linux-kernel - [PATCH 20/22] Get the pageblock migratetype without disabling interrupts

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Message-Id: <1240408407-21848-21-git-send-email-mel@csn.ul.ie>
Date:	Wed, 22 Apr 2009 14:53:25 +0100
From:	Mel Gorman <mel@....ul.ie>
To:	Mel Gorman <mel@....ul.ie>,
	Linux Memory Management List <linux-mm@...ck.org>
Cc:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Christoph Lameter <cl@...ux-foundation.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>,
	Pekka Enberg <penberg@...helsinki.fi>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH 20/22] 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 and interupts should never be disabled
longer than necessary. This patch checks the pagetype with interrupts
enabled with the impact that it is possible a page is freed to the wrong
list when a pageblock changes type. 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 6494e13..ba41551 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1034,6 +1034,7 @@ 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);
@@ -1043,7 +1044,6 @@ 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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