cgroup *memcg, int count)
{
if (atomic_sub_and_test(count, &memcg->refcnt)) {
struct mem_cgroup *parent = parent_mem_cgroup(memcg);
+ disarm_static_keys(memcg);
__mem_cgroup_free(memcg);
if (parent)
mem_cgroup_put(parent);
--
1.7.7.6
Re: [PATCH 00/23] slab+slub accounting for memcg [message #46025 is a reply to message #45989] Sun, 22 April 2012 23:59 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *dsl.telesp.net.br
On 04/20/2012 06:57 PM, Glauber Costa wrote:
> Hi,
>
> This is my current attempt at getting the kmem controller
> into a mergeable state. IMHO, all the important bits are there, and it should't
> change *that* much from now on. I am, however, expecting at least a couple more
> interactions before we sort all the edges out.
>
> This series works for both the slub and the slab. One of my main goals was to
> make sure that the interfaces we are creating actually makes sense for both
> allocators.
>
> I did some adaptations to the slab-specific patches, but the bulk of it
> comes from Suleiman's patches. I did the best to use his patches
> as-is where possible so to keep authorship information. When not possible,
> I tried to be fair and quote it in the commit message.
>
> In this series, all existing caches are created per-memcg after its first hit.
> The main reason is, during discussions in the memory summit we came into
> agreement that the fragmentation problems that could arise from creating all
> of them are mitigated by the typically small quantity of caches in the system
> (order of a few megabytes total for sparsely used caches).
> The lazy creation from Suleiman is kept, although a bit modified. For instance,
> I now use a locked scheme instead of cmpxcgh to make sure cache creation won't
> fail due to duplicates, which simplifies things by quite a bit.
>
> The slub is a bit more complex than what I came up with in my slub-only
> series. The reason is we did not need to use the cache-selection logic
> in the allocator itself - it was done by the cache users. But since now
> we are lazy creating all caches, this is simply no longer doable.
>
> I am leaving destruction of caches out of the series, although most
> of the infrastructure for that is here, since we did it in earlier
> series. This is basically because right now Kame is reworking it for
> user memcg, and I like the new proposed behavior a lot more. We all seemed
> to have agreed that reclaim is an interesting problem by itself, and
> is not included in this already too complicated series. Please note
> that this is still marked as experimental, so we have so room. A proper
> shrinker implementation is a hard requirement to take the kmem controller
> out of the experimental state.
>
> I am also not including documentation, but it should only be a matter
> of merging what we already wrote in earlier series plus some additions.
>
> Glauber Costa (19):
> slub: don't create a copy of the name string in kmem_cache_create
> slub: always get the cache from its page in kfree
> slab: rename gfpflags to allocflags
> slab: use obj_size field of struct kmem_cache when not debugging
> change defines to an enum
> don't force return value checking in res_counter_charge_nofail
> kmem slab accounting basic infrastructure
> slab/slub: struct memcg_params
> slub: consider a memcg parameter in kmem_create_cache
> slab: pass memcg parameter to kmem_cache_create
> slub: create duplicate cache
> slub: provide kmalloc_no_account
> slab: create duplicate cache
> slab: provide kmalloc_no_account
> kmem controller charge/uncharge infrastructure
> slub: charge allocation to a memcg
> slab: per-memcg accounting of slab caches
> memcg: disable kmem code when not in use.
> slub: create slabinfo file for memcg
>
> Suleiman Souhlal (4):
> memcg: Make it possible to use the stock for more than one page.
> memcg: Reclaim when more than one page needed.
> memcg: Track all the memcg children of a kmem_cache.
> memcg: Per-memcg memory.kmem.slabinfo file.
>
> include/linux/memcontrol.h | 87 ++++++
> include/linux/res_counter.h | 2 +-
> include/linux/slab.h | 26 ++
> include/linux/slab_def.h | 77 ++++++-
> include/linux/slub_def.h | 36 +++-
> init/Kconfig | 2 +-
> mm/memcontrol.c | 607 +++++++++++++++++++++++++++++++++++++++++--
> mm/slab.c | 390 +++++++++++++++++++++++-----
> mm/slub.c | 255 ++++++++++++++++--
> 9 files changed, 1364 insertions(+), 118 deletions(-)
>
All patches should be there now.

Sorry for the trouble.
Re: [PATCH 17/23] kmem controller charge/uncharge infrastructure [message #46039 is a reply to message #46021] Mon, 23 April 2012 22:25 Go to previous messageGo to next message
David Rientjes is currently offline  David Rientjes
Messages: 59
Registered: November 2006
Member
From: *parallels.com
On Sun, 22 Apr 2012, Glauber Costa wrote:

