From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx169.postini.com [74.125.245.169]) by kanga.kvack.org (Postfix) with SMTP id 6B6876B0036 for ; Wed, 10 Apr 2013 14:24:21 -0400 (EDT) Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 10 Apr 2013 14:24:20 -0400 Received: from d01relay03.pok.ibm.com (d01relay03.pok.ibm.com [9.56.227.235]) by d01dlp03.pok.ibm.com (Postfix) with ESMTP id 88635C9008A for ; Wed, 10 Apr 2013 14:24:01 -0400 (EDT) Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r3AIO1aA269418 for ; Wed, 10 Apr 2013 14:24:01 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r3AIO0uI004737 for ; Wed, 10 Apr 2013 15:24:01 -0300 From: Cody P Schafer Subject: [PATCH v3 04/11] mm/page_alloc: protect pcp->batch accesses with ACCESS_ONCE Date: Wed, 10 Apr 2013 11:23:32 -0700 Message-Id: <1365618219-17154-5-git-send-email-cody@linux.vnet.ibm.com> In-Reply-To: <1365618219-17154-1-git-send-email-cody@linux.vnet.ibm.com> References: <1365618219-17154-1-git-send-email-cody@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Gilad Ben-Yossef , Simon Jeons , KOSAKI Motohiro , Mel Gorman , Linux MM , LKML , Cody P Schafer pcp->batch could change at any point, avoid relying on it being a stable value. Signed-off-by: Cody P Schafer --- mm/page_alloc.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f2929df..9dd0dc0 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1181,10 +1181,12 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp) { unsigned long flags; int to_drain; + unsigned long batch; local_irq_save(flags); - if (pcp->count >= pcp->batch) - to_drain = pcp->batch; + batch = ACCESS_ONCE(pcp->batch); + if (pcp->count >= batch) + to_drain = batch; else to_drain = pcp->count; if (to_drain > 0) { @@ -1352,8 +1354,9 @@ void free_hot_cold_page(struct page *page, int cold) list_add(&page->lru, &pcp->lists[migratetype]); pcp->count++; if (pcp->count >= pcp->high) { - free_pcppages_bulk(zone, pcp->batch, pcp); - pcp->count -= pcp->batch; + unsigned long batch = ACCESS_ONCE(pcp->batch); + free_pcppages_bulk(zone, batch, pcp); + pcp->count -= batch; } out: -- 1.8.2.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org