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authorJens Axboe <axboe@suse.de>2006-06-13 08:26:10 +0200
committerJens Axboe <axboe@nelson.home.kernel.dk>2006-06-23 17:10:39 +0200
commitb31dc66a54ad986b6b73bdc49c8efc17cbad1833 (patch)
tree5591383c1cbffe11512da889c971f899333f1a44 /block
parent271f18f102c789f59644bb6c53a69da1df72b2f4 (diff)
downloadlinux-linaro-stable-b31dc66a54ad986b6b73bdc49c8efc17cbad1833.tar.gz
[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')
-rw-r--r--block/as-iosched.c2
-rw-r--r--block/cfq-iosched.c4
-rw-r--r--block/ll_rw_blk.c3
3 files changed, 5 insertions, 4 deletions
diff --git a/block/as-iosched.c b/block/as-iosched.c
index 9b13d72ffefa..56c99fa037df 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -1339,7 +1339,7 @@ static void as_add_request(request_queue_t *q, struct request *rq)
arq->state = AS_RQ_NEW;
if (rq_data_dir(arq->request) == READ
- || current->flags&PF_SYNCWRITE)
+ || (arq->request->flags & REQ_RW_SYNC))
arq->is_sync = 1;
else
arq->is_sync = 0;
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;
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 17c42ddd31db..2270bb451385 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -2827,6 +2827,9 @@ static void init_request_from_bio(struct request *req, struct bio *bio)
if (unlikely(bio_barrier(bio)))
req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
+ if (bio_sync(bio))
+ req->flags |= REQ_RW_SYNC;
+
req->errors = 0;
req->hard_sector = req->sector = bio->bi_sector;
req->hard_nr_sectors = req->nr_sectors = bio_sectors(bio);