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authorTejun Heo <tj@kernel.org>2012-02-07 07:51:30 +0100
committerJens Axboe <axboe@kernel.dk>2012-02-07 07:51:30 +0100
commit11a3122f6cf2d988a77eb8883d0fc49cd013a6d5 (patch)
treeded8ea8a2982754ff0c58448a7ed2e59487104cb /block/blk-cgroup.c
parent822bfa51ce44f2c63c300fdb76dc99c4d5a5ca9f (diff)
downloadlinux-linaro-stable-11a3122f6cf2d988a77eb8883d0fc49cd013a6d5.tar.gz
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.c2
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);
}
}
}