Home » Mailing lists » Devel » [PATCH] cfq: get rid of cfqq hash
| [PATCH] cfq: get rid of cfqq hash [message #12299] |
Tue, 24 April 2007 13:53  |
Vasily Tarasov
Messages: 1345
Registered: January 2006
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Senior Member |
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From: Vasily Tarasov <vtaras@openvz.org>
cfq hash is no more necessary. We always can get cfqq from io context.
cfq_get_io_context_noalloc() function is introduced, because we don't want to
allocate cic on merging and checking may_queue.
In order to identify sync queue we've used hash key = CFQ_KEY_ASYNC. Since hash
is eliminated we need to use other criterion: sync flag for queue is added.
In all places where we dig in rb_tree we're in current context, so no
additional locking is required.
Advantages of this patch: no additional memory for hash, no seeking in hash,
code is cleaner. But it is necessary now to seek cic in per-ioc rbtree, but
it is faster:
- most processes work only with few devices
- most systems have only few block devices
- it is a rb-tree
Signed-off-by: Vasily Tarasov <vtaras@openvz.org>
---
block/cfq-iosched.c | 152 +++++++++++++++++-----------------------------------
1 files changed, 52 insertions(+), 100 deletions(-)
--- linux-2.6.21-rc7-git6/block/cfq-iosched.c.hashrm 2007-04-24 16:40:45.000000000 +0400
+++ linux-2.6.21-rc7-git6/block/cfq-iosched.c 2007-04-24 17:17:41.000000000 +0400
@@ -9,7 +9,6 @@
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/elevator.h>
-#include <linux/hash.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
@@ -29,15 +28,6 @@ static int cfq_slice_idle = HZ / 125;
#define CFQ_IDLE_GRACE (HZ / 10)
#define CFQ_SLICE_SCALE (5)
-#define CFQ_KEY_ASYNC (0)
-
-/*
- * for the hash of cfqq inside the cfqd
- */
-#define CFQ_QHASH_SHIFT 6
-#define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT)
-#define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash)
-
#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
#define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private)
@@ -59,11 +49,6 @@ static struct completion *ioc_gone;
#define cfq_cfqq_dispatched(cfqq) \
((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
-#define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
-
-#define cfq_cfqq_sync(cfqq) \
- (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
-
#define sample_valid(samples) ((samples) > 80)
/*
@@ -81,11 +66,6 @@ struct cfq_data {
struct list_head idle_rr;
unsigned int busy_queues;
- /*
- * cfqq lookup hash
- */
- struct hlist_head *cfq_hash;
-
int rq_in_driver;
int hw_tag;
@@ -127,10 +107,6 @@ struct cfq_queue {
atomic_t ref;
/* parent cfq_data */
struct cfq_data *cfqd;
- /* cfqq lookup hash */
- struct hlist_node cfq_hash;
- /* hash key */
- unsigned int key;
/* member of the rr/busy/cur/idle cfqd list */
struct list_head cfq_list;
/* sorted list of pending requests */
@@ -172,6 +148,7 @@ enum cfqq_state_flags {
CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */
CFQ_CFQQ_FLAG_queue_new, /* queue never been serviced */
CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */
+ CFQ_CFQQ_FLAG_sync, /* synchronous queue */
};
#define CFQ_CFQQ_FNS(name) \
@@ -198,11 +175,14 @@ CFQ_CFQQ_FNS(idle_window);
CFQ_CFQQ_FNS(prio_changed);
CFQ_CFQQ_FNS(queue_new);
CFQ_CFQQ_FNS(slice_new);
+CFQ_CFQQ_FNS(sync);
#undef CFQ_CFQQ_FNS
