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From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	stable@kernel.org
Cc: Rik van Riel <riel@redhat.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Elladan <elladan@eskimo.com>, Nick Piggin <npiggin@suse.de>,
	Andi Kleen <andi@firstfloor.org>,
	Christoph Lameter <cl@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Minchan Kim <minchan.kim@gmail.com>
Subject: [PATCH][BUGFIX] vmscan: limit VM_EXEC protection to file pages
Date: Tue, 13 Oct 2009 16:00:54 +0800	[thread overview]
Message-ID: <20091013080054.GA20395@localhost> (raw)
In-Reply-To: <4AD3E6C4.805@redhat.com>

It is possible to have !Anon but SwapBacked pages, and some apps could
create huge number of such pages with MAP_SHARED|MAP_ANONYMOUS. These
pages go into the ANON lru list, and hence shall not be protected: we
only care mapped executable files. Failing to do so may trigger OOM.

Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 mm/vmscan.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux.orig/mm/vmscan.c	2009-10-13 09:49:05.000000000 +0800
+++ linux/mm/vmscan.c	2009-10-13 09:49:37.000000000 +0800
@@ -1356,7 +1356,7 @@ static void shrink_active_list(unsigned 
 			 * IO, plus JVM can create lots of anon VM_EXEC pages,
 			 * so we ignore them here.
 			 */
-			if ((vm_flags & VM_EXEC) && !PageAnon(page)) {
+			if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) {
 				list_add(&page->lru, &l_active);
 				continue;
 			}

  reply	other threads:[~2009-10-13  8:01 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-12 20:44 oomkiller over-ambitious after "vmscan: make mapped executable pages the first class citizen" (bisected) Christian Borntraeger
2009-10-12 21:17 ` Peter Zijlstra
2009-10-13  2:26 ` Wu Fengguang
2009-10-13  2:32   ` Rik van Riel
2009-10-13  8:00     ` Wu Fengguang [this message]
2009-10-13  8:03       ` [PATCH][BUGFIX] vmscan: limit VM_EXEC protection to file pages Wu Fengguang
2009-10-13 11:33       ` Hugh Dickins
2009-10-13  5:50   ` oomkiller over-ambitious after "vmscan: make mapped executable pages the first class citizen" (bisected) Christian Borntraeger

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