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From: Rik van Riel <riel@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Mel Gorman <mel@csn.ul.ie>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, Dave Chinner <david@fromorbit.com>,
	Chris Mason <chris.mason@oracle.com>,
	Nick Piggin <npiggin@suse.de>,
	Johannes Weiner <hannes@cmpxchg.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 12/12] vmscan: Do not writeback pages in direct reclaim
Date: Tue, 15 Jun 2010 10:02:07 -0400	[thread overview]
Message-ID: <4C1787DF.3020102@redhat.com> (raw)
In-Reply-To: <20100615133727.GA27980@infradead.org>

On 06/15/2010 09:37 AM, Christoph Hellwig wrote:
> On Tue, Jun 15, 2010 at 09:34:18AM -0400, Rik van Riel wrote:
>> If direct reclaim can overflow the stack, so can direct
>> memcg reclaim.  That means this patch does not solve the
>> stack overflow, while admitting that we do need the
>> ability to get specific pages flushed to disk from the
>> pageout code.
>
> Can you explain what the hell memcg reclaim is and why it needs
> to reclaim from random contexts?

The page fault code will call the cgroup accounting code.

When a cgroup goes over its memory limit, __mem_cgroup_try_charge
will call mem_cgroup_hierarchical_reclaim, which will then go
into the page reclaim code.

> It seems everything that has a cg in it's name that I stumbled over
> lately seems to be some ugly wart..

No argument there.  It took me a few minutes to find the code
path above :)

-- 
All rights reversed

WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Mel Gorman <mel@csn.ul.ie>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, Dave Chinner <david@fromorbit.com>,
	Chris Mason <chris.mason@oracle.com>,
	Nick Piggin <npiggin@suse.de>,
	Johannes Weiner <hannes@cmpxchg.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 12/12] vmscan: Do not writeback pages in direct reclaim
Date: Tue, 15 Jun 2010 10:02:07 -0400	[thread overview]
Message-ID: <4C1787DF.3020102@redhat.com> (raw)
In-Reply-To: <20100615133727.GA27980@infradead.org>

On 06/15/2010 09:37 AM, Christoph Hellwig wrote:
> On Tue, Jun 15, 2010 at 09:34:18AM -0400, Rik van Riel wrote:
>> If direct reclaim can overflow the stack, so can direct
>> memcg reclaim.  That means this patch does not solve the
>> stack overflow, while admitting that we do need the
>> ability to get specific pages flushed to disk from the
>> pageout code.
>
> Can you explain what the hell memcg reclaim is and why it needs
> to reclaim from random contexts?

The page fault code will call the cgroup accounting code.

When a cgroup goes over its memory limit, __mem_cgroup_try_charge
will call mem_cgroup_hierarchical_reclaim, which will then go
into the page reclaim code.

> It seems everything that has a cg in it's name that I stumbled over
> lately seems to be some ugly wart..

No argument there.  It took me a few minutes to find the code
path above :)

-- 
All rights reversed

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  parent reply	other threads:[~2010-06-15 14:38 UTC|newest]