-static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
+static struct cfq_io_context *
+cfq_get_io_context_noalloc(struct cfq_data *, struct task_struct *);
static void cfq_dispatch_insert(request_queue_t *, struct request *);
-static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);
+static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd,
+ int is_sync, struct task_struct *tsk, gfp_t gfp_mask);
/*
* scheduler run of queue, if there are requests pending and no one in the
@@ -221,17 +201,6 @@ static int cfq_queue_empty(request_queue
return !cfqd->busy_queues;
}
-static inline pid_t cfq_queue_pid(struct task_struct *task, int rw, int is_sync)
-{
- /*
- * Use the per-process queue, for read requests and syncronous writes
- */
- if (!(rw & REQ_RW) || is_sync)
- return task->pid;
-
- return CFQ_KEY_ASYNC;
-}
-
/*
* Scale schedule slice based on io priority. Use the sync time slice only
* if a queue is marked sync and has sync io queued. A sync queue with async
@@ -445,7 +414,7 @@ static void cfq_resort_rr_list(struct cf
n = n->next;
}
list_add_tail(&cfqq->cfq_list, n);
- } else if (!cfq_cfqq_class_sync(cfqq)) {
+ } else if (!cfq_cfqq_sync(cfqq)) {
/*
* async queue always goes to the end. this wont be overly
* unfair to writes, as the sort of the sync queue wont be
@@ -463,7 +432,7 @@ static void cfq_resort_rr_list(struct cf
while ((n = n->prev) != list) {
struct cfq_queue *__cfqq = list_entry_cfqq(n);
- if (!cfq_cfqq_class_sync(cfqq) || !__cfqq->service_last)
+ if (!cfq_cfqq_sync(cfqq) || !__cfqq->service_last)
break;
if (time_before(__cfqq->service_last, cfqq->service_last))
break;
@@ -546,10 +515,14 @@ static struct request *
cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
{
struct task_struct *tsk = current;
- pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio), bio_sync(bio));
+ struct cfq_io_context *cic;
struct cfq_queue *cfqq;
- cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
+ cic = cfq_get_io_context_noalloc(cfqd, tsk);
+ if (!cic)
+ return NULL;
+
+ cfqq = cic->cfqq[bio_sync(bio)];
if (cfqq) {
sector_t sector = bio->bi_sector + bio_sectors(bio);
@@ -642,9 +615,8 @@ static int cfq_allow_merge(request_queue
struct bio *bio)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- const int rw = bio_data_dir(bio);
+ struct cfq_io_context *cic;
struct cfq_queue *cfqq;
- pid_t key;
/*
* Disallow merge of a sync bio into an async request.
@@ -656,9 +628,11 @@ static int cfq_allow_merge(request_queue
* Lookup the cfqq that this bio will be queued with. Allow
* merge only if rq is queued there.
*/
- key = cfq_queue_pid(current, rw, bio_sync(bio));
- cfqq = cfq_find_cfq_hash(cfqd, key, current->ioprio);
+ cic = cfq_get_io_context_noalloc(cfqd, current);
+ if (!cic)
+ return 0;
+ cfqq = cic->cfqq[bio_sync(bio)];
if (cfqq == RQ_CFQQ(rq))
return 1;
@@ -889,7 +863,7 @@ static inline struct request *cfq_check_
if (list_empty(&cfqq->fifo))
return NULL;
- fifo = cfq_cfqq_class_sync(cfqq);
+ fifo = cfq_cfqq_sync(cfqq);
rq = rq_entry_fifo(cfqq->fifo.next);
if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
@@ -934,7 +908,7 @@ static struct cfq_queue *cfq_select_queu
else if (cfq_cfqq_slice_new(cfqq) || cfq_cfqq_dispatched(cfqq)) {
cfqq = NULL;
goto keep_queue;
- } else if (cfq_cfqq_class_sync(cfqq)) {
+ } else if (cfq_cfqq_sync(cfqq)) {
if (cfq_arm_slice_timer(cfqd))
return NULL;
}
@@ -1107,37 +1081,12 @@ static void cfq_put_queue(struct cfq_que