> +/*
> + * Return the kmem_cache we're supposed to use for a slab allocation.
> + * If we are in interrupt context or otherwise have an allocation that
> + * can't fail, we return the original cache.
> + * Otherwise, we will try to use the current memcg's version of the cache.
> + *
> + * If the cache does not exist yet, if we are the first user of it,
> + * we either create it immediately, if possible, or create it asynchronously
> + * in a workqueue.
> + * In the latter case, we will let the current allocation go through with
> + * the original cache.
> + *
> + * This function returns with rcu_read_lock() held.
> + */
> +struct kmem_cache *__mem_cgroup_get_kmem_cache(struct kmem_cache *cachep,
> + gfp_t gfp)
> +{
> + struct mem_cgroup *memcg;
> + int idx;
> +
> + gfp |= cachep->allocflags;
> +
> + if ((current->mm == NULL))
> + return cachep;
> +
> + if (cachep->memcg_params.memcg)
> + return cachep;
> +
> + idx = cachep->memcg_params.id;
> + VM_BUG_ON(idx == -1);
> +
> + memcg = mem_cgroup_from_task(current);
> + if (!mem_cgroup_kmem_enabled(memcg))
> + return cachep;
> +
> + if (rcu_access_pointer(memcg->slabs[idx]) == NULL) {
> + memcg_create_cache_enqueue(memcg, cachep);
> + return cachep;
> + }
> +
> + return rcu_dereference(memcg->slabs[idx]);
> +}
> +EXPORT_SYMBOL(__mem_cgroup_get_kmem_cache);
> +
> +void mem_cgroup_remove_child_kmem_cache(struct kmem_cache *cachep, int id)
> +{
> + rcu_assign_pointer(cachep->memcg_params.memcg->slabs[id], NULL);
> +}
> +
> +bool __mem_cgroup_charge_kmem(gfp_t gfp, size_t size)
> +{
> + struct mem_cgroup *memcg;
> + bool ret = true;
> +
> + rcu_read_lock();
> + memcg = mem_cgroup_from_task(current);

This seems horribly inconsistent with memcg charging of user memory since
it charges to p->mm->owner and you're charging to p. So a thread attached
to a memcg can charge user memory to one memcg while charging slab to
another memcg?

> +
> + if (!mem_cgroup_kmem_enabled(memcg))
> + goto out;
> +
> + mem_cgroup_get(memcg);
> + ret = memcg_charge_kmem(memcg, gfp, size) == 0;
> + if (ret)
> + mem_cgroup_put(memcg);
> +out:
> + rcu_read_unlock();
> + return ret;
> +}
> +EXPORT_SYMBOL(__mem_cgroup_charge_kmem);
> +
> +void __mem_cgroup_uncharge_kmem(size_t size)
> +{
> + struct mem_cgroup *memcg;
> +
> + rcu_read_lock();
> + memcg = mem_cgroup_from_task(current);
> +
> + if (!mem_cgroup_kmem_enabled(memcg))
> + goto out;
> +
> + mem_cgroup_put(memcg);
> + memcg_uncharge_kmem(memcg, size);
> +out:
> + rcu_read_unlock();
> +}
> +EXPORT_SYMBOL(__mem_cgroup_uncharge_kmem);
Re: [PATCH 11/23] slub: consider a memcg parameter in kmem_create_cache [message #46050 is a reply to message #46000] Tue, 24 April 2012 14:03 Go to previous messageGo to next message
Frederic Weisbecker is currently offline  Frederic Weisbecker
Messages: 25
Registered: April 2012
Junior Member
From: *parallels.com
On Fri, Apr 20, 2012 at 06:57:19PM -0300, Glauber Costa wrote:
> diff --git a/mm/slub.c b/mm/slub.c
> index 2652e7c..86e40cc 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -32,6 +32,7 @@
> #include <linux/prefetch.h>
>
> #include <trace/events/kmem.h>
> +#include <linux/memcontrol.h>
>
> /*
> * Lock order:
> @@ -3880,7 +3881,7 @@ static int slab_unmergeable(struct kmem_cache *s)
> return 0;
> }
>
> -static struct kmem_cache *find_mergeable(size_t size,
> +static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
> size_t align, unsigned long flags, const char *name,
> void (*ctor)(void *))
> {
> @@ -3916,21 +3917,29 @@ static struct kmem_cache *find_mergeable(size_t size,
> if (s->size - size >= sizeof(void *))
> continue;
>
> + if (memcg && s->memcg_params.memcg != memcg)
> + continue;
> +

This probably won't build without CONFIG_CGROUP_MEM_RES_CTLR_KMEM ?

> return s;
> }
> return NULL;
> }
>
> -struct kmem_cache *kmem_cache_create(const char *name, size_t size,
> - size_t align, unsigned long flags, void (*ctor)(void *))
> +struct kmem_cache *
> +kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size,

Does that build without CONFIG_CGROUP_MEM_RES_CTLR ?

> + size_t align, unsigned long flags, void (*ctor)(void *))
> {
> struct kmem_cache *s;
>
> if (WARN_ON(!name))
> return NULL;
>
> +#ifndef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
> + WARN_ON(memcg != NULL);
> +#endif
> +
> down_write(&slub_lock);
> - s = find_mergeable(size, align, flags, name, ctor);
> + s = find_mergeable(memcg, size, align, flags, name, ctor);
> if (s) {
> s->refcount++;
> /*
> @@ -3954,12 +3963,15 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
> size, align, flags, ctor)) {
> list_add(&s->list, &slab_caches);
> up_write(&slub_lock);
> + mem_cgroup_register_cache(memcg, s);

How do you handle when the memcg cgroup gets destroyed? Also that means only one
memcg cgroup can be accounted for a given slab cache? What if that memcg cgroup has
children? Hmm, perhaps this is handled in a further patch in the series, I saw a
patch title with "children" inside :)

