From: Andrew Morton <akpm@linux-foundation.org>
To: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <clameter@sgi.com>,
Andrea Arcangeli <andrea@suse.de>, Rik van Riel <riel@redhat.com>,
linux-mm@kvack.org
Subject: Re: [patch 4/9] oom: add per-zone locking
Date: Fri, 21 Sep 2007 01:59:24 -0700 [thread overview]
Message-ID: <20070921015924.62959c24.akpm@linux-foundation.org> (raw)
In-Reply-To: <alpine.DEB.0.9999.0709201538310.2658@chino.kir.corp.google.com>
On Thu, 20 Sep 2007 15:48:36 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:
> > The global lock there just spooks me. If a large number of processors get
> > in there (say 1000 or so in the case of a global oom) then there is
> > already an issue of getting the lock from node 0. The bits in the zone
> > are distributed over all of the nodes in the system.
> >
>
> It's no more harder to acquire than callback_mutex was. It's far better
> to include this global lock so the state of the zones are always correct
> after releasing it than to have 1000 processors clearing and setting
> ZONE_OOM_LOCKED bits for lengthy zonelists and all racing with each other
> so no zonelist is ever fully locked.
It'd be better to use a spinlock than a sleeping lock: same speed in the
uncontended case, heaps faster in the contended case.
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next prev parent reply other threads:[~2007-09-21 8:59 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-20 20:23 [patch 0/9] oom killer serialization David Rientjes
2007-09-20 20:23 ` [patch 1/9] oom: move prototypes to appropriate header file David Rientjes
2007-09-20 20:23 ` [patch 2/9] oom: move constraints to enum David Rientjes
2007-09-20 20:23 ` [patch 3/9] oom: change all_unreclaimable zone member to flags David Rientjes
2007-09-20 20:23 ` [patch 4/9] oom: add per-zone locking David Rientjes
2007-09-20 20:23 ` [patch 5/9] oom: serialize out of memory calls David Rientjes
2007-09-20 20:23 ` [patch 6/9] oom: add oom_kill_asking_task sysctl David Rientjes
2007-09-20 20:23 ` [patch 7/9] oom: suppress extraneous stack and memory dump David Rientjes
2007-09-20 20:23 ` [patch 8/9] oom: compare cpuset mems_allowed instead of exclusive ancestors David Rientjes
2007-09-20 20:23 ` [patch 9/9] oom: do not take callback_mutex David Rientjes
2007-09-20 22:04 ` Christoph Lameter
2007-09-20 22:01 ` [patch 8/9] oom: compare cpuset mems_allowed instead of exclusive ancestors Christoph Lameter
2007-09-20 22:00 ` [patch 7/9] oom: suppress extraneous stack and memory dump Christoph Lameter
2007-09-20 22:03 ` [patch 6/9] oom: add oom_kill_asking_task sysctl Christoph Lameter
2007-09-20 22:07 ` David Rientjes
2007-09-20 22:09 ` Christoph Lameter
2007-09-21 9:05 ` Andrew Morton
2007-09-20 21:59 ` [patch 5/9] oom: serialize out of memory calls Christoph Lameter
2007-09-21 9:01 ` Andrew Morton
2007-09-21 20:04 ` David Rientjes
2007-09-20 21:59 ` [patch 4/9] oom: add per-zone locking Christoph Lameter
2007-09-20 22:03 ` David Rientjes
2007-09-20 22:05 ` Christoph Lameter
2007-09-20 22:12 ` David Rientjes
2007-09-20 22:26 ` Christoph Lameter
2007-09-20 22:48 ` David Rientjes
2007-09-21 8:59 ` Andrew Morton [this message]
2007-09-20 21:56 ` [patch 3/9] oom: change all_unreclaimable zone member to flags Christoph Lameter
2007-09-20 21:58 ` David Rientjes
2007-09-21 8:55 ` Andrew Morton
2007-09-21 9:12 ` [patch 0/9] oom killer serialization Andrew Morton
2007-09-21 9:21 ` David Rientjes
2007-09-21 19:13 ` David Rientjes
2007-09-21 19:15 ` Christoph Lameter
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