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| Re: [PATCH] cgroup: prefer [kv]zalloc over [kv]malloc+memset in memory controller code. [message #41963 is a reply to message #41900] |
Mon, 01 November 2010 19:59  |
Jesper Juhl
Messages: 7
Registered: October 2010
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Junior Member |
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On Mon, 1 Nov 2010, Johannes Weiner wrote:
> On Mon, Nov 01, 2010 at 08:40:56PM +0100, Jesper Juhl wrote:
> > Hi (please CC me on replies),
> >
> >
> > Apologies to those who receive this multiple times. I screwed up the To:
> > field in my original mail :-(
> >
> >
> > In mem_cgroup_alloc() we currently do either kmalloc() or vmalloc() then
> > followed by memset() to zero the memory. This can be more efficiently
> > achieved by using kzalloc() and vzalloc().
> >
> >
> > Signed-off-by: Jesper Juhl <jj@chaosbits.net>
>
> Looks good to me, but there is also the memset after kmalloc in
> alloc_mem_cgroup_per_zone_info().
Dang, I missed that one. Thanks for pointing it out.
Hmm, I'm wondering if we should perhaps add kzalloc_node()/vzalloc_node()
just like kzalloc() and vzalloc()..
> Can you switch that over as well in
> this patch? You can pass __GFP_ZERO to kmalloc_node() for zeroing.
>
Sure thing.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
---
memcontrol.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9a99cfa..bc32ffe 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4169,13 +4169,11 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
*/
if (!node_state(node, N_NORMAL_MEMORY))
tmp = -1;
- pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
+ pn = kmalloc_node(sizeof(*pn), GFP_KERNEL|__GFP_ZERO, tmp);
if (!pn)
return 1;
mem->info.nodeinfo[node] = pn;
- memset(pn, 0, sizeof(*pn));
-
for (zone = 0; zone < MAX_NR_ZONES; zone++) {
mz = &pn->zoneinfo[zone];
for_each_lru(l)
@@ -4199,14 +4197,13 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
/* Can be very big if MAX_NUMNODES is very big */
if (size < PAGE_SIZE)
- mem = kmalloc(size, GFP_KERNEL);
+ mem = kzalloc(size, GFP_KERNEL);
else
- mem = vmalloc(size);
+ mem = vzalloc(size);
if (!mem)
return NULL;
- memset(mem, 0, size);
mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
if (!mem->stat) {
if (size < PAGE_SIZE)
--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Plain text mails only, please http://www.expita.com/nomime.html
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
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