Also my knowledge on memory allocators is near zero, so I may well be asking weird
questions...
Re: [PATCH 13/23] slub: create duplicate cache [message #46051 is a reply to message #46015] Tue, 24 April 2012 14:18 Go to previous messageGo to next message
Frederic Weisbecker is currently offline  Frederic Weisbecker
Messages: 25
Registered: April 2012
Junior Member
From: *parallels.com
On Sun, Apr 22, 2012 at 08:53:30PM -0300, Glauber Costa wrote:
> This patch provides kmem_cache_dup(), that duplicates
> a cache for a memcg, preserving its creation properties.
> Object size, alignment and flags are all respected.
>
> When a duplicate cache is created, the parent cache cannot
> be destructed during the child lifetime. To assure this,
> its reference count is increased if the cache creation
> succeeds.
>
> Signed-off-by: Glauber Costa <glommer@parallels.com>
> CC: Christoph Lameter <cl@linux.com>
> CC: Pekka Enberg <penberg@cs.helsinki.fi>
> CC: Michal Hocko <mhocko@suse.cz>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> CC: Johannes Weiner <hannes@cmpxchg.org>
> CC: Suleiman Souhlal <suleiman@google.com>
> ---
> include/linux/memcontrol.h | 3 +++
> include/linux/slab.h | 3 +++
> mm/memcontrol.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
> mm/slub.c | 37 +++++++++++++++++++++++++++++++++++++
> 4 files changed, 87 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 99e14b9..493ecdd 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -445,6 +445,9 @@ int memcg_css_id(struct mem_cgroup *memcg);
> void mem_cgroup_register_cache(struct mem_cgroup *memcg,
> struct kmem_cache *s);
> void mem_cgroup_release_cache(struct kmem_cache *cachep);
> +extern char *mem_cgroup_cache_name(struct mem_cgroup *memcg,
> + struct kmem_cache *cachep);
> +
> #else
> static inline void mem_cgroup_register_cache(struct mem_cgroup *memcg,
> struct kmem_cache *s)
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index c7a7e05..909b508 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -323,6 +323,9 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
>
> #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
> #define MAX_KMEM_CACHE_TYPES 400
> +extern struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
> + struct kmem_cache *cachep);
> +void kmem_cache_drop_ref(struct kmem_cache *cachep);
> #else
> #define MAX_KMEM_CACHE_TYPES 0
> #endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 0015ed0..e881d83 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -467,6 +467,50 @@ struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
> EXPORT_SYMBOL(tcp_proto_cgroup);
> #endif /* CONFIG_INET */
>
> +/*
> + * This is to prevent races againt the kmalloc cache creations.
> + * Should never be used outside the core memcg code. Therefore,
> + * copy it here, instead of letting it in lib/
> + */
> +static char *kasprintf_no_account(gfp_t gfp, const char *fmt, ...)
> +{
> + unsigned int len;
> + char *p = NULL;
> + va_list ap, aq;
> +
> + va_start(ap, fmt);
> + va_copy(aq, ap);
> + len = vsnprintf(NULL, 0, fmt, aq);
> + va_end(aq);
> +
> + p = kmalloc_no_account(len+1, gfp);

I can't seem to find kmalloc_no_account() in this patch or may be
I missed it in a previous one?

> + if (!p)
> + goto out;
> +
> + vsnprintf(p, len+1, fmt, ap);
> +
> +out:
> + va_end(ap);
> + return p;
> +}
> +
> +char *mem_cgroup_cache_name(struct mem_cgroup *memcg, struct kmem_cache *cachep)
> +{
> + char *name;
> + struct dentry *dentry = memcg->css.cgroup->dentry;
> +
> + BUG_ON(dentry == NULL);
> +
> + /* Preallocate the space for "dead" at the end */
> + name = kasprintf_no_account(GFP_KERNEL, "%s(%d:%s)dead",
> + cachep->name, css_id(&memcg->css), dentry->d_name.name);
> +
> + if (name)
> + /* Remove "dead" */
> + name[strlen(name) - 4] = '\0';

Why this space for "dead" ? I can't seem to find a reference to that in
the kernel. Is it something I'm missing because of my lack of slab knowledge
or is it something needed in a further patch? In which case this should be
explained in the changelog.

