Subject: [merged] mm-correct-the-comment-about-the-value-for-buddy-_mapcount.patch removed from -mm tree To: shhuiw@xxxxxxxxx,mel@xxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Thu, 12 Sep 2013 12:45:17 -0700 The patch titled Subject: mm: correct the comment about the value for buddy _mapcount has been removed from the -mm tree. Its filename was mm-correct-the-comment-about-the-value-for-buddy-_mapcount.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Wang Sheng-Hui <shhuiw@xxxxxxxxx> Subject: mm: correct the comment about the value for buddy _mapcount Set _mapcount PAGE_BUDDY_MAPCOUNT_VALUE to make the page buddy. Not the magic number -2. Signed-off-by: Wang Sheng-Hui <shhuiw@xxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff -puN mm/page_alloc.c~mm-correct-the-comment-about-the-value-for-buddy-_mapcount mm/page_alloc.c --- a/mm/page_alloc.c~mm-correct-the-comment-about-the-value-for-buddy-_mapcount +++ a/mm/page_alloc.c @@ -489,8 +489,10 @@ __find_buddy_index(unsigned long page_id * (c) a page and its buddy have the same order && * (d) a page and its buddy are in the same zone. * - * For recording whether a page is in the buddy system, we set ->_mapcount -2. - * Setting, clearing, and testing _mapcount -2 is serialized by zone->lock. + * For recording whether a page is in the buddy system, we set ->_mapcount + * PAGE_BUDDY_MAPCOUNT_VALUE. + * Setting, clearing, and testing _mapcount PAGE_BUDDY_MAPCOUNT_VALUE is + * serialized by zone->lock. * * For recording page's order, we use page_private(page). */ @@ -528,8 +530,9 @@ static inline int page_is_buddy(struct p * as necessary, plus some accounting needed to play nicely with other * parts of the VM system. * At each level, we keep a list of pages, which are heads of continuous - * free pages of length of (1 << order) and marked with _mapcount -2. Page's - * order is recorded in page_private(page) field. + * free pages of length of (1 << order) and marked with _mapcount + * PAGE_BUDDY_MAPCOUNT_VALUE. Page's order is recorded in page_private(page) + * field. * So when we are allocating or freeing one, we can derive the state of the * other. That is, if we allocate a small block, and both were * free, the remainder of the region must be split into blocks. _ Patches currently in -mm which might be from shhuiw@xxxxxxxxx are origin.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html