Commit f44d2198 authored Mar 21, 2012 by Xiao Guangrong Committed by Linus Torvalds Mar 21, 2012

mm: do not reset cached_hole_size when vma is unmapped



In the current code, cached_hole_size is set to the maximum value if the
unmapped vma is less that free_area_cache so the next search will search
from the base address.

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

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent cbde83e2

mm/mmap.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -1426,10 +1426,8 @@ 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;
		}
		}

		/*

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