> + return name;
> +}
> +
> /* Bitmap used for allocating the cache id numbers. */
> static DECLARE_BITMAP(cache_types, MAX_KMEM_CACHE_TYPES);
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 86e40cc..2285a96 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -3993,6 +3993,43 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
> }
> EXPORT_SYMBOL(kmem_cache_create);
>
> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
> +struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
> + struct kmem_cache *s)
> +{
> + char *name;
> + struct kmem_cache *new;
> +
> + name = mem_cgroup_cache_name(memcg, s);
> + if (!name)
> + return NULL;
> +
> + new = kmem_cache_create_memcg(memcg, name, s->objsize, s->align,
> + s->allocflags, s->ctor);
> +
> + /*
> + * We increase the reference counter in the parent cache, to
> + * prevent it from being deleted. If kmem_cache_destroy() is
> + * called for the root cache before we call it for a child cache,
> + * it will be queued for destruction when we finally drop the
> + * reference on the child cache.
> + */
> + if (new) {
> + down_write(&slub_lock);
> + s->refcount++;
> + up_write(&slub_lock);
> + }
> +
> + return new;
> +}
> +
> +void kmem_cache_drop_ref(struct kmem_cache *s)
> +{
> + BUG_ON(s->memcg_params.id != -1);
> + kmem_cache_destroy(s);
> +}
> +#endif
> +
> #ifdef CONFIG_SMP
> /*
> * Use the cpu notifier to insure that the cpu slabs are flushed when
> --
> 1.7.7.6
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 17/23] kmem controller charge/uncharge infrastructure [message #46052 is a reply to message #46039] Tue, 24 April 2012 14:22 Go to previous messageGo to next message
Frederic Weisbecker is currently offline  Frederic Weisbecker
Messages: 25
Registered: April 2012
Junior Member
From: *parallels.com
On Mon, Apr 23, 2012 at 03:25:59PM -0700, David Rientjes wrote:
> On Sun, 22 Apr 2012, Glauber Costa wrote:
>
> > +/*
> > + * Return the kmem_cache we're supposed to use for a slab allocation.
> > + * If we are in interrupt context or otherwise have an allocation that
> > + * can't fail, we return the original cache.
> > + * Otherwise, we will try to use the current memcg's version of the cache.
> > + *
> > + * If the cache does not exist yet, if we are the first user of it,
> > + * we either create it immediately, if possible, or create it asynchronously
> > + * in a workqueue.
> > + * In the latter case, we will let the current allocation go through with
> > + * the original cache.
> > + *
> > + * This function returns with rcu_read_lock() held.
> > + */
> > +struct kmem_cache *__mem_cgroup_get_kmem_cache(struct kmem_cache *cachep,
> > + gfp_t gfp)
> > +{
> > + struct mem_cgroup *memcg;
> > + int idx;
> > +
> > + gfp |= cachep->allocflags;
> > +
> > + if ((current->mm == NULL))
> > + return cachep;
> > +
> > + if (cachep->memcg_params.memcg)
> > + return cachep;
> > +
> > + idx = cachep->memcg_params.id;
> > + VM_BUG_ON(idx == -1);
> > +
> > + memcg = mem_cgroup_from_task(current);
> > + if (!mem_cgroup_kmem_enabled(memcg))
> > + return cachep;
> > +
> > + if (rcu_access_pointer(memcg->slabs[idx]) == NULL) {
> > + memcg_create_cache_enqueue(memcg, cachep);
> > + return cachep;
> > + }
> > +
> > + return rcu_dereference(memcg->slabs[idx]);
> > +}
> > +EXPORT_SYMBOL(__mem_cgroup_get_kmem_cache);
> > +
> > +void mem_cgroup_remove_child_kmem_cache(struct kmem_cache *cachep, int id)
> > +{
> > + rcu_assign_pointer(cachep->memcg_params.memcg->slabs[id], NULL);
> > +}
> > +
> > +bool __mem_cgroup_charge_kmem(gfp_t gfp, size_t size)
> > +{
> > + struct mem_cgroup *memcg;
> > + bool ret = true;
> > +
> > + rcu_read_lock();
> > + memcg = mem_cgroup_from_task(current);
>
> This seems horribly inconsistent with memcg charging of user memory since
> it charges to p->mm->owner and you're charging to p. So a thread attached
> to a memcg can charge user memory to one memcg while charging slab to
> another memcg?

Charging to the thread rather than the process seem to me the right behaviour:
you can have two threads of a same process attached to different cgroups.

Perhaps it is the user memory memcg that needs to be fixed?

>
> > +
> > + if (!mem_cgroup_kmem_enabled(memcg))
> > + goto out;
> > +
> > + mem_cgroup_get(memcg);
> > + ret = memcg_charge_kmem(memcg, gfp, size) == 0;
> > + if (ret)
> > + mem_cgroup_put(memcg);
> > +out:
> > + rcu_read_unlock();
> > + return ret;
> > +}
> > +EXPORT_SYMBOL(__mem_cgroup_charge_kmem);
> > +
> > +void __mem_cgroup_uncharge_kmem(size_t size)
> > +{
> > + struct mem_cgroup *memcg;
> > +
> > + rcu_read_lock();
> > + memcg = mem_cgroup_from_task(current);
> > +
> > + if (!mem_cgroup_kmem_enabled(memcg))
> > + goto out;
> > +
> > + mem_cgroup_put(memcg);
> > + memcg_uncharge_kmem(memcg, size);
> > +out:
> > + rcu_read_unlock();
> > +}
> > +EXPORT_SYMBOL(__mem_cgroup_uncharge_kmem);
Re: [PATCH 11/23] slub: consider a memcg parameter in kmem_create_cache [message #46053 is a reply to message #46050] Tue, 24 April 2012 14:27 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *virtua.com.br
On 04/24/2012 11:03 AM, Frederic Weisbecker wrote:
> On Fri, Apr 20, 2012 at 06:57:19PM -0300, Glauber Costa wrote:
>> diff --git a/mm/slub.c b/mm/slub.c
>> index 2652e7c..86e40cc 100644
>> --- a/mm/slub.c
>> +++ b/mm/slub.c
>> @@ -32,6 +32,7 @@
>> #include<linux/prefetch.h>
>>
>> #include<trace/events/kmem.h>
>> +#include<linux/memcontrol.h>
>>
>> /*
>> * Lock order:
>> @@ -3880,7 +3881,7 @@ static int slab_unmergeable(struct kmem_cache *s)
>> return 0;
>> }
>>
>> -static struct kmem_cache *find_mergeable(size_t size,
>> +static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
>> size_t align, unsigned long flags, const char *name,
>> void (*ctor)(void *))
>> {
>> @@ -3916,21 +3917,29 @@ static struct kmem_cache *find_mergeable(size_t size,
>> if (s->size - size>= sizeof(void *))
>> continue;
>>
>> + if (memcg&& s->memcg_params.memcg != memcg)
>> + continue;
>> +
>
> This probably won't build without CONFIG_CGROUP_MEM_RES_CTLR_KMEM ?

Probably not, thanks.

>
>> return s;
>> }
>> return NULL;
>> }
>>
>> -struct kmem_cache *kmem_cache_create(const char *name, size_t size,
>> - size_t align, unsigned long flags, void (*ctor)(void *))
>> +struct kmem_cache *
>> +kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size,
>
> Does that build without CONFIG_CGROUP_MEM_RES_CTLR ?
Yes, because MEM_RES_CTLR_KMEM is dependent on RES_CTLR.

