From: Tejun Heo <tj@kernel.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
axboe@kernel.dk, hughd@google.com, avi@redhat.com,
nate@cpanel.net, cl@linux-foundation.org,
linux-kernel@vger.kernel.org, dpshah@google.com,
ctalbott@google.com, rni@google.com
Subject: Re: [PATCHSET] mempool, percpu, blkcg: fix percpu stat allocation and remove stats_lock
Date: Thu, 8 Mar 2012 12:35:35 -0800 [thread overview]
Message-ID: <20120308203535.GE25508@google.com> (raw)
In-Reply-To: <20120308203331.GE22922@redhat.com>
Hello, Vivek.
On Thu, Mar 08, 2012 at 03:33:31PM -0500, Vivek Goyal wrote:
> Ok, I can confirm that it is cfqq reference on blkg which is an issue. If
> I move my shell to a child cgroup and try to do some operations (in the
> context of shell, like autocompletion/reading an uncached dir), then IO
> is issued in the context of shell, I move out the shell out of cgroup and
> then try to delete it, it hangs. Once I exit out of shell, blkg reference
> is dropped and cgroup is deleted.
>
> So we do need to cleanup the cic->cfqq upon cgroup change synchronously.
I see. Thanks for confirming the problem.
> That will still not solve the issue of a process dumping tons of
> IO on device (large nr_requests) and then moving out of cgroup. Now
> cgroup deletion will still hang till all the IO in the cgroup
> completes.
I don't think the latter is too much of a problem. I've been meaning
to decouple destruction from ref putting anyway, so let's see whether
that's possible.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-03-08 20:35 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-23 22:30 [PATCHSET] mempool, percpu, blkcg: fix percpu stat allocation and remove stats_lock Tejun Heo
2012-02-23 22:30 ` [PATCH 1/8] mempool: factor out mempool_fill() Tejun Heo
2012-02-23 22:30 ` [PATCH 2/8] mempool: separate out __mempool_create() Tejun Heo
2012-02-23 22:30 ` [PATCH 3/8] mempool, percpu: implement percpu mempool Tejun Heo
2012-02-23 22:30 ` [PATCH 4/8] block: fix deadlock through percpu allocation in blk-cgroup Tejun Heo
2012-02-23 22:30 ` [PATCH 5/8] blkcg: don't use percpu for merged stats Tejun Heo
2012-02-23 22:30 ` [PATCH 6/8] blkcg: simplify stat reset Tejun Heo
2012-02-23 22:30 ` [PATCH 7/8] blkcg: restructure blkio_get_stat() Tejun Heo
2012-02-23 22:30 ` [PATCH 8/8] blkcg: remove blkio_group->stats_lock Tejun Heo
2012-02-23 22:43 ` [PATCHSET] mempool, percpu, blkcg: fix percpu stat allocation and remove stats_lock Andrew Morton
2012-02-23 23:01 ` Tejun Heo
2012-02-23 23:12 ` Tejun Heo
2012-02-23 23:22 ` Andrew Morton
2012-02-23 23:24 ` Tejun Heo
2012-02-24 14:20 ` Vivek Goyal
2012-02-25 21:44 ` Tejun Heo
2012-02-27 3:11 ` Vivek Goyal
2012-02-27 9:11 ` Tejun Heo
2012-02-27 19:43 ` Vivek Goyal
2012-02-29 17:36 ` Vivek Goyal
2012-03-05 22:13 ` Tejun Heo
2012-03-06 21:09 ` Vivek Goyal
2012-03-06 21:20 ` Andrew Morton
2012-03-06 21:34 ` Vivek Goyal
2012-03-06 21:55 ` Andrew Morton
2012-03-07 14:55 ` Vivek Goyal
2012-03-07 17:05 ` Tejun Heo
2012-03-07 19:13 ` Vivek Goyal
2012-03-07 19:22 ` Tejun Heo
2012-03-07 19:42 ` Vivek Goyal
2012-03-07 22:56 ` Tejun Heo
2012-03-07 23:08 ` Andrew Morton
2012-03-07 23:15 ` Tejun Heo
2012-03-07 23:05 ` Andrew Morton
2012-03-08 17:57 ` Vivek Goyal
2012-03-08 18:08 ` Tejun Heo
2012-03-08 18:11 ` Tejun Heo
2012-03-08 18:22 ` Vivek Goyal
2012-03-08 18:27 ` Tejun Heo
2012-03-15 16:48 ` Vivek Goyal
2012-03-15 16:59 ` Tejun Heo
2012-03-20 11:50 ` Jens Axboe
2012-03-08 20:16 ` Vivek Goyal
2012-03-08 20:33 ` Vivek Goyal
2012-03-08 20:35 ` Tejun Heo [this message]
2012-03-08 19:06 ` Andrew Morton
2012-02-25 3:44 ` Vivek Goyal
2012-02-25 21:46 ` Tejun Heo
2012-02-25 22:21 ` Tejun Heo
2012-02-27 14:25 ` Vivek Goyal
2012-02-27 14:40 ` Vivek Goyal
2012-03-05 17:45 ` Tejun Heo
2012-02-27 18:22 ` Vivek Goyal
2012-02-29 19:03 ` Vivek Goyal
2012-03-05 17:20 ` Tejun Heo
2012-03-05 18:03 ` Vivek Goyal
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