From: Tejun Heo <tj@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Shaohua Li <shaohua.li@intel.com>, Jens Axboe <axboe@kernel.dk>,
Vivek Goyal <vgoyal@redhat.com>,
lkml <linux-kernel@vger.kernel.org>,
Knut Petersen <Knut_Petersen@t-online.de>,
mroos@linux.ee
Subject: Re: [PATCH] block: strip out locking optimization in put_io_context()
Date: Wed, 8 Feb 2012 09:23:13 -0800 [thread overview]
Message-ID: <20120208172313.GD19392@google.com> (raw)
In-Reply-To: <20120208165611.GC19392@google.com>
On Wed, Feb 08, 2012 at 08:56:11AM -0800, Tejun Heo wrote:
> On Wed, Feb 08, 2012 at 08:49:20AM -0800, Tejun Heo wrote:
> > I'm still a bit lost on where the regression is coming from and
> > *suspecting* that queue_lock contention is making the reverse locking
> > behave much worse than expected, so I mostly wanted to take that out
> > and see what happens.
>
> IOW, we can achieve about the same thing by adding another lock in
> request_queue. The goal is using an inner lock for ioc clearing so
> that queue_lock doesn't have to be grabbed inside ioc lock.
Urgh....... forget about the above message. My head is still booting.
We can't do this w/ per-queue lock as we don't have a way to traverse
the associated queues w/o holding the lock and we need read locking on
ioc exit path as we may recurse through elevator icq exit (it's not
about concurrency). /me goes to brew coffee.
--
tejun
next prev parent reply other threads:[~2012-02-08 17:23 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-06 7:50 [patch]block: fix ioc locking warning Shaohua Li
2012-02-06 7:55 ` Jens Axboe
2012-02-06 15:12 ` Vivek Goyal
2012-02-06 16:09 ` Jens Axboe
2012-02-06 16:37 ` Vivek Goyal
2012-02-06 16:44 ` Tejun Heo
2012-02-06 16:58 ` Linus Torvalds
2012-02-06 17:27 ` Tejun Heo
2012-02-06 20:16 ` Jens Axboe
2012-02-06 21:54 ` [PATCH] block: strip out locking optimization in put_io_context() Tejun Heo
2012-02-07 6:49 ` Jens Axboe
2012-02-07 16:22 ` Tejun Heo
2012-02-07 16:28 ` Jens Axboe
2012-02-07 16:33 ` Linus Torvalds
2012-02-07 16:47 ` Tejun Heo
2012-02-07 17:17 ` Tejun Heo
2012-02-08 0:19 ` Shaohua Li
2012-02-08 8:29 ` Shaohua Li
2012-02-08 16:29 ` Tejun Heo
2012-02-08 16:34 ` Linus Torvalds
2012-02-08 16:49 ` Tejun Heo
2012-02-08 16:56 ` Tejun Heo
2012-02-08 17:23 ` Tejun Heo [this message]
2012-02-09 6:22 ` Shaohua Li
2012-02-09 17:59 ` Tejun Heo
2012-02-09 18:07 ` Linus Torvalds
2012-02-09 19:24 ` Tejun Heo
2012-02-09 23:48 ` Tejun Heo
2012-02-10 5:14 ` Shaohua Li
2012-02-10 8:48 ` Shaohua Li
2012-02-11 2:17 ` Tejun Heo
2012-02-11 11:35 ` Jens Axboe
2012-02-13 1:34 ` Shaohua Li
2012-02-13 20:49 ` Tejun Heo
2012-02-14 2:36 ` Shaohua Li
2012-02-14 16:39 ` Tejun Heo
2012-02-10 3:09 ` Shaohua Li
2012-02-07 23:00 ` [PATCH] block: fix lockdep warning on io_context release put_io_context() Tejun Heo
2012-02-06 20:36 ` [patch]block: fix ioc locking warning Tejun Heo
2012-02-07 0:31 ` Shaohua Li
2012-02-07 0:39 ` Tejun Heo
2012-02-07 0:43 ` Shaohua Li
2012-02-07 0:59 ` Tejun Heo
2012-02-07 1:10 ` Shaohua Li
2012-02-07 1:33 ` Shaohua Li
2012-02-07 5:22 ` Shaohua Li
2012-02-07 22:34 ` Linus Torvalds
2012-02-06 16:22 ` Tejun Heo
2012-02-08 18:07 ` walt
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