>
>> + size_t align, unsigned long flags, void (*ctor)(void *))
>> {
>> struct kmem_cache *s;
>>
>> if (WARN_ON(!name))
>> return NULL;
>>
>> +#ifndef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
>> + WARN_ON(memcg != NULL);
>> +#endif
>> +
>> down_write(&slub_lock);
>> - s = find_mergeable(size, align, flags, name, ctor);
>> + s = find_mergeable(memcg, size, align, flags, name, ctor);
>> if (s) {
>> s->refcount++;
>> /*
>> @@ -3954,12 +3963,15 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
>> size, align, flags, ctor)) {
>> list_add(&s->list,&slab_caches);
>> up_write(&slub_lock);
>> + mem_cgroup_register_cache(memcg, s);
>
> How do you handle when the memcg cgroup gets destroyed?

I don't (yet), because - as mentioned in patch 0 - I decided to hold
those patches until I had a better idea about how would Kame's
pre_destroy() patches look like. I plan, however, to include it in the
next version.

The idea is basically to mark the caches as dead (answers another
question of yours), and wait until it runs out of objects. Talking
specifically about the slub, that happens when free_page() frees the
last page of the cache *and* its reference count goes down to zero
(kmem_cache_destroy() drops the refcnt, so it will mean that cgroup
destruction already called it)

When we have a shrinker - I don't plan to include a per-memcg shrinker
in the first merge, because let's face it, it is a hard problem in
itself that would be better thought separately - we can call the
shrinkers to force the objects to die earlier.

> Also that means only one
> memcg cgroup can be accounted for a given slab cache?

Not sure if I understand your question in an ambiguity-free way.
If you mean the situation in which two tasks touch the same object, then
yes, only one of them is accounted.

If you mean about types of cache, then no, each memcg can have it's own
version of the whole cache array.


> What if that memcg cgroup has
> children? Hmm, perhaps this is handled in a further patch in the series, I saw a
> patch title with "children" inside :)

then the children creates caches as well, as much as the parents.

Note that because of the delayed allocation mechanism, if the parent
serves only as a placeholder, and has no tasks inside it, then it will
never touch - and therefore never create - any cache.
Re: [PATCH 13/23] slub: create duplicate cache [message #46054 is a reply to message #46051] Tue, 24 April 2012 14:37 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *virtua.com.br
On 04/24/2012 11:18 AM, Frederic Weisbecker wrote:
> On Sun, Apr 22, 2012 at 08:53:30PM -0300, Glauber Costa wrote:
>> This patch provides kmem_cache_dup(), that duplicates
>> a cache for a memcg, preserving its creation properties.
>> Object size, alignment and flags are all respected.
>>
>> When a duplicate cache is created, the parent cache cannot
>> be destructed during the child lifetime. To assure this,
>> its reference count is increased if the cache creation
>> succeeds.
>>
>> Signed-off-by: Glauber Costa<glommer@parallels.com>
>> CC: Christoph Lameter<cl@linux.com>
>> CC: Pekka Enberg<penberg@cs.helsinki.fi>
>> CC: Michal Hocko<mhocko@suse.cz>
>> CC: Kamezawa Hiroyuki<kamezawa.hiroyu@jp.fujitsu.com>
>> CC: Johannes Weiner<hannes@cmpxchg.org>
>> CC: Suleiman Souhlal<suleiman@google.com>
>> ---
>> include/linux/memcontrol.h | 3 +++
>> include/linux/slab.h | 3 +++
>> mm/memcontrol.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>> mm/slub.c | 37 +++++++++++++++++++++++++++++++++++++
>> 4 files changed, 87 insertions(+), 0 deletions(-)
>>
>> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
>> index 99e14b9..493ecdd 100644
>> --- a/include/linux/memcontrol.h
>> +++ b/include/linux/memcontrol.h
>> @@ -445,6 +445,9 @@ int memcg_css_id(struct mem_cgroup *memcg);
>> void mem_cgroup_register_cache(struct mem_cgroup *memcg,
>> struct kmem_cache *s);
>> void mem_cgroup_release_cache(struct kmem_cache *cachep);
>> +extern char *mem_cgroup_cache_name(struct mem_cgroup *memcg,
>> + struct kmem_cache *cachep);
>> +
>> #else
>> static inline void mem_cgroup_register_cache(struct mem_cgroup *memcg,
>> struct kmem_cache *s)
>> diff --git a/include/linux/slab.h b/include/linux/slab.h
>> index c7a7e05..909b508 100644
>> --- a/include/linux/slab.h
>> +++ b/include/linux/slab.h
>> @@ -323,6 +323,9 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
>>
>> #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
>> #define MAX_KMEM_CACHE_TYPES 400
>> +extern struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
>> + struct kmem_cache *cachep);
>> +void kmem_cache_drop_ref(struct kmem_cache *cachep);
>> #else
>> #define MAX_KMEM_CACHE_TYPES 0
>> #endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index 0015ed0..e881d83 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -467,6 +467,50 @@ struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
>> EXPORT_SYMBOL(tcp_proto_cgroup);
>> #endif /* CONFIG_INET */
>>
>> +/*
>> + * This is to prevent races againt the kmalloc cache creations.
>> + * Should never be used outside the core memcg code. Therefore,
>> + * copy it here, instead of letting it in lib/
>> + */
>> +static char *kasprintf_no_account(gfp_t gfp, const char *fmt, ...)
>> +{
>> + unsigned int len;
>> + char *p = NULL;
>> + va_list ap, aq;
>> +
>> + va_start(ap, fmt);
>> + va_copy(aq, ap);
>> + len = vsnprintf(NULL, 0, fmt, aq);
>> + va_end(aq);
>> +
>> + p = kmalloc_no_account(len+1, gfp);
>
> I can't seem to find kmalloc_no_account() in this patch or may be
> I missed it in a previous one?