}
/*
- * it's on the empty list and still hashed
+ * it's on the empty list
*/
list_del(&cfqq->cfq_list);
- hlist_del(&cfqq->cfq_hash);
kmem_cache_free(cfq_pool, cfqq);
}
-static struct cfq_queue *
-__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio,
- const int hashval)
-{
- struct hlist_head *hash_list = &cfqd->cfq_hash[hashval];
- struct hlist_node *entry;
- struct cfq_queue *__cfqq;
-
- hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) {
- const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio);
-
- if (__cfqq->key == key && (__p == prio || !prio))
- return __cfqq;
- }
-
- return NULL;
-}
-
-static struct cfq_queue *
-cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio)
-{
- return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT));
-}
-
static void cfq_free_io_context(struct io_context *ioc)
{
struct cfq_io_context *__cic;
@@ -1297,7 +1246,7 @@ static inline void changed_ioprio(struct
cfqq = cic->cfqq[ASYNC];
if (cfqq) {
struct cfq_queue *new_cfqq;
- new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task,
+ new_cfqq = cfq_get_queue(cfqd, ASYNC, cic->ioc->task,
GFP_ATOMIC);
if (new_cfqq) {
cic->cfqq[ASYNC] = new_cfqq;
@@ -1329,16 +1278,16 @@ static void cfq_ioc_set_ioprio(struct io
}
static struct cfq_queue *
-cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
+cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct task_struct *tsk,
gfp_t gfp_mask)
{
- const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
struct cfq_queue *cfqq, *new_cfqq = NULL;
- unsigned short ioprio;
+ struct cfq_io_context *cic;
retry:
- ioprio = tsk->ioprio;
- cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
+ cic = cfq_get_io_context_noalloc(cfqd, tsk);
+ /* cic always exists here */
+ cfqq = cic->cfqq[is_sync];
if (!cfqq) {
if (new_cfqq) {
@@ -1363,20 +1312,19 @@ retry:
memset(cfqq, 0, sizeof(*cfqq));
- INIT_HLIST_NODE(&cfqq->cfq_hash);
INIT_LIST_HEAD(&cfqq->cfq_list);
INIT_LIST_HEAD(&cfqq->fifo);
- cfqq->key = key;
- hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
atomic_set(&cfqq->ref, 0);
cfqq->cfqd = cfqd;
- if (key != CFQ_KEY_ASYNC)
+ if (is_sync)
cfq_mark_cfqq_idle_window(cfqq);
cfq_mark_cfqq_prio_changed(cfqq);
cfq_mark_cfqq_queue_new(cfqq);
+ if (is_sync)
+ cfq_mark_cfqq_sync(cfqq);
cfq_init_prio_data(cfqq);
}
@@ -1506,6 +1454,19 @@ err:
return NULL;
}
+static struct cfq_io_context *
+cfq_get_io_context_noalloc(struct cfq_data *cfqd, struct task_struct *tsk)
+{
+ struct cfq_io_context *cic = NULL;
+ struct io_context *ioc;
+
+ ioc = tsk->io_context;
+ if (ioc)
+ cic = cfq_cic_rb_lookup(cfqd, ioc);
+
+ return cic;
...
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| Re: [PATCH] cfq: get rid of cfqq hash [message #12309 is a reply to message #12299] |
Tue, 24 April 2007 17:02  |
Jens Axboe
Messages: 30
Registered: October 2006
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Member |
|
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On Tue, Apr 24 2007, Vasily Tarasov wrote:
> From: Vasily Tarasov <vtaras@openvz.org>
>
> cfq hash is no more necessary. We always can get cfqq from io context.
> cfq_get_io_context_noalloc() function is introduced, because we don't want to
> allocate cic on merging and checking may_queue.
> In order to identify sync queue we've used hash key = CFQ_KEY_ASYNC. Since hash
> is eliminated we need to use other criterion: sync flag for queue is added.
