linux-kernel - [PATCH 26/27] Get the pageblock migratetype without disabling interrupts

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Message-Id: <1237226020-14057-27-git-send-email-mel@csn.ul.ie>
Date:	Mon, 16 Mar 2009 17:53:40 +0000
From:	Mel Gorman <mel@....ul.ie>
To:	Mel Gorman <mel@....ul.ie>,
	Linux Memory Management List <linux-mm@...ck.org>
Cc:	Pekka Enberg <penberg@...helsinki.fi>,
	Rik van Riel <riel@...hat.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Johannes Weiner <hannes@...xchg.org>,
	Nick Piggin <npiggin@...e.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Lin Ming <ming.m.lin@...el.com>,
	Zhang Yanmin <yanmin_zhang@...ux.intel.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH 26/27] Get the pageblock migratetype without disabling interrupts

Local interrupts are disabled when freeing pages to the PCP list. Part
of that free checks what the migratetype of the pageblock the page is in
but it checks this with interrupts disabled. This patch checks the
pagetype with interrupts enabled. The impact is that it is possible a
page is freed to the wrong list when a pageblock changes type but as
that block is now already considered mixed from an anti-fragmentation
perspective, it's not of vital importance.

Signed-off-by: Mel Gorman <mel@....ul.ie>
---
 mm/page_alloc.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f71091a..ca7bc04 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1039,6 +1039,7 @@ static void free_hot_cold_page(struct page *page, int cold)
 	kernel_map_pages(page, 1, 0);
 
 	pcp = &zone_pcp(zone, get_cpu())->pcp;
+	set_page_private(page, get_pageblock_migratetype(page));
 	local_irq_save(flags);
 	if (unlikely(clearMlocked))
 		free_page_mlock(page);
@@ -1048,7 +1049,6 @@ static void free_hot_cold_page(struct page *page, int cold)
 		list_add_tail(&page->lru, &pcp->list);
 	else
 		list_add(&page->lru, &pcp->list);
-	set_page_private(page, get_pageblock_migratetype(page));
 	pcp->count++;
 	if (pcp->count >= pcp->high) {
 		free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
-- 
1.5.6.5

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