Messages in this thread | | | Date | Wed, 20 Aug 2014 20:33:09 -0300 | From | Rafael Aquini <> | Subject | Re: [PATCH 2/7] mm/balloon_compaction: keep ballooned pages away from normal migration path |
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On Wed, Aug 20, 2014 at 07:04:40PM +0400, Konstantin Khlebnikov wrote: > Proper testing shows yet another problem in balloon migration: it works only > once for each page. balloon_page_movable() check page flags and page_count. > In __unmap_and_move page is locked, reference counter is elevated, so > balloon_page_movable() _always_ fails here. As result in __unmap_and_move() > migration goes to the normal migration path. > > Balloon ->migratepage() is so special, it returns MIGRATEPAGE_BALLOON_SUCCESS > instead of MIGRATEPAGE_SUCCESS. After that in move_to_new_page() successfully > migrated page got NULL into its mapping pointer and loses connectivity with > balloon and ability for further migration. > > It's safe to use __is_movable_balloon_page here: page is isolated and pinned. > > Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com> > Cc: stable <stable@vger.kernel.org> # v3.8 > --- > mm/migrate.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index f78ec9b..161d044 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -873,7 +873,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, > } > } > > - if (unlikely(balloon_page_movable(page))) { > + if (unlikely(__is_movable_balloon_page(page))) { > /* > * A ballooned page does not need any special attention from > * physical to virtual reverse mapping procedures. > Acked-by: Rafael Aquini <aquini@redhat.com>
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