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| author | Jens Axboe <axboe@suse.de> | 2006-06-13 08:26:10 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@nelson.home.kernel.dk> | 2006-06-23 17:10:39 +0200 |
| commit | b31dc66a54ad986b6b73bdc49c8efc17cbad1833 (patch) | |
| tree | 5591383c1cbffe11512da889c971f899333f1a44 /block/cfq-iosched.c | |
| parent | 271f18f102c789f59644bb6c53a69da1df72b2f4 (diff) | |
| download | lwn-b31dc66a54ad986b6b73bdc49c8efc17cbad1833.tar.gz lwn-b31dc66a54ad986b6b73bdc49c8efc17cbad1833.zip | |
[PATCH] Kill PF_SYNCWRITE flag
A process flag to indicate whether we are doing sync io is incredibly
ugly. It also causes performance problems when one does a lot of async
io and then proceeds to sync it. Part of the io will go out as async,
and the other part as sync. This causes a disconnect between the
previously submitted io and the synced io. For io schedulers such as CFQ,
this will cause us lost merges and suboptimal behaviour in scheduling.
Remove PF_SYNCWRITE completely from the fsync/msync paths, and let
the O_DIRECT path just directly indicate that the writes are sync
by using WRITE_SYNC instead.
Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'block/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index c88f161d3fb3..4c4e9cc3ae26 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -277,8 +277,6 @@ static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsi static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); -#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) - /* * lots of deadline iosched dupes, can be abstracted later... */ @@ -334,7 +332,7 @@ static int cfq_queue_empty(request_queue_t *q) static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) { - if (rw == READ || process_sync(task)) + if (rw == READ || rw == WRITE_SYNC) return task->pid; return CFQ_KEY_ASYNC; |