It is in a previous one (actually two, one for the slab, one for the
slub). They are bundled in the cache creation, but I could separate it
for clarity, if you prefer.


>> + if (!p)
>> + goto out;
>> +
>> + vsnprintf(p, len+1, fmt, ap);
>> +
>> +out:
>> + va_end(ap);
>> + return p;
>> +}
>> +
>> +char *mem_cgroup_cache_name(struct mem_cgroup *memcg, struct kmem_cache *cachep)
>> +{
>> + char *name;
>> + struct dentry *dentry = memcg->css.cgroup->dentry;
>> +
>> + BUG_ON(dentry == NULL);
>> +
>> + /* Preallocate the space for "dead" at the end */
>> + name = kasprintf_no_account(GFP_KERNEL, "%s(%d:%s)dead",
>> + cachep->name, css_id(&memcg->css), dentry->d_name.name);
>> +
>> + if (name)
>> + /* Remove "dead" */
>> + name[strlen(name) - 4] = '\0';
>
> Why this space for "dead" ?

Ok, sorry. Since I didn't include the destruction part, it got too easy
for whoever wasn't following the last discussion on this to get lost -
My bad. So here it is:

When we destroy the memcg, some objects may still hold the cache in
memory. It is like a reference count, in a sense, which each object
being a reference.

In typical cases, like non-shrinkable caches that has create - destroy
patterns, the caches will go away as soon as the tasks using them.

But in cache-like structure like the dentry cache, the objects may hang
around until a shrinker pass takes them out. And even then, some of them
will live on.

In this case, we will display them with "dead" in the name.

We could hide them, but then it gets weirder because it would be hard to
understand where is your used memory when you need to inspect your system.

Creating another file, slabinfo_deadcaches, and keeping the names, is
also a possibility, if people think that the string append is way too ugly.
Re: [PATCH 17/23] kmem controller charge/uncharge infrastructure [message #46055 is a reply to message #46052] Tue, 24 April 2012 14:40 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *virtua.com.br
On 04/24/2012 11:22 AM, Frederic Weisbecker wrote:
> On Mon, Apr 23, 2012 at 03:25:59PM -0700, David Rientjes wrote:
>> On Sun, 22 Apr 2012, Glauber Costa wrote:
>>
>>> +/*
>>> + * Return the kmem_cache we're supposed to use for a slab allocation.
>>> + * If we are in interrupt context or otherwise have an allocation that
>>> + * can't fail, we return the original cache.
>>> + * Otherwise, we will try to use the current memcg's version of the cache.
>>> + *
>>> + * If the cache does not exist yet, if we are the first user of it,
>>> + * we either create it immediately, if possible, or create it asynchronously
>>> + * in a workqueue.
>>> + * In the latter case, we will let the current allocation go through with
>>> + * the original cache.
>>> + *
>>> + * This function returns with rcu_read_lock() held.
>>> + */
>>> +struct kmem_cache *__mem_cgroup_get_kmem_cache(struct kmem_cache *cachep,
>>> + gfp_t gfp)
>>> +{
>>> + struct mem_cgroup *memcg;
>>> + int idx;
>>> +
>>> + gfp |= cachep->allocflags;
>>> +
>>> + if ((current->mm == NULL))
>>> + return cachep;
>>> +
>>> + if (cachep->memcg_params.memcg)
>>> + return cachep;
>>> +
>>> + idx = cachep->memcg_params.id;
>>> + VM_BUG_ON(idx == -1);
>>> +
>>> + memcg = mem_cgroup_from_task(current);
>>> + if (!mem_cgroup_kmem_enabled(memcg))
>>> + return cachep;
>>> +
>>> + if (rcu_access_pointer(memcg->slabs[idx]) == NULL) {
>>> + memcg_create_cache_enqueue(memcg, cachep);
>>> + return cachep;
>>> + }
>>> +
>>> + return rcu_dereference(memcg->slabs[idx]);
>>> +}
>>> +EXPORT_SYMBOL(__mem_cgroup_get_kmem_cache);
>>> +
>>> +void mem_cgroup_remove_child_kmem_cache(struct kmem_cache *cachep, int id)
>>> +{
>>> + rcu_assign_pointer(cachep->memcg_params.memcg->slabs[id], NULL);
>>> +}
>>> +
>>> +bool __mem_cgroup_charge_kmem(gfp_t gfp, size_t size)
>>> +{
>>> + struct mem_cgroup *memcg;
>>> + bool ret = true;
>>> +
>>> + rcu_read_lock();
>>> + memcg = mem_cgroup_from_task(current);
>>
>> This seems horribly inconsistent with memcg charging of user memory since
>> it charges to p->mm->owner and you're charging to p. So a thread attached
>> to a memcg can charge user memory to one memcg while charging slab to
>> another memcg?
>
> Charging to the thread rather than the process seem to me the right behaviour:
> you can have two threads of a same process attached to different cgroups.
>
> Perhaps it is the user memory memcg that needs to be fixed?
>

Hi David,

I just saw all the answers, so I will bundle here since Frederic also
chimed in...

I think memcg is not necessarily wrong. That is because threads in a
process share an address space, and you will eventually need to map a
page to deliver it to userspace. The mm struct points you to the owner
of that.

But that is not necessarily true for things that live in the kernel
address space.

