The patch titled
badpage: keep any bad page out of circulation
has been added to the -mm tree. Its filename is
badpage-keep-any-bad-page-out-of-circulation.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: keep any bad page out of circulation
From: Hugh Dickins <hugh@xxxxxxxxxxx>
Until now the bad_page() checkers have special-cased PageReserved, keeping
those pages out of circulation thereafter. Now extend the special case to
all: we want to keep ANY page with bad state out of circulation - the
"free" page may well be in use by something.
Leave the bad state of those pages untouched, for examination by
debuggers; except for PageBuddy - leaving that set would risk bringing the
page back.
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>
---
mm/page_alloc.c | 52 +++++++++++++++++++++-------------------------
1 file changed, 24 insertions(+), 28 deletions(-)
diff -puN mm/page_alloc.c~badpage-keep-any-bad-page-out-of-circulation mm/page_alloc.c
--- a/mm/page_alloc.c~badpage-keep-any-bad-page-out-of-circulation
+++ a/mm/page_alloc.c
@@ -231,9 +231,9 @@ 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();
- set_page_count(page, 0);
- reset_page_mapcount(page);
- page->mapping = NULL;
+
+ /* Leave bad fields for debug, except PageBuddy could make trouble */
+ __ClearPageBuddy(page);
add_taint(TAINT_BAD_PAGE);
}
@@ -290,25 +290,31 @@ void prep_compound_gigantic_page(struct
}
#endif
-static void destroy_compound_page(struct page *page, unsigned long order)
+static int destroy_compound_page(struct page *page, unsigned long order)
{
int i;
int nr_pages = 1 << order;
+ int bad = 0;
- if (unlikely(compound_order(page) != order))
+ if (unlikely(compound_order(page) != order) ||
+ unlikely(!PageHead(page))) {
bad_page(page);
+ bad++;
+ }
- if (unlikely(!PageHead(page)))
- bad_page(page);
__ClearPageHead(page);
+
for (i = 1; i < nr_pages; i++) {
struct page *p = page + i;
- if (unlikely(!PageTail(p) |
- (p->first_page != page)))
+ if (unlikely(!PageTail(p) | (p->first_page != page))) {
bad_page(page);
+ bad++;
+ }
__ClearPageTail(p);
}
+
+ return bad;
}
static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
@@ -428,7 +434,8 @@ static inline void __free_one_page(struc
int migratetype = get_pageblock_migratetype(page);
if (unlikely(PageCompound(page)))
- destroy_compound_page(page, order);
+ if (unlikely(destroy_compound_page(page, order)))
+ return;
page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
@@ -465,15 +472,10 @@ static inline int free_pages_check(struc
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
(page_count(page) != 0) |
- (page->flags & PAGE_FLAGS_CHECK_AT_FREE)))
+ (page->flags & PAGE_FLAGS_CHECK_AT_FREE))) {
bad_page(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.
- */
- if (PageReserved(page))
return 1;
+ }
if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
return 0;
@@ -521,11 +523,11 @@ static void __free_pages_ok(struct page
{
unsigned long flags;
int i;
- int reserved = 0;
+ int bad = 0;
for (i = 0 ; i < (1 << order) ; ++i)
- reserved += free_pages_check(page + i);
- if (reserved)
+ bad += free_pages_check(page + i);
+ if (bad)
return;
if (!PageHighMem(page)) {
@@ -610,17 +612,11 @@ static int prep_new_page(struct page *pa
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
(page_count(page) != 0) |
- (page->flags & PAGE_FLAGS_CHECK_AT_PREP)))
+ (page->flags & PAGE_FLAGS_CHECK_AT_PREP))) {
bad_page(page);
-
- /*
- * For now, we report if PG_reserved was found set, but do not
- * clear it, and do not allocate the page: as a safety net.
- */
- if (PageReserved(page))
return 1;
+ }
- 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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