On Fri, Aug 23, 2013 at 06:30:39PM +0800, Wanpeng Li wrote: > v1 -> v2: > * add more explanation in patch description. > > 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. > > The trick here is migration type is MIGRATE_ISOLATE. There are other two parts > can change MIGRATE_ISOLATE except hwpoison. One is memory hoplug, however, we > hold lock_memory_hotplug() which avoid race. The second is CMA which umovable > page allocation requst can't fallback to. So it's safe here. > > Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx> > --- > 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 297965e..f357c91 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1426,7 +1426,8 @@ 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) > + set_migratetype_isolate(p, true); Do you really mean "we set MIGRATE_ISOLATE only if it's already set?" Thanks, Naoya Horiguchi > /* > * When the target page is a free hugepage, just remove it > * from free hugepage list. > -- > 1.8.1.2 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxx. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>