@@ -51,6 +54,66 @@ extern void compaction_defer_reset(struct zone *zone, int order, bool alloc_success); extern bool compaction_restarting(struct zone *zone, int order);+static inline bool mobile_page(struct page *page) +{ + return page->mapping && page->mapping->a_ops &&Dereferncing mapping->a_ops isn't safe without page-lock and isn't required: all mappings always have ->a_ops.
I got it.
+static inline void putback_mobilepage(struct page *page) +{ + /* + * 'lock_page()' stabilizes the page and prevents races against + * concurrent isolation threads attempting to re-isolate it. + */ + lock_page(page); + if (mobile_page(page) && page->mapping->a_ops->putbackpage) {It seems "if (page->mapping && page->mapping->a_ops->putbackpage)" should be enough: we already seen that page as mobile.
Ditto.
+ page->mapping->a_ops->putbackpage(page); + /* drop the extra ref count taken for mobile page isolation */ + put_page(page); + } + unlock_page(page);call put_page() after unlock and do that always -- putback must drop page reference from caller. lock_page(page); if (page->mapping && page->mapping->a_ops->putbackpage) page->mapping->a_ops->putbackpage(page); unlock_page(); put_page(page);
Ditto.
+} #else static inline unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order, int alloc_flags, @@ -83,6 +146,19 @@ static inline bool compaction_deferred(struct zone *zone, int order) return true; } +static inline bool mobile_page(struct page *page) +{ + return false; +} + +static inline bool isolate_mobilepage(struct page *page, isolate_mode_t mode) +{ + return false; +} + +static inline void putback_mobilepage(struct page *page) +{ +} #endif /* CONFIG_COMPACTION */ #if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) diff --git a/include/linux/fs.h b/include/linux/fs.h index 35ec87e..33c9aa5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -395,6 +395,8 @@ struct address_space_operations { */ int (*migratepage) (struct address_space *, struct page *, struct page *, enum migrate_mode); + bool (*isolatepage) (struct page *, isolate_mode_t); + void (*putbackpage) (struct page *); int (*launder_page) (struct page *); int (*is_partially_uptodate) (struct page *, unsigned long, unsigned long); diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index f34e040..abef145 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -582,6 +582,25 @@ static inline void __ClearPageBalloon(struct page *page) atomic_set(&page->_mapcount, -1); } +#define PAGE_MOBILE_MAPCOUNT_VALUE (-255) + +static inline int PageMobile(struct page *page) +{ + return atomic_read(&page->_mapcount) == PAGE_MOBILE_MAPCOUNT_VALUE; +} + +static inline void __SetPageMobile(struct page *page) +{ + VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page); + atomic_set(&page->_mapcount, PAGE_MOBILE_MAPCOUNT_VALUE); +} + +static inline void __ClearPageMobile(struct page *page) +{ + VM_BUG_ON_PAGE(!PageMobile(page), page); + atomic_set(&page->_mapcount, -1); +} + /* * If network-based swap is enabled, sl*b must keep track of whether pages * were allocated from pfmemalloc reserves. diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h index a6c4962..d50d9e8 100644 --- a/include/uapi/linux/kernel-page-flags.h +++ b/include/uapi/linux/kernel-page-flags.h @@ -33,6 +33,7 @@ #define KPF_THP 22 #define KPF_BALLOON 23 #define KPF_ZERO_PAGE 24 +#define KPF_MOBILE 25 #endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */ -- 2.1.4
I fixed the code as your comments and I found patch 3/5 and 4/5 could not be applied separately. So I merge them and report new [PATCH]. I appreciate your reviews. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
