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| author | Shaohua Li <shaohua.li@intel.com> | 2011-08-24 16:04:32 +0200 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2011-08-24 16:04:32 +0200 |
| commit | a63271627521b825b0dd0a564e9a9c62b4c1ca89 (patch) | |
| tree | 8cb0076737679544da5de89484548c921e2131cc /block | |
| parent | e8037d49835482c9534a9a07bed0d0ea831135ae (diff) | |
| download | linux-a63271627521b825b0dd0a564e9a9c62b4c1ca89.tar.gz | |
block: change force plug flush call order
Do blk_flush_plug_list() first and then add new request aDo blk_flush_plug_list() first and then add new request aDo blk_flush_plug_list() first and then add new request at the tail. New request can't be merged to existing requests, but later new requests might be merged with this new one. If blk_flush_plug_list() is done later, the merge doesn't happen. Believe it or not, this fixes a 10% regression running sysbench workload. Signed-off-by: Shaohua Li <shli@kernel.org> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-core.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 90e1ffdeb415..67dba6941194 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1302,11 +1302,11 @@ get_rq: if (__rq->q != q) plug->should_sort = 1; } - list_add_tail(&req->queuelist, &plug->list); - plug->count++; - drive_stat_acct(req, 1); if (plug->count >= BLK_MAX_REQUEST_COUNT) blk_flush_plug_list(plug, false); + plug->count++; + list_add_tail(&req->queuelist, &plug->list); + drive_stat_acct(req, 1); } else { spin_lock_irq(q->queue_lock); add_acct_request(q, req, where); |