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From: Johannes Weiner <hannes@cmpxchg.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Linux-MM <linux-mm@kvack.org>,
	Linux-FSDevel <linux-fsdevel@vger.kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>, Jan Kara <jack@suse.cz>,
	Michal Hocko <mhocko@suse.cz>, Hugh Dickins <hughd@google.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 15/17] mm: Do not use unnecessary atomic operations when adding pages to the LRU
Date: Thu, 1 May 2014 09:33:40 -0400	[thread overview]
Message-ID: <20140501133340.GE23420@cmpxchg.org> (raw)
In-Reply-To: <1398933888-4940-16-git-send-email-mgorman@suse.de>

On Thu, May 01, 2014 at 09:44:46AM +0100, Mel Gorman wrote:
> When adding pages to the LRU we clear the active bit unconditionally. As the
> page could be reachable from other paths we cannot use unlocked operations
> without risk of corruption such as a parallel mark_page_accessed. This
> patch test if is necessary to clear the atomic flag before using an atomic
> operation. In the unlikely even this races with mark_page_accesssed the

                             event

> consequences are simply that the page may be promoted to the active list
> that might have been left on the inactive list before the patch. This is
> a marginal consequence.
> 
> Signed-off-by: Mel Gorman <mgorman@suse.de>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

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WARNING: multiple messages have this Message-ID (diff)
From: Johannes Weiner <hannes@cmpxchg.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Linux-MM <linux-mm@kvack.org>,
	Linux-FSDevel <linux-fsdevel@vger.kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>, Jan Kara <jack@suse.cz>,
	Michal Hocko <mhocko@suse.cz>, Hugh Dickins <hughd@google.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 15/17] mm: Do not use unnecessary atomic operations when adding pages to the LRU
Date: Thu, 1 May 2014 09:33:40 -0400	[thread overview]
Message-ID: <20140501133340.GE23420@cmpxchg.org> (raw)
In-Reply-To: <1398933888-4940-16-git-send-email-mgorman@suse.de>

On Thu, May 01, 2014 at 09:44:46AM +0100, Mel Gorman wrote:
> When adding pages to the LRU we clear the active bit unconditionally. As the
> page could be reachable from other paths we cannot use unlocked operations
> without risk of corruption such as a parallel mark_page_accessed. This
> patch test if is necessary to clear the atomic flag before using an atomic
> operation. In the unlikely even this races with mark_page_accesssed the

                             event

> consequences are simply that the page may be promoted to the active list
> that might have been left on the inactive list before the patch. This is
> a marginal consequence.
> 
> Signed-off-by: Mel Gorman <mgorman@suse.de>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

  reply	other threads:[~2014-05-01 13:33 UTC|newest]

