linux-kernel - [PATCH 4/5] mm: do not reset cached_hole

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Message-ID: <4F1019B0.5080503@linux.vnet.ibm.com>
Date:	Fri, 13 Jan 2012 19:46:56 +0800
From:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
To:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	William Irwin <wli@...omorphy.com>, linux-mm@...ck.org,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 4/5] mm: do not reset cached_hole_size when vma is unmapped

In current code, cached_hole_size is set to the maximal value if the unmapped
vma is under free_area_cache, next search will search from the base addr

Actually, we can keep cached_hole_size so that if next required size is more
that cached_hole_size, it can search from free_area_cache

Signed-off-by: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
---
 mm/mmap.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 3f758c7..970f572 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1423,10 +1423,8 @@ void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
 	/*
 	 * Is this a new hole at the lowest possible address?
 	 */
-	if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
+	if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache)
 		mm->free_area_cache = addr;
-		mm->cached_hole_size = ~0UL;
-	}
 }

 /*
-- 
1.7.7.5

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