From b6b6783c8097f7561af6f9b4c6a6204040ad990f Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 22 Mar 2018 16:17:31 -0700 Subject: [PATCH] mm/thp: do not wait for lock_page() in deferred_split_scan() commit fa41b900c30b45fab03783724932dc30cd46a6be upstream. deferred_split_scan() gets called from reclaim path. Waiting for page lock may lead to deadlock there. Replace lock_page() with trylock_page() and skip the page if we failed to lock it. We will get to the page on the next scan. Link: http://lkml.kernel.org/r/20180315150747.31945-1-kirill.shutemov@linux.intel.com Fixes: 9a982250f773 ("thp: introduce deferred_split_huge_page()") Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/huge_memory.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index eba34cdfc3e5..a403d29da6fd 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2739,11 +2739,13 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, list_for_each_safe(pos, next, &list) { page = list_entry((void *)pos, struct page, mapping); - lock_page(page); + if (!trylock_page(page)) + goto next; /* split_huge_page() removes page from list on success */ if (!split_huge_page(page)) split++; unlock_page(page); +next: put_page(page); } -- 2.20.1