> In all places where we dig in rb_tree we're in current context, so no
> additional locking is required.
>
> Advantages of this patch: no additional memory for hash, no seeking in hash,
> code is cleaner. But it is necessary now to seek cic in per-ioc rbtree, but
> it is faster:
> - most processes work only with few devices
> - most systems have only few block devices
> - it is a rb-tree
Vasily, this is still not against the CFQ branch, I get tons of rejects:
axboe@nelson:/src/linux-2.6-block $ patch -p1 --dry-run < ~/foo
[...]
10 out of 27 hunks FAILED -- saving rejects to file
block/cfq-iosched.c.rej
If you don't want to use the git tree, then just grab
http://brick.kernel.dk/snaps/cfq-update-20070424
and apply it to 2.6.21-rc7-gitX (latest) and provide a diff against
that. Thanks!
--
Jens Axboe
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| Re: [PATCH] cfq: get rid of cfqq hash [message #12320 is a reply to message #12299] |
Wed, 25 April 2007 06:58 |
Jens Axboe
Messages: 30
Registered: October 2006
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Member |
|
|
On Tue, Apr 24 2007, Vasily Tarasov wrote:
> @@ -1806,7 +1765,11 @@ static int cfq_may_queue(request_queue_t
> * so just lookup a possibly existing queue, or return 'may queue'
> * if that fails
> */
> - cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
> + cic = cfq_get_io_context_noalloc(cfqd, tsk);
> + if (!cic)
> + return ELV_MQUEUE_MAY;
> +
> + cfqq = cic->cfqq[rw & REQ_RW_SYNC];
> if (cfqq) {
> cfq_init_prio_data(cfqq);
> cfq_prio_boost(cfqq);
Ahem, how well did you test this patch?
--
Jens Axboe
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| Re: [PATCH] cfq: get rid of cfqq hash [message #12322 is a reply to message #12320] |
Wed, 25 April 2007 07:51 |
Vasily Tarasov
Messages: 1345
Registered: January 2006
|
Senior Member |
|
|
>> @@ -1806,7 +1765,11 @@ static int cfq_may_queue(request_queue_t
>> * so just lookup a possibly existing queue, or return 'may queue'
>> * if that fails
>> */
>> - cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
>> + cic = cfq_get_io_context_noalloc(cfqd, tsk);
>> + if (!cic)
>> + return ELV_MQUEUE_MAY;
>> +
>> + cfqq = cic->cfqq[rw & REQ_RW_SYNC];
>> if (cfqq) {
>> cfq_init_prio_data(cfqq);
>> cfq_prio_boost(cfqq);
>
> Ahem, how well did you test this patch?
Ugh, again: bio_sync() returns not only 0/1
Sorry for giving so much trouble...
BTW, what tests do you use to check patches?
I'll run them on our nodes each time when sending it to you.
At the moment I use some self made tests and a bit fio scripts.
>
> --
> Jens Axboe
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| Re: [PATCH] cfq: get rid of cfqq hash [message #12323 is a reply to message #12322] |
Wed, 25 April 2007 07:57 |
Jens Axboe
Messages: 30
Registered: October 2006
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Member |
|
|
On Wed, Apr 25 2007, Vasily Tarasov wrote:
> >> @@ -1806,7 +1765,11 @@ static int cfq_may_queue(request_queue_t
> >> * so just lookup a possibly existing queue, or return 'may queue'
> >> * if that fails
> >> */
> >> - cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
> >> + cic = cfq_get_io_context_noalloc(cfqd, tsk);
> >> + if (!cic)
> >> + return ELV_MQUEUE_MAY;
> >> +
> >> + cfqq = cic->cfqq[rw & REQ_RW_SYNC];
> >> if (cfqq) {
> >> cfq_init_prio_data(cfqq);
> >> cfq_prio_boost(cfqq);
> >
> > Ahem, how well did you test this patch?