Do you view this differently ?
Re: [PATCH 17/23] kmem controller charge/uncharge infrastructure [message #46061 is a reply to message #46052] Tue, 24 April 2012 20:21 Go to previous messageGo to next message
David Rientjes is currently offline  David Rientjes
Messages: 59
Registered: November 2006
Member
From: *parallels.com
On Tue, 24 Apr 2012, Frederic Weisbecker wrote:

> > This seems horribly inconsistent with memcg charging of user memory since
> > it charges to p->mm->owner and you're charging to p. So a thread attached
> > to a memcg can charge user memory to one memcg while charging slab to
> > another memcg?
>
> Charging to the thread rather than the process seem to me the right behaviour:
> you can have two threads of a same process attached to different cgroups.
>
> Perhaps it is the user memory memcg that needs to be fixed?
>

No, because memory is represented by mm_struct, not task_struct, so you
must charge to p->mm->owner to allow for moving threads amongst memcgs
later for memory.move_charge_at_immigrate. You shouldn't be able to
charge two different memcgs for memory represented by a single mm.

> > > +
> > > + if (!mem_cgroup_kmem_enabled(memcg))
> > > + goto out;
> > > +
> > > + mem_cgroup_get(memcg);
> > > + ret = memcg_charge_kmem(memcg, gfp, size) == 0;
> > > + if (ret)
> > > + mem_cgroup_put(memcg);
> > > +out:
> > > + rcu_read_unlock();
> > > + return ret;
> > > +}
> > > +EXPORT_SYMBOL(__mem_cgroup_charge_kmem);
> > > +
> > > +void __mem_cgroup_uncharge_kmem(size_t size)
> > > +{
> > > + struct mem_cgroup *memcg;
> > > +
> > > + rcu_read_lock();
> > > + memcg = mem_cgroup_from_task(current);
> > > +
> > > + if (!mem_cgroup_kmem_enabled(memcg))
> > > + goto out;
> > > +
> > > + mem_cgroup_put(memcg);
> > > + memcg_uncharge_kmem(memcg, size);
> > > +out:
> > > + rcu_read_unlock();
> > > +}
> > > +EXPORT_SYMBOL(__mem_cgroup_uncharge_kmem);
Re: [PATCH 17/23] kmem controller charge/uncharge infrastructure [message #46062 is a reply to message #46055] Tue, 24 April 2012 20:25 Go to previous messageGo to next message
David Rientjes is currently offline  David Rientjes
Messages: 59
Registered: November 2006
Member
From: *parallels.com
On Tue, 24 Apr 2012, Glauber Costa wrote:

> I think memcg is not necessarily wrong. That is because threads in a process
> share an address space, and you will eventually need to map a page to deliver
> it to userspace. The mm struct points you to the owner of that.
>
> But that is not necessarily true for things that live in the kernel address
> space.
>
> Do you view this differently ?
>

Yes, for user memory, I see charging to p->mm->owner as allowing that
process to eventually move and be charged to a different memcg and there's
no way to do proper accounting if the charge is split amongst different
memcgs because of thread membership to a set of memcgs. This is
consistent with charges for shared memory being moved when a thread
mapping it moves to a new memcg, as well.
Re: [PATCH 17/23] kmem controller charge/uncharge infrastructure [message #46063 is a reply to message #46062] Tue, 24 April 2012 21:36 Go to previous messageGo to next message
Glauber Costa is currently offline  Glauber Costa
Messages: 916
Registered: October 2011
Senior Member
From: *virtua.com.br
On 04/24/2012 05:25 PM, David Rientjes wrote:
> On Tue, 24 Apr 2012, Glauber Costa wrote:
>
>> I think memcg is not necessarily wrong. That is because threads in a process
>> share an address space, and you will eventually need to map a page to deliver
>> it to userspace. The mm struct points you to the owner of that.
>>
>> But that is not necessarily true for things that live in the kernel address
>> space.
>>
>> Do you view this differently ?
>>
>
> Yes, for user memory, I see charging to p->mm->owner as allowing that
> process to eventually move and be charged to a different memcg and there's
> no way to do proper accounting if the charge is split amongst different
> memcgs because of thread membership to a set of memcgs. This is
> consistent with charges for shared memory being moved when a thread
> mapping it moves to a new memcg, as well.

But that's the problem.

When we are dealing with kernel memory, we are allocating a whole slab
page. It is essentially impossible to track, given a page, which task
allocated which object.
Re: [PATCH 17/23] kmem controller charge/uncharge infrastructure [message #46064 is a reply to message #46063] Tue, 24 April 2012 22:54 Go to previous messageGo to next message
David Rientjes is currently offline  David Rientjes
Messages: 59
Registered: November 2006
Member
From: *parallels.com
On Tue, 24 Apr 2012, Glauber Costa wrote:

> > Yes, for user memory, I see charging to p->mm->owner as allowing that
> > process to eventually move and be charged to a different memcg and there's
> > no way to do proper accounting if the charge is split amongst different
> > memcgs because of thread membership to a set of memcgs. This is
> > consistent with charges for shared memory being moved when a thread
> > mapping it moves to a new memcg, as well.
>
> But that's the problem.
>
> When we are dealing with kernel memory, we are allocating a whole slab page.
> It is essentially impossible to track, given a page, which task allocated
> which object.
>

Right, so you have to make the distinction that slab charges cannot be
migrated by memory.move_charge_at_immigrate (and it's not even specified
to do anything beyond user pages in Documentation/cgroups/memory.txt), but
it would be consistent to charge the same memcg for a process's slab
allocations as the process's user allocations.

My response was why we shouldn't be charging user pages to
mem_cgroup_from_task(current) rather than
mem_cgroup_from_task(current->mm->owner) which is what is currently
implemented.

