From 0be35096a145290cc0771d52adb3b241dca22604 Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Wed, 11 Sep 2013 14:22:55 -0700 Subject: [PATCH] mm/hwpoison: don't set migration type twice to avoid holding heavily contend zone->lock 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 Cc: Naoya Horiguchi Cc: Andi Kleen Cc: Tony Luck Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 c69217c07faa..784a1e17c905 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1429,7 +1429,8 @@ 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); /* * When the target page is a free hugepage, just remove it * from free hugepage list. -- 2.30.2