>
> Ugh, again: bio_sync() returns not only 0/1
> Sorry for giving so much trouble...
Right, and REQ_RW_SYNC isn't 1 either, so it returns a large number if
set.
> BTW, what tests do you use to check patches?
> I'll run them on our nodes each time when sending it to you.
> At the moment I use some self made tests and a bit fio scripts.
I went to run a test testing many disks, with a fio file like so:
[root@AS4 ~]# cat many-rw-256
[global]
rw=write
bs=256k
direct=1
ioengine=libaio
iodepth=4096
[md0]
file_service_type=roundrobin:16
filename=/dev/sdix:/dev/sdiw:/dev/sdiv:...
filename is 256 scsi disks, using scsi_debug. I wanted to evaluate the
possible extra CPU usage from one process with a lot of io contexts
attached. And the benefits of such a patch as this one:
http://git.kernel.dk/?p=linux-2.6-block.git ;a=commitdiff;h=7e950c8181e63345743130d839680999c5de968a;hp= 551e9405cb9e1f900da456ba57ddcf35dea110b9
--
Jens Axboe
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| Re: [PATCH] cfq: get rid of cfqq hash [message #12330 is a reply to message #12320] |
Wed, 25 April 2007 07:27 |
Jens Axboe
Messages: 30
Registered: October 2006
|
Member |
|
|
On Wed, Apr 25 2007, Jens Axboe wrote:
> On Tue, Apr 24 2007, Vasily Tarasov wrote:
> > @@ -1806,7 +1765,11 @@ static int cfq_may_queue(request_queue_t
> > * so just lookup a possibly existing queue, or return 'may queue'
> > * if that fails
> > */
> > - cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
> > + cic = cfq_get_io_context_noalloc(cfqd, tsk);
> > + if (!cic)
> > + return ELV_MQUEUE_MAY;
> > +
> > + cfqq = cic->cfqq[rw & REQ_RW_SYNC];
> > if (cfqq) {
> > cfq_init_prio_data(cfqq);
> > cfq_prio_boost(cfqq);
>
> Ahem, how well did you test this patch?
Incremental update to get things working below.
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index ed1ce43..17e4660 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -202,6 +202,18 @@ static struct cfq_queue *cfq_get_queue(struct cfq_data *, int,
static struct cfq_io_context *cfq_cic_rb_lookup(struct cfq_data *,
struct io_context *);
+static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
+ int is_sync)
+{
+ return cic->cfqq[!!is_sync];
+}
+
+static inline void cic_set_cfqq(struct cfq_io_context *cic,
+ struct cfq_queue *cfqq, int is_sync)
+{
+ cic->cfqq[!!is_sync] = cfqq;
+}
+
/*
* scheduler run of queue, if there are requests pending and no one in the
* driver that will restart queueing
@@ -582,7 +594,7 @@ cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
if (!cic)
return NULL;
- cfqq = cic->cfqq[bio_sync(bio)];
+ cfqq = cic_to_cfqq(cic, bio_sync(bio));
if (cfqq) {
sector_t sector = bio->bi_sector + bio_sectors(bio);
@@ -693,7 +705,7 @@ static int cfq_allow_merge(request_queue_t *q, struct request *rq,
if (!cic)
return 0;
- cfqq = cic->cfqq[bio_sync(bio)];
+ cfqq = cic_to_cfqq(cic, bio_sync(bio));
if (cfqq == RQ_CFQQ(rq))
return 1;
@@ -1330,7 +1342,7 @@ cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct task_struct *tsk,
retry:
cic = cfq_cic_rb_lookup(cfqd, tsk->io_context);
/* cic always exists here */
- cfqq = cic->cfqq[is_sync];
+ cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq) {
if (new_cfqq) {
