From: Johannes Weiner <hannes@cmpxchg.org>
To: Michal Hocko <mhocko@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Glauber Costa <glommer@parallels.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
Li Zefan <lizefan@huawei.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Balbir Singh <bsingharora@gmail.com>
Subject: Re: [PATCH v3 3/6] memcg: Simplify mem_cgroup_force_empty_list error handling
Date: Wed, 14 Nov 2012 13:33:30 -0500 [thread overview]
Message-ID: <20121114183330.GA32421@cmpxchg.org> (raw)
In-Reply-To: <20121114135930.GE4929@dhcp22.suse.cz>
On Wed, Nov 14, 2012 at 02:59:30PM +0100, Michal Hocko wrote:
> On Tue 13-11-12 16:10:41, Johannes Weiner wrote:
> > Would it make sense to stick a wait_on_page_locked() in there just so
> > that we don't busy spin on a page under migration/reclaim?
>
> Hmm, this would also mean that get_page_unless_zero would fail as well
> and so we would schedule in mem_cgroup_force_empty_list. It is true that
> there might be no other runnable task so we can busy loop so yes this
> would help. Care to cook the patch?
Eventually get_page_unless_zero() would fail but we could still spin
on a page while it's off the LRU and migration performs writeback on
it e.g. cond_resched() does not necessarily schedule just because
there is another runnable task, I think, it's voluntary preemption
when the task needs rescheduling anyway, not yield.
Maybe not worth bothering...
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WARNING: multiple messages have this Message-ID (diff)
From: Johannes Weiner <hannes@cmpxchg.org>
To: Michal Hocko <mhocko@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Glauber Costa <glommer@parallels.com>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
Li Zefan <lizefan@huawei.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Balbir Singh <bsingharora@gmail.com>
Subject: Re: [PATCH v3 3/6] memcg: Simplify mem_cgroup_force_empty_list error handling
Date: Wed, 14 Nov 2012 13:33:30 -0500 [thread overview]
Message-ID: <20121114183330.GA32421@cmpxchg.org> (raw)
In-Reply-To: <20121114135930.GE4929@dhcp22.suse.cz>
On Wed, Nov 14, 2012 at 02:59:30PM +0100, Michal Hocko wrote:
> On Tue 13-11-12 16:10:41, Johannes Weiner wrote:
> > Would it make sense to stick a wait_on_page_locked() in there just so
> > that we don't busy spin on a page under migration/reclaim?
>
> Hmm, this would also mean that get_page_unless_zero would fail as well
> and so we would schedule in mem_cgroup_force_empty_list. It is true that
> there might be no other runnable task so we can busy loop so yes this
> would help. Care to cook the patch?
Eventually get_page_unless_zero() would fail but we could still spin
on a page while it's off the LRU and migration performs writeback on
it e.g. cond_resched() does not necessarily schedule just because
there is another runnable task, I think, it's voluntary preemption
when the task needs rescheduling anyway, not yield.
Maybe not worth bothering...
