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From: Mel Gorman <mgorman@suse.de>
To: Linux-MM <linux-mm@kvack.org>,
	Linux-FSDevel <linux-fsdevel@vger.kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Vlastimil Babka <vbabka@suse.cz>, Jan Kara <jack@suse.cz>,
	Michal Hocko <mhocko@suse.cz>, Hugh Dickins <hughd@google.com>,
	Mel Gorman <mgorman@suse.de>,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: [PATCH 15/17] mm: Do not use unnecessary atomic operations when adding pages to the LRU
Date: Thu,  1 May 2014 09:44:46 +0100	[thread overview]
Message-ID: <1398933888-4940-16-git-send-email-mgorman@suse.de> (raw)
In-Reply-To: <1398933888-4940-1-git-send-email-mgorman@suse.de>

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
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>
---
 include/linux/swap.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index da8a250..395dcab 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -329,13 +329,15 @@ extern void add_page_to_unevictable_list(struct page *page);
  */
 static inline void lru_cache_add_anon(struct page *page)
 {
-	ClearPageActive(page);
+	if (PageActive(page))
+		ClearPageActive(page);
 	__lru_cache_add(page);
 }
 
 static inline void lru_cache_add_file(struct page *page)
 {
-	ClearPageActive(page);
+	if (PageActive(page))
+		ClearPageActive(page);
 	__lru_cache_add(page);
 }
 
-- 
1.8.4.5

  parent reply	other threads:[~2014-05-01  8:44 UTC|newest]

Thread overview: 57+ 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 ` [PATCH 01/17] mm: page_alloc: Do not update zlc unless the zlc is active Mel Gorman
2014-05-01 13:25   ` Johannes Weiner
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
2014-05-06 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
2014-05-06 15:10   ` Rik van Riel
2014-05-06 20:23   ` Peter Zijlstra
2014-05-06 22:21     ` Mel Gorman
2014-05-07  9:04       ` Peter Zijlstra
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
2014-05-06 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
2014-05-06 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
2014-05-06 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
2014-05-06 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
2014-05-02 22:34   ` Sasha Levin
2014-05-04 13:14     ` Mel Gorman
2014-05-05 12:40       ` Vlastimil Babka
2014-05-06  9:13         ` Mel Gorman
2014-05-06 14:42           ` Vlastimil Babka
2014-05-06 15:12             ` Mel Gorman
2014-05-06 20:34   ` Peter Zijlstra
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
2014-05-06 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
2014-05-06 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 14:35   ` Dave Hansen
2014-05-01 15:11     ` Mel Gorman
2014-05-01 15:38       ` Dave Hansen
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
2014-05-06 18:49   ` Rik van Riel
2014-05-01  8:44 ` [PATCH 13/17] mm: shmem: Avoid atomic operation during shmem_getpage_gfp Mel Gorman
2014-05-06 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 13:29   ` Johannes Weiner
2014-05-01 13:39     ` Mel Gorman
2014-05-01 13:47       ` Johannes Weiner
2014-05-06 18:54   ` Rik van Riel
2014-05-01  8:44 ` Mel Gorman [this message]
2014-05-01 13:33   ` [PATCH 15/17] mm: Do not use unnecessary atomic operations when adding pages to the LRU Johannes Weiner
2014-05-01 13:40     ` Mel Gorman
2014-05-06 15:30   ` Vlastimil Babka
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 ` [PATCH 17/17] mm: filemap: Avoid unnecessary barries and waitqueue lookup in unlock_page fastpath Mel Gorman
2014-05-05 10:50   ` Jan Kara
2014-05-07  9:03     ` Mel Gorman
2014-05-06 20:30   ` Peter Zijlstra

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