@@ -1821,7 +1833,7 @@ static int cfq_may_queue(request_queue_t *q, int rw)
if (!cic)
return ELV_MQUEUE_MAY;
- cfqq = cic->cfqq[rw & REQ_RW_SYNC];
+ cfqq = cic_to_cfqq(cic, rw & REQ_RW_SYNC);
if (cfqq) {
cfq_init_prio_data(cfqq);
cfq_prio_boost(cfqq);
@@ -1877,15 +1889,15 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
if (!cic)
goto queue_fail;
- if (!cic->cfqq[is_sync]) {
+ cfqq = cic_to_cfqq(cic, is_sync);
+ if (!cfqq) {
cfqq = cfq_get_queue(cfqd, is_sync, tsk, gfp_mask);
if (!cfqq)
goto queue_fail;
- cic->cfqq[is_sync] = cfqq;
- } else
- cfqq = cic->cfqq[is_sync];
+ cic_set_cfqq(cic, cfqq, is_sync);
+ }
cfqq->allocated[rw]++;
cfq_clear_cfqq_must_alloc(cfqq);
--
Jens Axboe
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| Re: [PATCH] cfq: get rid of cfqq hash [message #12334 is a reply to message #12323] |
Wed, 25 April 2007 10:27 |
Jens Axboe
Messages: 30
Registered: October 2006
|
Member |
|
|
On Wed, Apr 25 2007, Jens Axboe wrote:
> On Wed, Apr 25 2007, Vasily Tarasov wrote:
> > >> @@ -1806,7 +1765,11 @@ static int cfq_may_queue(request_queue_t
> > >> * so just lookup a possibly existing queue, or return 'may queue'
> > >> * if that fails
> > >> */
> > >> - cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
> > >> + cic = cfq_get_io_context_noalloc(cfqd, tsk);
> > >> + if (!cic)
> > >> + return ELV_MQUEUE_MAY;
> > >> +
> > >> + cfqq = cic->cfqq[rw & REQ_RW_SYNC];
> > >> if (cfqq) {
> > >> cfq_init_prio_data(cfqq);
> > >> cfq_prio_boost(cfqq);
> > >
> > > Ahem, how well did you test this patch?
> >
> > Ugh, again: bio_sync() returns not only 0/1
> > Sorry for giving so much trouble...
>
> Right, and REQ_RW_SYNC isn't 1 either, so it returns a large number if
> set.
This is also needed, you can't just rely on bio_sync(), a check for a
READ is needed as well.
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 17e4660..b793817 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -215,6 +215,18 @@ static inline void cic_set_cfqq(struct cfq_io_context *cic,
}
/*
+ * We regard a request as SYNC, if it's either a read or has the SYNC bit
+ * set (in which case it could also be direct WRITE).
+ */
+static inline int cfq_bio_sync(struct bio *bio)
+{
+ if (bio_data_dir(bio) == READ || bio_sync(bio))
+ return 1;
+
+ return 0;
+}
+
+/*
* scheduler run of queue, if there are requests pending and no one in the
* driver that will restart queueing
*/
@@ -594,7 +606,7 @@ cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
if (!cic)
return NULL;
- cfqq = cic_to_cfqq(cic, bio_sync(bio));
+ cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
if (cfqq) {
sector_t sector = bio->bi_sector + bio_sectors(bio);
@@ -694,7 +706,7 @@ static int cfq_allow_merge(request_queue_t *q, struct request *rq,
/*
* Disallow merge of a sync bio into an async request.
*/
- if ((bio_data_dir(bio) == READ || bio_sync(bio)) && !rq_is_sync(rq))
+ if (cfq_bio_sync(bio) && !rq_is_sync(rq))
return 0;
/*
@@ -705,7 +717,7 @@ static int cfq_allow_merge(request_queue_t *q, struct request *rq,
if (!cic)
return 0;
- cfqq = cic_to_cfqq(cic, bio_sync(bio));
+ cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
if (cfqq == RQ_CFQQ(rq))
return 1;
--
Jens Axboe
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