If that can't be changed so that we can still migrate user memory amongst
memcgs for memory.move_charge_at_immigrate, then it seems consistent to
have all allocations done by a task to be charged to the same memcg.
Hence, I suggested current->mm->owner for slab charging as well.
Re: [PATCH 04/23] memcg: Make it possible to use the stock for more than one page. [message #46066 is a reply to message #45991] Wed, 25 April 2012 00:59 Go to previous messageGo to next message
KAMEZAWA Hiroyuki is currently offline  KAMEZAWA Hiroyuki
Messages: 463
Registered: September 2006
Senior Member
From: *parallels.com
(2012/04/21 6:57), Glauber Costa wrote:

> From: Suleiman Souhlal <ssouhlal@FreeBSD.org>
>
> Signed-off-by: Suleiman Souhlal <suleiman@google.com>


ok, should work enough.

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Re: [PATCH 05/23] memcg: Reclaim when more than one page needed. [message #46067 is a reply to message #45994] Wed, 25 April 2012 01:16 Go to previous messageGo to next message
KAMEZAWA Hiroyuki is currently offline  KAMEZAWA Hiroyuki
Messages: 463
Registered: September 2006
Senior Member
From: *parallels.com
(2012/04/21 6:57), Glauber Costa wrote:

> From: Suleiman Souhlal <ssouhlal@FreeBSD.org>
>
> mem_cgroup_do_charge() was written before slab accounting, and expects
> three cases: being called for 1 page, being called for a stock of 32 pages,
> or being called for a hugepage. If we call for 2 pages (and several slabs
> used in process creation are such, at least with the debug options I had),
> it assumed it's being called for stock and just retried without reclaiming.
>
> Fix that by passing down a minsize argument in addition to the csize.
>
> And what to do about that (csize == PAGE_SIZE && ret) retry? If it's
> needed at all (and presumably is since it's there, perhaps to handle
> races), then it should be extended to more than PAGE_SIZE, yet how far?


IIRC, it was for preventing rapid OOM kill and reducing latency.

> And should there be a retry count limit, of what? For now retry up to
> COSTLY_ORDER (as page_alloc.c does), stay safe with a cond_resched(),
> and make sure not to do it if __GFP_NORETRY.
>
> Signed-off-by: Suleiman Souhlal <suleiman@google.com>


Hmm, maybe ok.

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>


> ---
> mm/memcontrol.c | 18 +++++++++++-------
> 1 files changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 4b94b2d..cbffc4c 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2187,7 +2187,8 @@ enum {
> };
>
> static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
> - unsigned int nr_pages, bool oom_check)
> + unsigned int nr_pages, unsigned int min_pages,
> + bool oom_check)
> {
> unsigned long csize = nr_pages * PAGE_SIZE;
> struct mem_cgroup *mem_over_limit;
> @@ -2210,18 +2211,18 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
> } else
> mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
> /*
> - * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
> - * of regular pages (CHARGE_BATCH), or a single regular page (1).
> - *
> * Never reclaim on behalf of optional batching, retry with a
> * single page instead.
> */
> - if (nr_pages == CHARGE_BATCH)
> + if (nr_pages > min_pages)
> return CHARGE_RETRY;
>
> if (!(gfp_mask & __GFP_WAIT))
> return CHARGE_WOULDBLOCK;
>
> + if (gfp_mask & __GFP_NORETRY)
> + return CHARGE_NOMEM;
> +
> ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
> if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
> return CHARGE_RETRY;
> @@ -2234,8 +2235,10 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
> * unlikely to succeed so close to the limit, and we fall back
> * to regular pages anyway in case of failure.
> */
> - if (nr_pages == 1 && ret)
> + if (nr_pages <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER) && ret) {
> + cond_resched();
> return CHARGE_RETRY;
> + }
>
> /*
> * At task move, charge accounts can be doubly counted. So, it's
> @@ -2369,7 +2372,8 @@ again:
> nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
> }
>
> - ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, oom_check);
> + ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, nr_pages,
> + oom_check);
> switch (ret) {
> case CHARGE_OK:
> break;
Re: [PATCH 07/23] change defines to an enum [message #46068 is a reply to message #45993] Wed, 25 April 2012 01:18 Go to previous messageGo to next message
KAMEZAWA Hiroyuki is currently offline  KAMEZAWA Hiroyuki
Messages: 463
Registered: September 2006
Senior Member
From: *parallels.com
(2012/04/21 6:57), Glauber Costa wrote:

> This is just a cleanup patch for clarity of expression.
> In earlier submissions, people asked it to be in a separate
> patch, so here it is.
>
> Signed-off-by: Glauber Costa <glommer@parallels.com>
> CC: Michal Hocko <mhocko@suse.cz>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> CC: Johannes Weiner <hannes@cmpxchg.org>


Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Re: [PATCH 08/23] don't force return value checking in res_counter_charge_nofail [message #46069 is a reply to message #45996] Wed, 25 April 2012 01:28 Go to previous messageGo to previous message
KAMEZAWA Hiroyuki is currently offline  KAMEZAWA Hiroyuki
Messages: 463
Registered: September 2006
Senior Member
From: *parallels.com
(2012/04/21 6:57), Glauber Costa wrote:

> Since we will succeed with the allocation no matter what, there
> isn't the need to use __must_check with it. It can very well
> be optional.
>
> Signed-off-by: Glauber Costa <glommer@parallels.com>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> CC: Johannes Weiner <hannes@cmpxchg.org>
> CC: Michal Hocko <mhocko@suse.cz>


Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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