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-01  8:44 [PATCH 00/17] Misc page alloc, shmem, mark_page_accessed and page_waitqueue optimisations Mel Gorman
2014-05-01  8:44 ` Mel Gorman
2014-05-01  8:44 ` [PATCH 01/17] mm: page_alloc: Do not update zlc unless the zlc is active Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-01 13:25   ` Johannes Weiner
2014-05-01 13:25     ` Johannes Weiner
2014-05-06 15:04   ` Rik van Riel
2014-05-06 15:04     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 02/17] mm: page_alloc: Do not treat a zone that cannot be used for dirty pages as "full" Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 15:09   ` Rik van Riel
2014-05-06 15:09     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 03/17] mm: page_alloc: Use jump labels to avoid checking number_of_cpusets Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 15:10   ` Rik van Riel
2014-05-06 15:10     ` Rik van Riel
2014-05-06 20:23   ` Peter Zijlstra
2014-05-06 20:23     ` Peter Zijlstra
2014-05-06 22:21     ` Mel Gorman
2014-05-06 22:21       ` Mel Gorman
2014-05-07  9:04       ` Peter Zijlstra
2014-05-07  9:43         ` Mel Gorman
2014-05-07  9:43           ` Mel Gorman
2014-05-01  8:44 ` [PATCH 04/17] mm: page_alloc: Calculate classzone_idx once from the zonelist ref Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 16:01   ` Rik van Riel
2014-05-06 16:01     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 05/17] mm: page_alloc: Only check the zone id check if pages are buddies Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 16:48   ` Rik van Riel
2014-05-06 16:48     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 06/17] mm: page_alloc: Only check the alloc flags and gfp_mask for dirty once Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 17:24   ` Rik van Riel
2014-05-06 17:24     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 07/17] mm: page_alloc: Take the ALLOC_NO_WATERMARK check out of the fast path Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 17:25   ` Rik van Riel
2014-05-06 17:25     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 08/17] mm: page_alloc: Use word-based accesses for get/set pageblock bitmaps Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-02 22:34   ` Sasha Levin
2014-05-02 22:34     ` Sasha Levin
2014-05-04 13:14     ` Mel Gorman
2014-05-04 13:14       ` Mel Gorman
2014-05-05 12:40       ` Vlastimil Babka
2014-05-05 12:40         ` Vlastimil Babka
2014-05-06  9:13         ` Mel Gorman
2014-05-06  9:13           ` Mel Gorman
2014-05-06 14:42           ` Vlastimil Babka
2014-05-06 14:42             ` Vlastimil Babka
2014-05-06 15:12             ` Mel Gorman
2014-05-06 15:12               ` Mel Gorman
2014-05-06 20:34   ` Peter Zijlstra
2014-05-06 20:34     ` Peter Zijlstra
2014-05-06 22:24     ` Mel Gorman
2014-05-06 22:24       ` Mel Gorman
2014-05-01  8:44 ` [PATCH 09/17] mm: page_alloc: Reduce number of times page_to_pfn is called Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 18:47   ` Rik van Riel
2014-05-06 18:47     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 10/17] mm: page_alloc: Lookup pageblock migratetype with IRQs enabled during free Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 18:48   ` Rik van Riel
2014-05-06 18:48     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 11/17] mm: page_alloc: Use unsigned int for order in more places Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-01 14:35   ` Dave Hansen
2014-05-01 14:35     ` Dave Hansen
2014-05-01 15:11     ` Mel Gorman
2014-05-01 15:11       ` Mel Gorman
2014-05-01 15:38       ` Dave Hansen
2014-05-01 15:38         ` Dave Hansen
2014-05-06 18:49   ` Rik van Riel
2014-05-06 18:49     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 12/17] mm: page_alloc: Convert hot/cold parameter and immediate callers to bool Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 18:49   ` Rik van Riel
2014-05-06 18:49     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 13/17] mm: shmem: Avoid atomic operation during shmem_getpage_gfp Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-06 18:53   ` Rik van Riel
2014-05-06 18:53     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 14/17] mm: Do not use atomic operations when releasing pages Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-01 13:29   ` Johannes Weiner
2014-05-01 13:29     ` Johannes Weiner
2014-05-01 13:39     ` Mel Gorman
2014-05-01 13:39       ` Mel Gorman
2014-05-01 13:47       ` Johannes Weiner
2014-05-01 13:47         ` Johannes Weiner
2014-05-06 18:54   ` Rik van Riel
2014-05-06 18:54     ` Rik van Riel
2014-05-01  8:44 ` [PATCH 15/17] mm: Do not use unnecessary atomic operations when adding pages to the LRU Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-01 13:33   ` Johannes Weiner [this message]
2014-05-01 13:33     ` Johannes Weiner
2014-05-01 13:40     ` Mel Gorman
2014-05-01 13:40       ` Mel Gorman
2014-05-06 15:30   ` Vlastimil Babka
2014-05-06 15:30     ` Vlastimil Babka
2014-05-06 15:55     ` Mel Gorman
2014-05-06 15:55       ` Mel Gorman
2014-05-01  8:44 ` [PATCH 16/17] mm: Non-atomically mark page accessed during page cache allocation where possible Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-01  8:44 ` [PATCH 17/17] mm: filemap: Avoid unnecessary barries and waitqueue lookup in unlock_page fastpath Mel Gorman
2014-05-01  8:44   ` Mel Gorman
2014-05-05 10:50   ` Jan Kara
2014-05-05 10:50     ` Jan Kara
2014-05-07  9:03     ` Mel Gorman
2014-05-07  9:03       ` Mel Gorman
2014-05-06 20:30   ` Peter Zijlstra
2014-05-06 20:30     ` Peter Zijlstra

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