Messages in this thread Patch in this message | | | Date | Tue, 30 Jun 2009 17:34:57 +0100 | From | Mel Gorman <> | Subject | Re: BUG: Bad page state [was: Strange oopses in 2.6.30] |
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On Tue, Jun 30, 2009 at 09:31:04AM +0900, KOSAKI Motohiro wrote: > > -static inline int free_pages_check(struct page *page) > > -{ > > +static inline int free_pages_check(struct page *page, int wasMlocked) > > +{ > > + if (unlikely(wasMlocked)) { > > + WARN_ONCE(1, KERN_WARNING > > + "Page flag mlocked set for process %s at pfn:%05lx\n" > > + "page:%p flags:0x%lX\n", > > 0x%lX is a bit redundunt. > %lX insert "0x" string by itself, I think. >
/me slaps self
As hnaz pointed out to me on IRC, %#lX would have done the job of putting in the 0x automatically.
==== CUT HERE ==== mm: Warn once when a page is freed with PG_mlocked set
When a page is freed with the PG_mlocked set, it is considered an unexpected but recoverable situation. A counter records how often this event happens but it is easy to miss that this event has occured at all. This patch warns once when PG_mlocked is set to prompt debuggers to check the counter to see how often it is happening.
Signed-off-by: Mel Gorman <mel@csn.ul.ie> --- mm/page_alloc.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5d714f8..519ea6e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -495,8 +495,16 @@ static inline void free_page_mlock(struct page *page) static void free_page_mlock(struct page *page) { } #endif -static inline int free_pages_check(struct page *page) -{ +static inline int free_pages_check(struct page *page, int wasMlocked) +{ + if (unlikely(wasMlocked)) { + WARN_ONCE(1, KERN_WARNING + "Page flag mlocked set for process %s at pfn:%05lx\n" + "page:%p flags:%#lX\n", + current->comm, page_to_pfn(page), + page, page->flags|__PG_MLOCKED); + } + if (unlikely(page_mapcount(page) | (page->mapping != NULL) | (atomic_read(&page->_count) != 0) | @@ -562,7 +570,7 @@ static void __free_pages_ok(struct page *page, unsigned int order) kmemcheck_free_shadow(page, order); for (i = 0 ; i < (1 << order) ; ++i) - bad += free_pages_check(page + i); + bad += free_pages_check(page + i, wasMlocked); if (bad) return; @@ -1027,7 +1035,7 @@ static void free_hot_cold_page(struct page *page, int cold) if (PageAnon(page)) page->mapping = NULL; - if (free_pages_check(page)) + if (free_pages_check(page, wasMlocked)) return; if (!PageHighMem(page)) {
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