The patch titled badpage: simplify page_alloc flag check+clear has been added to the -mm tree. Its filename is badpage-simplify-page_alloc-flag-checkclear.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: badpage: simplify page_alloc flag check+clear From: Hugh Dickins <hugh@xxxxxxxxxxx> Simplify the PAGE_FLAGS checking and clearing when freeing and allocating a page: check the same flags as before when freeing, clear ALL the flags (unless PageReserved) when freeing, check ALL flags off when allocating. Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx> Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/page-flags.h | 25 ++++++++----------------- mm/page_alloc.c | 19 ++++++------------- 2 files changed, 14 insertions(+), 30 deletions(-) diff -puN include/linux/page-flags.h~badpage-simplify-page_alloc-flag-checkclear include/linux/page-flags.h --- a/include/linux/page-flags.h~badpage-simplify-page_alloc-flag-checkclear +++ a/include/linux/page-flags.h @@ -375,31 +375,22 @@ static inline void __ClearPageTail(struc #define __PG_MLOCKED 0 #endif -#define PAGE_FLAGS (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \ - 1 << PG_buddy | 1 << PG_writeback | \ - 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ - __PG_UNEVICTABLE | __PG_MLOCKED) - -/* - * Flags checked in bad_page(). Pages on the free list should not have - * these flags set. It they are, there is a problem. - */ -#define PAGE_FLAGS_CLEAR_WHEN_BAD (PAGE_FLAGS | \ - 1 << PG_reclaim | 1 << PG_dirty | 1 << PG_swapbacked) - /* * Flags checked when a page is freed. Pages being freed should not have * these flags set. It they are, there is a problem. */ -#define PAGE_FLAGS_CHECK_AT_FREE (PAGE_FLAGS | 1 << PG_reserved) +#define PAGE_FLAGS_CHECK_AT_FREE \ + (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \ + 1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \ + 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ + __PG_UNEVICTABLE | __PG_MLOCKED) /* * Flags checked when a page is prepped for return by the page allocator. - * Pages being prepped should not have these flags set. It they are, there - * is a problem. + * Pages being prepped should not have any flags set. It they are set, + * there has been a kernel bug or struct page corruption. */ -#define PAGE_FLAGS_CHECK_AT_PREP (PAGE_FLAGS | \ - 1 << PG_reserved | 1 << PG_dirty | 1 << PG_swapbacked) +#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1) #endif /* !__GENERATING_BOUNDS_H */ #endif /* PAGE_FLAGS_H */ diff -puN mm/page_alloc.c~badpage-simplify-page_alloc-flag-checkclear mm/page_alloc.c --- a/mm/page_alloc.c~badpage-simplify-page_alloc-flag-checkclear +++ a/mm/page_alloc.c @@ -231,7 +231,6 @@ static void bad_page(struct page *page) printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n" KERN_EMERG "Backtrace:\n"); dump_stack(); - page->flags &= ~PAGE_FLAGS_CLEAR_WHEN_BAD; set_page_count(page, 0); reset_page_mapcount(page); page->mapping = NULL; @@ -468,16 +467,16 @@ static inline int free_pages_check(struc (page_count(page) != 0) | (page->flags & PAGE_FLAGS_CHECK_AT_FREE))) 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 * to do more, for when the ZERO_PAGE count wraps negative. */ - return PageReserved(page); + if (PageReserved(page)) + return 1; + if (page->flags & PAGE_FLAGS_CHECK_AT_PREP) + page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; + return 0; } /* @@ -621,13 +620,7 @@ static int prep_new_page(struct page *pa if (PageReserved(page)) return 1; - page->flags &= ~(1 << PG_uptodate | 1 << PG_error | 1 << PG_reclaim | - 1 << PG_referenced | 1 << PG_arch_1 | - 1 << PG_owner_priv_1 | 1 << PG_mappedtodisk -#ifdef CONFIG_UNEVICTABLE_LRU - | 1 << PG_mlocked -#endif - ); + page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; set_page_private(page, 0); set_page_refcounted(page); _ Patches currently in -mm which might be from hugh@xxxxxxxxxxx are ksym_symbol_len-fixes.patch linux-next.patch mm-dont-mark_page_accessed-in-shmem_fault.patch mm-apply_to_range-call-pte-function-with-lazy-updates.patch mm-remove-cgroup_mm_owner_callbacks.patch mm-remove-aop_writepage_activate.patch mm-remove-gfp_highuser_pagecache.patch mm-add-setclearpageswapcache-stubs.patch mm-replace-some-bug_ons-by-vm_bug_ons.patch mm-add_active_or_unevictable-into-rmap.patch mm-make-page_lock_anon_vma-static.patch mm-further-cleanup-page_add_new_anon_rmap.patch mm-gup-persist-for-write-permission.patch mm-wp-lock-page-before-deciding-cow.patch mm-reuse_swap_page-replaces-can_share_swap_page.patch mm-try_to_free_swap-replaces-remove_exclusive_swap_page.patch mm-try_to_unuse-check-removing-right-swap.patch mm-remove-try_to_munlock-from-vmscan.patch mm-remove-gfp_mask-from-add_to_swap.patch mm-add-add_to_swap-stub.patch mm-optimize-get_scan_ratio-for-no-swap.patch swapfile-swapon-needs-larger-size-type.patch swapfile-remove-swp_active-mask.patch swapfile-remove-surplus-whitespace.patch swapfile-remove-v0-swap-space-message.patch swapfile-rearrange-scan-and-swap_info.patch swapfile-swapon-use-discard-trim.patch swapfile-swap-allocation-use-discard.patch swapfile-swapon-randomize-if-nonrot.patch swapfile-swap-allocation-cycle-if-nonrot.patch swapfile-change-discard-pgoff_t-to-sector_t.patch swapfile-change-discard-pgoff_t-to-sector_t-fix.patch swapfile-let-others-seed-random.patch badpage-simplify-page_alloc-flag-checkclear.patch badpage-keep-any-bad-page-out-of-circulation.patch badpage-replace-page_remove_rmap-eeek-and-bug.patch badpage-vm_normal_page-use-print_bad_pte.patch badpage-zap-print_bad_pte-on-swap-and-file.patch badpage-remove-vma-from-page_remove_rmap.patch badpage-ratelimit-print_bad_pte-and-bad_page.patch badpage-kern_alert-bug-instead-of-kern_emerg.patch memcg-handle-swap-caches.patch memcg-handle-swap-caches-build-fix.patch memcg-swap-cgroup-for-remembering-usage.patch memcg-memswap-controller-core.patch memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch memcg-memswap-controller-core-swapcache-fixes.patch prio_tree-debugging-patch.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