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
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*** 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
--
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