From: Johannes Weiner <hannes@cmpxchg.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Rik van Riel <riel@redhat.com>, Hugh Dickins <hugh@veritas.com>
Subject: Re: [patch 3/3][rfc] vmscan: batched swap slot allocation
Date: Tue, 21 Apr 2009 11:38:30 +0200 [thread overview]
Message-ID: <20090421093830.GA3639@cmpxchg.org> (raw)
In-Reply-To: <20090421182427.F14D.A69D9226@jp.fujitsu.com>
On Tue, Apr 21, 2009 at 06:27:08PM +0900, KOSAKI Motohiro wrote:
> > > > - cond_resched();
> > > > + if (list_empty(&swap_pages))
> > > > + cond_resched();
> > > >
> > > Why this ?
> >
> > It shouldn't schedule anymore when it's allocated the first swap slot.
> > Another reclaimer could e.g. sleep on the cond_resched() before the
> > loop and when we schedule while having swap slots allocated, we might
> > continue further allocations multiple slots ahead.
>
> Oops, It seems regression. this cond_resched() intent to
>
> cond_resched();
> pageout();
> cond_resched();
> pageout();
> cond_resched();
> pageout();
It still does that. While it collects swap pages (swap_pages list is
non-empty), it doesn't page out. And if it restarts for unmap and
page-out, the swap_pages list is empty and cond_resched() is called.
WARNING: multiple messages have this Message-ID (diff)
From: Johannes Weiner <hannes@cmpxchg.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Rik van Riel <riel@redhat.com>, Hugh Dickins <hugh@veritas.com>
Subject: Re: [patch 3/3][rfc] vmscan: batched swap slot allocation
Date: Tue, 21 Apr 2009 11:38:30 +0200 [thread overview]
Message-ID: <20090421093830.GA3639@cmpxchg.org> (raw)
In-Reply-To: <20090421182427.F14D.A69D9226@jp.fujitsu.com>
On Tue, Apr 21, 2009 at 06:27:08PM +0900, KOSAKI Motohiro wrote:
> > > > - cond_resched();
> > > > + if (list_empty(&swap_pages))
> > > > + cond_resched();
> > > >
> > > Why this ?
> >
> > It shouldn't schedule anymore when it's allocated the first swap slot.
> > Another reclaimer could e.g. sleep on the cond_resched() before the
> > loop and when we schedule while having swap slots allocated, we might
> > continue further allocations multiple slots ahead.
>
> Oops, It seems regression. this cond_resched() intent to
>
> cond_resched();
> pageout();
> cond_resched();
> pageout();
> cond_resched();
> pageout();
It still does that. While it collects swap pages (swap_pages list is
non-empty), it doesn't page out. And if it restarts for unmap and
page-out, the swap_pages list is empty and cond_resched() is called.
--
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next prev parent reply other threads:[~2009-04-21 9:40 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-20 20:24 [patch 1/3] mm: fix pageref leak in do_swap_page() Johannes Weiner
2009-04-20 20:24 ` Johannes Weiner
2009-04-20 20:24 ` [patch 2/3][rfc] swap: try to reuse freed slots in the allocation area Johannes Weiner
2009-04-20 20:24 ` Johannes Weiner
2009-04-22 19:59 ` Hugh Dickins
2009-04-22 19:59 ` Hugh Dickins
2009-04-27 8:02 ` Johannes Weiner
2009-04-27 8:02 ` Johannes Weiner
2009-04-20 20:24 ` [patch 3/3][rfc] vmscan: batched swap slot allocation Johannes Weiner
2009-04-20 20:24 ` Johannes Weiner
2009-04-20 20:31 ` Johannes Weiner
2009-04-20 20:53 ` Andrew Morton
2009-04-20 20:53 ` Andrew Morton
2009-04-20 21:38 ` Johannes Weiner
2009-04-20 21:38 ` Johannes Weiner
2009-04-21 0:58 ` KAMEZAWA Hiroyuki
2009-04-21 0:58 ` KAMEZAWA Hiroyuki
2009-04-21 8:52 ` Johannes Weiner
2009-04-21 8:52 ` Johannes Weiner
2009-04-21 9:23 ` KAMEZAWA Hiroyuki
2009-04-21 9:23 ` KAMEZAWA Hiroyuki
2009-04-21 9:54 ` Johannes Weiner
2009-04-21 9:54 ` Johannes Weiner
2009-04-21 9:27 ` KOSAKI Motohiro
2009-04-21 9:27 ` KOSAKI Motohiro
2009-04-21 9:38 ` Johannes Weiner [this message]
2009-04-21 9:38 ` Johannes Weiner
2009-04-21 9:41 ` KOSAKI Motohiro
2009-04-21 9:41 ` KOSAKI Motohiro
2009-04-22 20:37 ` Hugh Dickins
2009-04-22 20:37 ` Hugh Dickins
2009-04-27 7:46 ` Johannes Weiner
2009-04-27 7:46 ` Johannes Weiner
2009-04-20 23:36 ` [patch 1/3] mm: fix pageref leak in do_swap_page() Minchan Kim
2009-04-20 23:36 ` Minchan Kim
2009-04-21 3:14 ` Balbir Singh
2009-04-21 3:14 ` Balbir Singh
2009-04-21 8:19 ` Johannes Weiner
2009-04-21 8:19 ` Johannes Weiner
2009-04-21 8:45 ` Balbir Singh
2009-04-21 8:45 ` Balbir Singh
2009-04-21 3:44 ` KAMEZAWA Hiroyuki
2009-04-21 3:44 ` KAMEZAWA Hiroyuki
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