Thread overview: 198+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-14 11:17 [PATCH 0/12] Avoid overflowing of stack during page reclaim V2 Mel Gorman
2010-06-14 11:17 ` Mel Gorman
2010-06-14 11:17 ` [PATCH 01/12] tracing, vmscan: Add trace events for kswapd wakeup, sleeping and direct reclaim Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 15:45   ` Rik van Riel
2010-06-14 15:45     ` Rik van Riel
2010-06-14 21:01   ` Larry Woodman
2010-06-14 21:01     ` Larry Woodman
2010-06-14 11:17 ` [PATCH 02/12] tracing, vmscan: Add trace events for LRU page isolation Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 16:47   ` Rik van Riel
2010-06-14 16:47     ` Rik van Riel
2010-06-14 21:02   ` Larry Woodman
2010-06-14 21:02     ` Larry Woodman
2010-06-14 11:17 ` [PATCH 03/12] tracing, vmscan: Add trace event when a page is written Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 16:48   ` Rik van Riel
2010-06-14 16:48     ` Rik van Riel
2010-06-14 21:02   ` Larry Woodman
2010-06-14 21:02     ` Larry Woodman
2010-06-14 11:17 ` [PATCH 04/12] tracing, vmscan: Add a postprocessing script for reclaim-related ftrace events Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 17:55   ` Rik van Riel
2010-06-14 17:55     ` Rik van Riel
2010-06-14 21:03   ` Larry Woodman
2010-06-14 21:03     ` Larry Woodman
2010-06-14 11:17 ` [PATCH 05/12] vmscan: kill prev_priority completely Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 18:04   ` Rik van Riel
2010-06-14 18:04     ` Rik van Riel
2010-06-16 23:37   ` Andrew Morton
2010-06-16 23:37     ` Andrew Morton
2010-06-16 23:45     ` Rik van Riel
2010-06-16 23:45       ` Rik van Riel
2010-06-17  0:18       ` Andrew Morton
2010-06-17  0:18         ` Andrew Morton
2010-06-17  0:34         ` Rik van Riel
2010-06-17  0:34           ` Rik van Riel
2010-06-25  8:29     ` KOSAKI Motohiro
2010-06-25  8:29       ` KOSAKI Motohiro
2010-06-28 10:35       ` Mel Gorman
2010-06-28 10:35         ` Mel Gorman
2010-06-14 11:17 ` [PATCH 06/12] vmscan: simplify shrink_inactive_list() Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 18:06   ` Rik van Riel
2010-06-14 18:06     ` Rik van Riel
2010-06-15 10:13     ` Mel Gorman
2010-06-15 10:13       ` Mel Gorman
2010-06-14 11:17 ` [PATCH 07/12] vmscan: Remove unnecessary temporary vars in do_try_to_free_pages Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 18:14   ` Rik van Riel
2010-06-14 18:14     ` Rik van Riel
2010-06-14 11:17 ` [PATCH 08/12] vmscan: Setup pagevec as late as possible in shrink_inactive_list() Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 18:59   ` Rik van Riel
2010-06-14 18:59     ` Rik van Riel
2010-06-15 10:47   ` Christoph Hellwig
2010-06-15 10:47     ` Christoph Hellwig
2010-06-15 15:56     ` Mel Gorman
2010-06-15 15:56       ` Mel Gorman
2010-06-16 23:43   ` Andrew Morton
2010-06-16 23:43     ` Andrew Morton
2010-06-17 10:30     ` Mel Gorman
2010-06-17 10:30       ` Mel Gorman
2010-06-14 11:17 ` [PATCH 09/12] vmscan: Setup pagevec as late as possible in shrink_page_list() Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 19:24   ` Rik van Riel
2010-06-14 19:24     ` Rik van Riel
2010-06-16 23:48   ` Andrew Morton
2010-06-16 23:48     ` Andrew Morton
2010-06-17 10:46     ` Mel Gorman
2010-06-17 10:46       ` Mel Gorman
2010-06-14 11:17 ` [PATCH 10/12] vmscan: Update isolated page counters outside of main path in shrink_inactive_list() Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 19:42   ` Rik van Riel
2010-06-14 19:42     ` Rik van Riel
2010-06-14 11:17 ` [PATCH 11/12] vmscan: Write out dirty pages in batch Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 21:13   ` Rik van Riel
2010-06-14 21:13     ` Rik van Riel
2010-06-15 10:18     ` Mel Gorman
2010-06-15 10:18       ` Mel Gorman
2010-06-14 23:11   ` Dave Chinner
2010-06-14 23:11     ` Dave Chinner
2010-06-14 23:21     ` Andrew Morton
2010-06-14 23:21       ` Andrew Morton
2010-06-15  0:39       ` Dave Chinner
2010-06-15  0:39         ` Dave Chinner
2010-06-15  1:16         ` Rik van Riel
2010-06-15  1:16           ` Rik van Riel
2010-06-15  1:45           ` Andrew Morton
2010-06-15  1:45             ` Andrew Morton
2010-06-15  4:08             ` Rik van Riel
2010-06-15  4:08               ` Rik van Riel
2010-06-15  4:37               ` Andrew Morton
2010-06-15  4:37                 ` Andrew Morton
2010-06-15  5:12                 ` Nick Piggin
2010-06-15  5:12                   ` Nick Piggin
2010-06-15  5:43                   ` [patch] mm: vmscan fix mapping use after free Nick Piggin
2010-06-15  5:43                     ` Nick Piggin
2010-06-15 13:23                     ` Mel Gorman
2010-06-15 13:23                       ` Mel Gorman