next prev parent reply other threads:[~2012-11-14 18:33 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-26 11:37 memcg/cgroup: do not fail fail on pre_destroy callbacks Michal Hocko
2012-10-26 11:37 ` Michal Hocko
2012-10-26 11:37 ` Michal Hocko
2012-10-26 11:37 ` [PATCH v3 1/6] memcg: split mem_cgroup_force_empty into reclaiming and reparenting parts Michal Hocko
2012-10-26 11:37 ` Michal Hocko
2012-10-29 13:45 ` Glauber Costa
2012-10-29 13:45 ` Glauber Costa
[not found] ` <1351251453-6140-2-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org>
2012-10-31 16:29 ` Johannes Weiner
2012-10-31 16:29 ` Johannes Weiner
2012-10-31 16:29 ` Johannes Weiner
2012-10-26 11:37 ` [PATCH v3 2/6] memcg: root_cgroup cannot reach mem_cgroup_move_parent Michal Hocko
2012-10-26 11:37 ` Michal Hocko
2012-10-29 13:48 ` Glauber Costa
2012-10-29 13:48 ` Glauber Costa
[not found] ` <508E8910.40203-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-29 13:52 ` Michal Hocko
2012-10-29 13:52 ` Michal Hocko
2012-10-29 13:52 ` Michal Hocko
[not found] ` <1351251453-6140-3-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org>
2012-10-31 16:31 ` Johannes Weiner
2012-10-31 16:31 ` Johannes Weiner
2012-10-31 16:31 ` Johannes Weiner
2012-10-26 11:37 ` [PATCH v3 3/6] memcg: Simplify mem_cgroup_force_empty_list error handling Michal Hocko
2012-10-26 11:37 ` Michal Hocko
[not found] ` <1351251453-6140-4-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org>
2012-10-29 13:58 ` Glauber Costa
2012-10-29 13:58 ` Glauber Costa
2012-10-29 13:58 ` Glauber Costa
[not found] ` <508E8B95.406-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-29 14:15 ` Michal Hocko
2012-10-29 14:15 ` Michal Hocko
2012-10-29 14:15 ` Michal Hocko
2012-10-29 15:09 ` Glauber Costa
2012-10-29 15:09 ` Glauber Costa
2012-10-29 22:00 ` Andrew Morton
2012-10-29 22:00 ` Andrew Morton
[not found] ` <20121029150022.a595b866.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2012-10-30 10:35 ` Michal Hocko
2012-10-30 10:35 ` Michal Hocko
2012-10-30 10:35 ` Michal Hocko
[not found] ` <20121030103559.GA7394-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-31 21:30 ` Andrew Morton
2012-10-31 21:30 ` Andrew Morton
2012-10-31 21:30 ` Andrew Morton
2012-11-13 21:10 ` Johannes Weiner
2012-11-13 21:10 ` Johannes Weiner
[not found] ` <20121113211041.GB1543-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2012-11-14 13:59 ` Michal Hocko
2012-11-14 13:59 ` Michal Hocko
2012-11-14 13:59 ` Michal Hocko
2012-11-14 18:33 ` Johannes Weiner [this message]
2012-11-14 18:33 ` Johannes Weiner
2012-10-26 11:37 ` [PATCH v3 4/6] cgroups: forbid pre_destroy callback to fail Michal Hocko
2012-10-26 11:37 ` Michal Hocko
[not found] ` <1351251453-6140-5-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org>
2012-10-29 14:04 ` Glauber Costa
2012-10-29 14:04 ` Glauber Costa
2012-10-29 14:04 ` Glauber Costa
[not found] ` <508E8CDE.1090702-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-29 14:06 ` Glauber Costa
2012-10-29 14:06 ` Glauber Costa
2012-10-29 14:06 ` Glauber Costa
[not found] ` <508E8D6A.5040602-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-29 14:17 ` Michal Hocko
2012-10-29 14:17 ` Michal Hocko
2012-10-29 14:17 ` Michal Hocko
2012-11-13 21:13 ` Johannes Weiner
2012-11-13 21:13 ` Johannes Weiner
2012-10-26 11:37 ` [PATCH v3 5/6] memcg: make mem_cgroup_reparent_charges non failing Michal Hocko
2012-10-26 11:37 ` Michal Hocko
2012-10-29 14:07 ` Glauber Costa
2012-10-29 14:07 ` Glauber Costa
2012-10-26 11:37 ` [PATCH v3 6/6] hugetlb: do not fail in hugetlb_cgroup_pre_destroy Michal Hocko
2012-10-26 11:37 ` Michal Hocko
2012-10-29 14:08 ` Glauber Costa
2012-10-29 14:08 ` Glauber Costa
2012-10-29 23:26 ` memcg/cgroup: do not fail fail on pre_destroy callbacks Tejun Heo
2012-10-29 23:26 ` Tejun Heo
[not found] ` <20121029232602.GF4066-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-30 23:37 ` Michal Hocko
2012-10-30 23:37 ` Michal Hocko
2012-10-30 23:37 ` Michal Hocko
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