From 48c935ad88f5be20eb5445a77c171351b1eb5111 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Fri, 15 Jan 2016 16:51:24 -0800 Subject: page-flags: define PG_locked behavior on compound pages MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit lock_page() must operate on the whole compound page. It doesn't make much sense to lock part of compound page. Change code to use head page's PG_locked, if tail page is passed. This patch also gets rid of custom helper functions -- __set_page_locked() and __clear_page_locked(). They are replaced with helpers generated by __SETPAGEFLAG/__CLEARPAGEFLAG. Tail pages to these helper would trigger VM_BUG_ON(). SLUB uses PG_locked as a bit spin locked. IIUC, tail pages should never appear there. VM_BUG_ON() is added to make sure that this assumption is correct. [akpm@linux-foundation.org: fix fs/cifs/file.c] Signed-off-by: Kirill A. Shutemov Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Dave Hansen Cc: Mel Gorman Cc: Rik van Riel Cc: Vlastimil Babka Cc: Christoph Lameter Cc: Naoya Horiguchi Cc: Steve Capper Cc: "Aneesh Kumar K.V" Cc: Johannes Weiner Cc: Michal Hocko Cc: Jerome Marchand Cc: Jérôme Glisse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/page-flags.h | 2 +- include/linux/pagemap.h | 25 ++++++++----------------- 2 files changed, 9 insertions(+), 18 deletions(-) (limited to 'include') diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 12ab023b67f2..32c87eb470cb 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -256,7 +256,7 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; } #define TESTSCFLAG_FALSE(uname) \ TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname) -TESTPAGEFLAG(Locked, locked, PF_ANY) +__PAGEFLAG(Locked, locked, PF_NO_TAIL) PAGEFLAG(Error, error, PF_ANY) TESTCLEARFLAG(Error, error, PF_ANY) PAGEFLAG(Referenced, referenced, PF_ANY) TESTCLEARFLAG(Referenced, referenced, PF_ANY) __SETPAGEFLAG(Referenced, referenced, PF_ANY) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 26eabf5ec718..df214a4b886d 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -433,18 +433,9 @@ extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm, unsigned int flags); extern void unlock_page(struct page *page); -static inline void __set_page_locked(struct page *page) -{ - __set_bit(PG_locked, &page->flags); -} - -static inline void __clear_page_locked(struct page *page) -{ - __clear_bit(PG_locked, &page->flags); -} - static inline int trylock_page(struct page *page) { + page = compound_head(page); return (likely(!test_and_set_bit_lock(PG_locked, &page->flags))); } @@ -497,9 +488,9 @@ extern int wait_on_page_bit_killable_timeout(struct page *page, static inline int wait_on_page_locked_killable(struct page *page) { - if (PageLocked(page)) - return wait_on_page_bit_killable(page, PG_locked); - return 0; + if (!PageLocked(page)) + return 0; + return wait_on_page_bit_killable(compound_head(page), PG_locked); } extern wait_queue_head_t *page_waitqueue(struct page *page); @@ -518,7 +509,7 @@ static inline void wake_up_page(struct page *page, int bit) static inline void wait_on_page_locked(struct page *page) { if (PageLocked(page)) - wait_on_page_bit(page, PG_locked); + wait_on_page_bit(compound_head(page), PG_locked); } /* @@ -664,17 +655,17 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask); /* * Like add_to_page_cache_locked, but used to add newly allocated pages: - * the page is new, so we can just run __set_page_locked() against it. + * the page is new, so we can just run __SetPageLocked() against it. */ static inline int add_to_page_cache(struct page *page, struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask) { int error; - __set_page_locked(page); + __SetPageLocked(page); error = add_to_page_cache_locked(page, mapping, offset, gfp_mask); if (unlikely(error)) - __clear_page_locked(page); + __ClearPageLocked(page); return error; } -- cgit v1.2.3