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-cgroup.c | |
| parent | cdrom: use copy_to_user() without the underscores (diff) | |
| download | linux-dev-11a3122f6cf2d988a77eb8883d0fc49cd013a6d5.tar.xz linux-dev-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-cgroup.c')
| -rw-r--r-- | block/blk-cgroup.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index fa8f26309444..75642a352a8f 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1659,7 +1659,7 @@ static void blkiocg_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE); if (ioc) { ioc_cgroup_changed(ioc); - put_io_context(ioc, NULL); + put_io_context(ioc); } } } |