linux-kernel - [PATCH 1/2] mm/percpu.c: renew the max_contig if we merge the head and previous block

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Date:	Fri, 28 Mar 2014 20:55:21 +0800
From:	Jianyu Zhan <nasa4836@...il.com>
To:	linux-mm@...ck.org
Cc:	akpm@...ux-foundation.org, tj@...nel.org, cl@...ux-foundation.org,
	linux-kernel@...r.kernel.org, nasa4836@...il.com
Subject: [PATCH 1/2] mm/percpu.c: renew the max_contig if we merge the head and previous block

Hi, tj,
I've reworked the patches on top of percpu/for-3.15.

During pcpu_alloc_area(), we might merge the current head with the
previous block. Since we have calculated the max_contig using the
size of previous block before we skip it, and now we update the size
of previous block, so we should renew the max_contig.

Signed-off-by: Jianyu Zhan <nasa4836@...il.com>
---
 mm/percpu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index 202e104..63e24fb 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -473,9 +473,11 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
 		 * uncommon for percpu allocations.
 		 */
 		if (head && (head < sizeof(int) || !(p[-1] & 1))) {
+			*p = off += head;
 			if (p[-1] & 1)
 				chunk->free_size -= head;
-			*p = off += head;
+			else
+				max_contig = max(*p - p[-1], max_contig);
 			this_size -= head;
 			head = 0;
 		}
-- 
1.8.5.3

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