On Thu, Aug 22, 2013 at 05:48:25PM +0800, Wanpeng Li wrote: > Set pageblock migration type will hold zone->lock which is heavy contended > in system to avoid race. However, soft offline page will set pageblock > migration type twice during get page if the page is in used, not hugetlbfs > page and not on lru list. There is unnecessary to set the pageblock migration > type and hold heavy contended zone->lock again if the first round get page > have already set the pageblock to right migration type.
Can we use get_pageblock_migratetype() outside zone->lock? There are surely some users which call this function outside zone->lock like free_hot_cold_pages(), __free_pages, etc., but I think that there's a race window where migratetype is updated just after get_pageblock_migratetype() check. > Signed-off-by: Wanpeng Li <liw...@linux.vnet.ibm.com> > --- > mm/memory-failure.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 6bfd51e..3bfb45f 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1413,7 +1413,8 @@ static int __get_any_page(struct page *p, unsigned long > pfn, int flags) > * was free. This flag should be kept set until the source page > * is freed and PG_hwpoison on it is set. > */ > - set_migratetype_isolate(p, true); > + if (get_pageblock_migratetype(p) == MIGRATE_ISOLATE) You meant '!=', right? Thanks, Naoya Horiguchi > + set_migratetype_isolate(p, true); > /* > * When the target page is a free hugepage, just remove it > * from free hugepage list. > -- > 1.8.1.2 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
