linux-kernel - [PATCH 3/3] reuse __free_pages_exact() in __alloc_pages

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Message-Id: <20110414200141.09C3AA5F@kernel>
Date:	Thu, 14 Apr 2011 13:01:42 -0700
From:	Dave Hansen <dave@...ux.vnet.ibm.com>
To:	linux-mm@...ck.org
Cc:	linux-kernel@...r.kernel.org, Timur Tabi <timur@...escale.com>,
	Andi Kleen <andi@...stfloor.org>, Mel Gorman <mel@....ul.ie>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Michal Nazarewicz <mina86@...a86.com>,
	David Rientjes <rientjes@...gle.com>,
	Dave Hansen <dave@...ux.vnet.ibm.com>
Subject: [PATCH 3/3] reuse __free_pages_exact() in __alloc_pages_exact()


Michal Nazarewicz noticed that __alloc_pages_exact()'s
__free_page() loop was really close to something he was
using in one of his patches.   That made me realize that
it was actually very similar to __free_pages_exact().

This uses __free_pages_exact() in place of the loop
that we had in __alloc_pages_exact().  Since we had to
change the temporary variables around anyway, I gave
them some better names to hopefully address some other
review comments.

---

 linux-2.6.git-dave/mm/page_alloc.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff -puN mm/page_alloc.c~reuse-free-exact mm/page_alloc.c
--- linux-2.6.git/mm/page_alloc.c~reuse-free-exact	2011-04-14 12:03:10.132795021 -0700
+++ linux-2.6.git-dave/mm/page_alloc.c	2011-04-14 12:03:10.144795019 -0700
@@ -2338,14 +2338,11 @@ struct page *__alloc_pages_exact(gfp_t g
 
 	page = alloc_pages(gfp_mask, order);
 	if (page) {
-		struct page *alloc_end = page + (1 << order);
-		struct page *used = page + nr_pages;
+		struct page *unused_start = page + nr_pages;
+		unsigned long nr_unused = (1 << order) - nr_pages;
 
 		split_page(page, order);
-		while (used < alloc_end) {
-			__free_page(used);
-			used++;
-		}
+		__free_pages_exact(unused_start, nr_unused);
 	}
 
 	return page;
_
--
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