2010-06-15 11:01           ` [PATCH 11/12] vmscan: Write out dirty pages in batch Christoph Hellwig
2010-06-15 11:01             ` Christoph Hellwig
2010-06-15 13:32             ` Rik van Riel
2010-06-15 13:32               ` Rik van Riel
2010-06-15  1:39         ` Andrew Morton
2010-06-15  1:39           ` Andrew Morton
2010-06-15  3:20           ` Dave Chinner
2010-06-15  3:20             ` Dave Chinner
2010-06-15  4:15             ` Andrew Morton
2010-06-15  4:15               ` Andrew Morton
2010-06-15  6:36               ` Dave Chinner
2010-06-15  6:36                 ` Dave Chinner
2010-06-15 10:28                 ` Evgeniy Polyakov
2010-06-15 10:28                   ` Evgeniy Polyakov
2010-06-15 10:55                   ` Nick Piggin
2010-06-15 10:55                     ` Nick Piggin
2010-06-15 11:10                     ` Christoph Hellwig
2010-06-15 11:10                       ` Christoph Hellwig
2010-06-15 11:20                       ` Nick Piggin
2010-06-15 11:20                         ` Nick Piggin
2010-06-15 23:20                     ` Dave Chinner
2010-06-15 23:20                       ` Dave Chinner
2010-06-16  6:04                       ` Nick Piggin
2010-06-16  6:04                         ` Nick Piggin
2010-06-15 11:08                   ` Christoph Hellwig
2010-06-15 11:08                     ` Christoph Hellwig
2010-06-15 11:43               ` Mel Gorman
2010-06-15 11:43                 ` Mel Gorman
2010-06-15 13:07                 ` tytso
2010-06-15 13:07                   ` tytso
2010-06-15 15:44                 ` Mel Gorman
2010-06-15 15:44                   ` Mel Gorman
2010-06-15 10:57       ` Christoph Hellwig
2010-06-15 10:57         ` Christoph Hellwig
2010-06-15 10:53   ` Christoph Hellwig
2010-06-15 10:53     ` Christoph Hellwig
2010-06-15 11:11     ` Mel Gorman
2010-06-15 11:11       ` Mel Gorman
2010-06-15 11:13     ` Nick Piggin
2010-06-15 11:13       ` Nick Piggin
2010-06-14 11:17 ` [PATCH 12/12] vmscan: Do not writeback pages in direct reclaim Mel Gorman
2010-06-14 11:17   ` Mel Gorman
2010-06-14 21:55   ` Rik van Riel
2010-06-14 21:55     ` Rik van Riel
2010-06-15 11:45     ` Mel Gorman
2010-06-15 11:45       ` Mel Gorman
2010-06-15 13:34       ` Rik van Riel
2010-06-15 13:34         ` Rik van Riel
2010-06-15 13:37         ` Christoph Hellwig
2010-06-15 13:37           ` Christoph Hellwig
2010-06-15 13:54           ` Mel Gorman
2010-06-15 13:54             ` Mel Gorman
2010-06-16  0:30             ` KAMEZAWA Hiroyuki
2010-06-16  0:30               ` KAMEZAWA Hiroyuki
2010-06-15 14:02           ` Rik van Riel [this message]
2010-06-15 14:02             ` Rik van Riel
2010-06-15 13:59         ` Mel Gorman
2010-06-15 13:59           ` Mel Gorman
2010-06-15 14:04           ` Rik van Riel
2010-06-15 14:04             ` Rik van Riel
2010-06-15 14:16             ` Mel Gorman
2010-06-15 14:16               ` Mel Gorman
2010-06-16  0:17               ` KAMEZAWA Hiroyuki
2010-06-16  0:17                 ` KAMEZAWA Hiroyuki
2010-06-16  0:29                 ` Rik van Riel
2010-06-16  0:29                   ` Rik van Riel
2010-06-16  0:39                   ` KAMEZAWA Hiroyuki
2010-06-16  0:39                     ` KAMEZAWA Hiroyuki
2010-06-16  0:53                     ` Rik van Riel
2010-06-16  0:53                       ` Rik van Riel
2010-06-16  1:40                       ` KAMEZAWA Hiroyuki
2010-06-16  1:40                         ` KAMEZAWA Hiroyuki
2010-06-16  2:20                         ` KAMEZAWA Hiroyuki
2010-06-16  2:20                           ` KAMEZAWA Hiroyuki
2010-06-16  5:11                           ` Christoph Hellwig
2010-06-16  5:11                             ` Christoph Hellwig
2010-06-16 10:51                             ` Jens Axboe
2010-06-16 10:51                               ` Jens Axboe
2010-06-16  5:07                     ` Christoph Hellwig
2010-06-16  5:07                       ` Christoph Hellwig
2010-06-16  5:06                 ` Christoph Hellwig
2010-06-16  5:06                   ` Christoph Hellwig
2010-06-17  0:25                   ` KAMEZAWA Hiroyuki
2010-06-17  0:25                     ` KAMEZAWA Hiroyuki
2010-06-17  6:16                     ` Christoph Hellwig
2010-06-17  6:16                       ` Christoph Hellwig
2010-06-17  6:23                       ` KAMEZAWA Hiroyuki
2010-06-17  6:23                         ` KAMEZAWA Hiroyuki
2010-06-14 15:10 ` [PATCH 0/12] Avoid overflowing of stack during page reclaim V2 Christoph Hellwig
2010-06-14 15:10   ` Christoph Hellwig
2010-06-15 11:45   ` Mel Gorman
2010-06-15 11:45     ` Mel Gorman
2010-06-15  0:08 ` KAMEZAWA Hiroyuki
2010-06-15  0:08   ` KAMEZAWA Hiroyuki
2010-06-15 11:49   ` Mel Gorman
2010-06-15 11:49     ` Mel Gorman

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