Define page_file_cache() function to answer the question: is page backed by a file? Originally part of Rik van Riel's split-lru patch. Extracted to make available for other, independent reclaim patches. Moved inline function to linux/mm_inline.h where it will be needed by subsequent "split LRU" and "noreclaim" patches. Unfortunately this needs to use a page flag, since the PG_swapbacked state needs to be preserved all the way to the point where the page is last removed from the LRU. Trying to derive the status from other info in the page resulted in wrong VM statistics in earlier split VM patchsets. Signed-off-by: Rik van Riel Signed-off-by: Lee Schermerhorn Index: linux-2.6.25-mm1/include/linux/mm_inline.h =================================================================== --- linux-2.6.25-mm1.orig/include/linux/mm_inline.h 2008-04-24 10:46:43.000000000 -0400 +++ linux-2.6.25-mm1/include/linux/mm_inline.h 2008-04-24 12:00:01.000000000 -0400 @@ -1,3 +1,26 @@ +#ifndef LINUX_MM_INLINE_H +#define LINUX_MM_INLINE_H + +/** + * page_file_cache - should the page be on a file LRU or anon LRU? + * @page: the page to test + * + * Returns !0 if @page is page cache page backed by a regular filesystem, + * or 0 if @page is anonymous, tmpfs or otherwise ram or swap backed. + * + * We would like to get this info without a page flag, but the state + * needs to survive until the page is last deleted from the LRU, which + * could be as far down as __page_cache_release. + */ +static inline int page_file_cache(struct page *page) +{ + if (PageSwapBacked(page)) + return 0; + + /* The page is page cache backed by a normal filesystem. */ + return 2; +} + static inline void add_page_to_lru_list(struct zone *zone, struct page *page, enum lru_list l) { @@ -49,3 +72,4 @@ del_page_from_lru(struct zone *zone, str __dec_zone_state(zone, NR_INACTIVE + l); } +#endif Index: linux-2.6.25-mm1/mm/shmem.c =================================================================== --- linux-2.6.25-mm1.orig/mm/shmem.c 2008-04-22 10:33:45.000000000 -0400 +++ linux-2.6.25-mm1/mm/shmem.c 2008-04-24 12:00:01.000000000 -0400 @@ -1378,6 +1378,7 @@ repeat: goto failed; } + SetPageSwapBacked(filepage); spin_lock(&info->lock); entry = shmem_swp_alloc(info, idx, sgp); if (IS_ERR(entry)) Index: linux-2.6.25-mm1/include/linux/page-flags.h =================================================================== --- linux-2.6.25-mm1.orig/include/linux/page-flags.h 2008-04-22 10:33:44.000000000 -0400 +++ linux-2.6.25-mm1/include/linux/page-flags.h 2008-04-24 12:00:01.000000000 -0400 @@ -93,6 +93,7 @@ enum pageflags { PG_mappedtodisk, /* Has blocks allocated on-disk */ PG_reclaim, /* To be reclaimed asap */ PG_buddy, /* Page is free, on buddy lists */ + PG_swapbacked, /* Page is backed by RAM/swap */ #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR PG_uncached, /* Page has been mapped as uncached */ #endif @@ -160,6 +161,7 @@ PAGEFLAG(Pinned, owner_priv_1) TESTSCFLA PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved) PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private) __SETPAGEFLAG(Private, private) +PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked) /* * Only test-and-set exist for PG_writeback. The unconditional operators are Index: linux-2.6.25-mm1/mm/memory.c =================================================================== --- linux-2.6.25-mm1.orig/mm/memory.c 2008-04-22 10:33:45.000000000 -0400 +++ linux-2.6.25-mm1/mm/memory.c 2008-04-24 12:00:01.000000000 -0400 @@ -1756,6 +1756,7 @@ gotten: ptep_clear_flush(vma, address, page_table); set_pte_at(mm, address, page_table, entry); update_mmu_cache(vma, address, entry); + SetPageSwapBacked(new_page); lru_cache_add_active(new_page); page_add_new_anon_rmap(new_page, vma, address); @@ -2224,6 +2225,7 @@ static int do_anonymous_page(struct mm_s if (!pte_none(*page_table)) goto release; inc_mm_counter(mm, anon_rss); + SetPageSwapBacked(page); lru_cache_add_active(page); page_add_new_anon_rmap(page, vma, address); set_pte_at(mm, address, page_table, entry); @@ -2367,6 +2369,7 @@ static int __do_fault(struct mm_struct * set_pte_at(mm, address, page_table, entry); if (anon) { inc_mm_counter(mm, anon_rss); + SetPageSwapBacked(page); lru_cache_add_active(page); page_add_new_anon_rmap(page, vma, address); } else { Index: linux-2.6.25-mm1/mm/swap_state.c =================================================================== --- linux-2.6.25-mm1.orig/mm/swap_state.c 2008-04-22 10:33:45.000000000 -0400 +++ linux-2.6.25-mm1/mm/swap_state.c 2008-04-24 12:00:01.000000000 -0400 @@ -82,6 +82,7 @@ int add_to_swap_cache(struct page *page, if (!error) { page_cache_get(page); SetPageSwapCache(page); + SetPageSwapBacked(page); set_page_private(page, entry.val); total_swapcache_pages++; __inc_zone_page_state(page, NR_FILE_PAGES); Index: linux-2.6.25-mm1/mm/migrate.c =================================================================== --- linux-2.6.25-mm1.orig/mm/migrate.c 2008-04-24 11:59:51.000000000 -0400 +++ linux-2.6.25-mm1/mm/migrate.c 2008-04-24 12:00:01.000000000 -0400 @@ -546,6 +546,8 @@ static int move_to_new_page(struct page /* Prepare mapping for the new page.*/ newpage->index = page->index; newpage->mapping = page->mapping; + if (PageSwapBacked(page)) + SetPageSwapBacked(newpage); mapping = page_mapping(page); if (!mapping) Index: linux-2.6.25-mm1/mm/page_alloc.c =================================================================== --- linux-2.6.25-mm1.orig/mm/page_alloc.c 2008-04-24 10:46:43.000000000 -0400 +++ linux-2.6.25-mm1/mm/page_alloc.c 2008-04-24 12:00:01.000000000 -0400 @@ -261,6 +261,7 @@ static void bad_page(struct page *page) 1 << PG_slab | 1 << PG_swapcache | 1 << PG_writeback | + 1 << PG_swapbacked | 1 << PG_buddy ); set_page_count(page, 0); reset_page_mapcount(page); @@ -494,6 +495,8 @@ static inline int free_pages_check(struc bad_page(page); if (PageDirty(page)) __ClearPageDirty(page); + if (PageSwapBacked(page)) + __ClearPageSwapBacked(page); /* * For now, we report if PG_reserved was found set, but do not * clear it, and do not free the page. But we shall soon need @@ -644,6 +647,7 @@ static int prep_new_page(struct page *pa 1 << PG_swapcache | 1 << PG_writeback | 1 << PG_reserved | + 1 << PG_swapbacked | 1 << PG_buddy )))) bad_page(page); -- All Rights Reversed -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/