diff options
| author | Tejun Heo <tj@kernel.org> | 2012-02-07 07:51:30 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2012-02-07 07:51:30 +0100 |
| commit | 11a3122f6cf2d988a77eb8883d0fc49cd013a6d5 (patch) | |
| tree | ded8ea8a2982754ff0c58448a7ed2e59487104cb /block/blk-core.c | |
| parent | 822bfa51ce44f2c63c300fdb76dc99c4d5a5ca9f (diff) | |
| download | blackbird-op-linux-11a3122f6cf2d988a77eb8883d0fc49cd013a6d5.tar.gz blackbird-op-linux-11a3122f6cf2d988a77eb8883d0fc49cd013a6d5.zip | |
block: strip out locking optimization in put_io_context()
put_io_context() performed a complex trylock dancing to avoid
deferring ioc release to workqueue. It was also broken on UP because
trylock was always assumed to succeed which resulted in unbalanced
preemption count.
While there are ways to fix the UP breakage, even the most
pathological microbench (forced ioc allocation and tight fork/exit
loop) fails to show any appreciable performance benefit of the
optimization. Strip it out. If there turns out to be workloads which
are affected by this change, simpler optimization from the discussion
thread can be applied later.
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <1328514611.21268.66.camel@sli10-conroe>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-core.c')
| -rw-r--r-- | block/blk-core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 636702575118..532b3a21b383 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -642,7 +642,7 @@ static inline void blk_free_request(struct request_queue *q, struct request *rq) if (rq->cmd_flags & REQ_ELVPRIV) { elv_put_request(q, rq); if (rq->elv.icq) - put_io_context(rq->elv.icq->ioc, q); + put_io_context(rq->elv.icq->ioc); } mempool_free(rq, q->rq.rq_pool); |
