hugetlb: decrease hugetlb_lock cycling in gather_surplus_huge_pages
commit19fc3f0acde32636529969570055c7e2a744787c
authorAdam Litke <agl@us.ibm.com>
Mon, 28 Apr 2008 09:12:20 +0000 (28 02:12 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 28 Apr 2008 15:58:19 +0000 (28 08:58 -0700)
treeabcd29adbebe027eb2f3f13770e63662c22c7975
parent797df5749032c2286bc7ff3a52de41fde0cdf0a5
hugetlb: decrease hugetlb_lock cycling in gather_surplus_huge_pages

To reduce hugetlb_lock acquisitions and releases when freeing excess surplus
pages, scan the page list in two parts.  First, transfer the needed pages to
the hugetlb pool.  Then drop the lock and free the remaining pages back to the
buddy allocator.

In the common case there are zero excess pages and no lock operations are
required.

Thanks Mel Gorman for this improvement.

Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/hugetlb.c