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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 /kernel
parent822bfa51ce44f2c63c300fdb76dc99c4d5a5ca9f (diff)
downloadop-kernel-dev-11a3122f6cf2d988a77eb8883d0fc49cd013a6d5.zip
op-kernel-dev-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 'kernel')
-rw-r--r--kernel/fork.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 051f090..c574aef 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -890,7 +890,7 @@ static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
return -ENOMEM;
new_ioc->ioprio = ioc->ioprio;
- put_io_context(new_ioc, NULL);
+ put_io_context(new_ioc);
}
#endif
return 0;
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