From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx125.postini.com [74.125.245.125]) by kanga.kvack.org (Postfix) with SMTP id 09EC76B003A for ; Fri, 30 Aug 2013 04:43:29 -0400 (EDT) Received: from eucpsbgm1.samsung.com (unknown [203.254.199.244]) by mailout3.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0MSC00FVQ5K8X990@mailout3.w1.samsung.com> for linux-mm@kvack.org; Fri, 30 Aug 2013 09:43:28 +0100 (BST) From: Krzysztof Kozlowski Subject: [RFC PATCH 2/4] mm: use mapcount for identifying zbud pages Date: Fri, 30 Aug 2013 10:42:54 +0200 Message-id: <1377852176-30970-3-git-send-email-k.kozlowski@samsung.com> In-reply-to: <1377852176-30970-1-git-send-email-k.kozlowski@samsung.com> References: <1377852176-30970-1-git-send-email-k.kozlowski@samsung.com> Sender: owner-linux-mm@kvack.org List-ID: To: Seth Jennings , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton Cc: Bob Liu , Mel Gorman , Bartlomiej Zolnierkiewicz , Marek Szyprowski , Kyungmin Park , Dave Hansen , Minchan Kim , Krzysztof Kozlowski Currently zbud pages do not have any flags set so it is not possible to identify them during migration or compaction. Implement PageZbud() by comparing page->_mapcount to -127 to distinguish pages allocated by zbud. Just like PageBuddy() is implemented. Signed-off-by: Krzysztof Kozlowski --- include/linux/mm.h | 23 +++++++++++++++++++++++ mm/zbud.c | 4 ++++ 2 files changed, 27 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index f022460..b9ae6f2 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -440,6 +440,7 @@ static inline void init_page_count(struct page *page) * efficiently by most CPU architectures. */ #define PAGE_BUDDY_MAPCOUNT_VALUE (-128) +#define PAGE_ZBUD_MAPCOUNT_VALUE (-127) static inline int PageBuddy(struct page *page) { @@ -458,6 +459,28 @@ static inline void __ClearPageBuddy(struct page *page) atomic_set(&page->_mapcount, -1); } +#ifdef CONFIG_ZBUD +static inline int PageZbud(struct page *page) +{ + return atomic_read(&page->_mapcount) == PAGE_ZBUD_MAPCOUNT_VALUE; +} + +static inline void SetPageZbud(struct page *page) +{ + VM_BUG_ON(atomic_read(&page->_mapcount) != -1); + atomic_set(&page->_mapcount, PAGE_ZBUD_MAPCOUNT_VALUE); +} + +static inline void ClearPageZbud(struct page *page) +{ + VM_BUG_ON(!PageZbud(page)); + atomic_set(&page->_mapcount, -1); +} +#else +PAGEFLAG_FALSE(Zbud) +#endif + + void put_page(struct page *page); void put_pages_list(struct list_head *pages); diff --git a/mm/zbud.c b/mm/zbud.c index aa9a15c..9267cd9 100644 --- a/mm/zbud.c +++ b/mm/zbud.c @@ -197,7 +197,10 @@ static void get_zbud_page(struct zbud_header *zhdr) static int put_zbud_page(struct zbud_header *zhdr) { struct page *page = virt_to_page(zhdr); + VM_BUG_ON(!PageZbud(page)); + if (put_page_testzero(page)) { + ClearPageZbud(page); free_hot_cold_page(page, 0); return 1; } @@ -307,6 +310,7 @@ int zbud_alloc(struct zbud_pool *pool, int size, gfp_t gfp, * don't increase the page count. */ zhdr = init_zbud_page(page); + SetPageZbud(page); bud = FIRST; found: -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org