Messages in this thread | | | Date | Wed, 15 Jul 2009 13:56:52 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH] mm: Warn once when a page is freed with PG_mlocked set (resend) |
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On Wed, Jul 15, 2009 at 02:45:09PM +0200, Johannes Weiner wrote: > Hello Mel, > > On Wed, Jul 15, 2009 at 11:48:34AM +0100, Mel Gorman wrote: > > 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 caa9268..f8902e7 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:0x%lX\n", > > + current->comm, page_to_pfn(page), > > + page, page->flags|__PG_MLOCKED); > > Since the warning is the only action in this branch, wouldn't > WARN_ONCE(wasMlocked, KERN_WARNING ...) be better? >
It was to have the unlikely() but now that I look at WARN_ONCE(), it looks like it does the unlikely() part already. Will send another version. Thanks
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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