From: Rik van Riel <riel@redhat.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
David Rientjes <rientjes@google.com>
Subject: Re: [for -mm][PATCH][1/2] page reclaim throttle take3
Date: Sat, 22 Mar 2008 10:55:31 -0400 [thread overview]
Message-ID: <20080322105531.23f2bfdf@bree.surriel.com> (raw)
In-Reply-To: <20080322192928.B30B.KOSAKI.MOTOHIRO@jp.fujitsu.com>
On Sat, 22 Mar 2008 19:45:54 +0900
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
> + wait_event(zone->reclaim_throttle_waitq,
> + atomic_add_unless(&zone->nr_reclaimers, 1,
> + CONFIG_NR_MAX_RECLAIM_TASKS_PER_ZONE));
I like your patch, but can see one potential problem. Sometimes
tasks that go into page reclaim with GFP_HIGHUSER end up recursing
back into page reclaim without __GFP_FS and/or __GFP_IO.
In that scenario, a task could end up waiting on itself and
deadlocking.
Maybe we should only let tasks with __GFP_FS, __GFP_IO and other
"I can do everything" flags wait on this waitqueue, letting the
tasks that cannot do IO (and are just here to reclaim clean pages)
bypass this waitqueue.
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next prev parent reply other threads:[~2008-03-22 14:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-22 10:45 KOSAKI Motohiro
2008-03-22 10:51 ` [for -mm][PATCH][2/2] " KOSAKI Motohiro
2008-03-22 14:55 ` Rik van Riel [this message]
2008-03-22 16:01 ` [for -mm][PATCH][1/2] " KOSAKI Motohiro
2008-03-22 16:15 ` Rik van Riel
2008-03-22 16:43 ` KOSAKI Motohiro
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