On Thu, Nov 06, 2014 at 04:09:08PM +0800, Weijie Yang wrote: > If race between isolatation and allocation happens, we could need to move > some freepages to MIGRATE_ISOLATE in __test_page_isolated_in_pageblock(). > The current code ignores the zone_freepage accounting after the move, > which cause the zone NR_FREE_PAGES and NR_FREE_CMA_PAGES statistics incorrect. > > This patch fixes this rare issue.
Hello, After "fix freepage count problems in memory isolation" merged, this race should not happen. I have to remove it in that patchset, but, I forgot to remove it. Please remove this race handling code completely and tag with stable. If we don't remove it, there is errornous situation because get_freepage_migratetype() could return invalid migratetype although the page is on the correct buddy list. So, we regard no race situation as race one. Thanks. > > Signed-off-by: Weijie Yang <[email protected]> > --- > mm/page_isolation.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/mm/page_isolation.c b/mm/page_isolation.c > index 3ddc8b3..15b51de 100644 > --- a/mm/page_isolation.c > +++ b/mm/page_isolation.c > @@ -193,12 +193,15 @@ __test_page_isolated_in_pageblock(unsigned long pfn, > unsigned long end_pfn, > * is MIGRATE_ISOLATE. Catch it and move the page into > * MIGRATE_ISOLATE list. > */ > - if (get_freepage_migratetype(page) != MIGRATE_ISOLATE) { > + int migratetype = get_freepage_migratetype(page); > + if (migratetype != MIGRATE_ISOLATE) { > struct page *end_page; > > end_page = page + (1 << page_order(page)) - 1; > move_freepages(page_zone(page), page, end_page, > MIGRATE_ISOLATE); > + __mod_zone_freepage_state(zone, > + -(1 << page_order(page)), migratetype); > } > pfn += 1 << page_order(page); > } > -- > 1.7.0.4 > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to [email protected]. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"[email protected]";> [email protected] </a> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
