From: Ying Han <yinghan@google.com>
To: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Michal Hocko <mhocko@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>, Mel Gorman <mel@csn.ul.ie>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Minchan Kim <minchan.kim@gmail.com>,
Hugh Dickins <hughd@google.com>, Nick Piggin <npiggin@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org
Subject: Re: [RFC PATCH] do_try_to_free_pages() might enter infinite loop
Date: Tue, 24 Apr 2012 10:17:40 -0700 [thread overview]
Message-ID: <CALWz4iynFr02wzpB5k7nJasGAmHVEOtp56Lo7m4bRHoNgDEkvQ@mail.gmail.com> (raw)
In-Reply-To: <4F96D6EE.6000809@redhat.com>
On Tue, Apr 24, 2012 at 9:38 AM, Rik van Riel <riel@redhat.com> wrote:
> On 04/24/2012 12:36 PM, Ying Han wrote:
>
>> However, what if B frees a pages everytime before pages_scanned
>> reaches the point, then we won't set zone->all_unreclaimable at all.
>> If so, we reaches a livelock here...
>
>
> If B keeps freeing pages, surely A will get a successful
> allocation and there will not be a livelock?
Ah, that is another piece of puzzle. We suspect the zone is under
min_watermark due to previous alloc_flags (ALLOC_NO_WATERMARKS) and B
returns the page under min which can not be allocated by A.
Now we reset the zone->pages_scanned on freeing page regardless of the
watermarks, so it is possible that zone is under min_watermark but
!zone->all_unreclaimable.
--Ying
>
> --
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next prev parent reply other threads:[~2012-04-24 17:17 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-23 20:56 [RFC PATCH] do_try_to_free_pages() might enter infinite loop Ying Han
2012-04-23 22:20 ` KOSAKI Motohiro
2012-04-23 23:18 ` Ying Han
2012-04-23 23:19 ` Ying Han
2012-04-24 1:31 ` Minchan Kim
2012-04-24 2:06 ` Ying Han
2012-04-24 16:36 ` Ying Han
2012-04-24 16:38 ` Rik van Riel
2012-04-24 16:45 ` KOSAKI Motohiro
2012-04-24 17:22 ` Ying Han
2012-04-24 17:17 ` Ying Han [this message]
2012-04-24 5:36 ` Nick Piggin
2012-04-24 18:37 ` Ying Han
2012-05-01 3:34 ` Nick Piggin
2012-05-01 16:18 ` Ying Han
2012-05-01 16:20 ` Ying Han
2012-05-01 17:06 ` Rik van Riel
2012-05-02 3:25 ` Nick Piggin
2012-06-11 23:33 ` KOSAKI Motohiro
2012-06-11 23:37 ` KOSAKI Motohiro
2012-06-14 5:25 ` Ying Han
2012-06-12 0:53 ` Rik van Riel
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