Messages in this thread |  | | | Date | Mon, 6 Jun 2011 11:39:24 +0100 | | From | Mel Gorman <> | | Subject | Re: [PATCH] mm: compaction: Abort compaction if too many pages are isolated and caller is asynchronous |
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On Fri, Jun 03, 2011 at 05:45:54PM +0200, Andrea Arcangeli wrote: > On Fri, Jun 03, 2011 at 03:49:41PM +0100, Mel Gorman wrote: > > Right idea of the wrong zone being accounted for but wrong place. I > > think the following patch should fix the problem; > > Looks good thanks. > > I also found this bug during my debugging that made NR_SHMEM underflow. > > === > Subject: migrate: don't account swapcache as shmem > > From: Andrea Arcangeli <aarcange@redhat.com> > > swapcache will reach the below code path in migrate_page_move_mapping, > and swapcache is accounted as NR_FILE_PAGES but it's not accounted as > NR_SHMEM. > > Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Well spotted.
Acked-by: Mel Gorman <mgorman@suse.de>
Minor nit. swapper_space is rarely referred to outside of the swap code. Might it be more readable to use
/* * swapcache is accounted as NR_FILE_PAGES but it is not * accounted as NR_SHMEM * if (PageSwapBacked(page) && !PageSwapCache(page)) ?
> --- > > diff --git a/mm/migrate.c b/mm/migrate.c > index e4a5c91..2597a27 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -288,7 +288,7 @@ static int migrate_page_move_mapping(struct address_space *mapping, > */ > __dec_zone_page_state(page, NR_FILE_PAGES); > __inc_zone_page_state(newpage, NR_FILE_PAGES); > - if (PageSwapBacked(page)) { > + if (mapping != &swapper_space && PageSwapBacked(page)) { > __dec_zone_page_state(page, NR_SHMEM); > __inc_zone_page_state(newpage, NR_SHMEM); > } > >
-- Mel Gorman SUSE Labs
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