1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
2 From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
3 Date: Thu, 15 Mar 2018 18:07:47 +0300
4 Subject: [PATCH] mm/thp: Do not wait for lock_page() in deferred_split_scan()
6 Content-Type: text/plain; charset=UTF-8
7 Content-Transfer-Encoding: 8bit
9 deferred_split_scan() gets called from reclaim path. Waiting for page
10 lock may lead to deadlock there.
12 Replace lock_page() with trylock_page() and skip the page if we failed
13 to lock it. We will get to the page on the next scan.
15 Fixes: 9a982250f773 ("thp: introduce deferred_split_huge_page()")
17 Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
18 Acked-by: Michal Hocko <mhocko@suse.com>
19 (cherry-picked from https://patchwork.kernel.org/patch/10284703/)
20 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
22 mm/huge_memory.c | 4 +++-
23 1 file changed, 3 insertions(+), 1 deletion(-)
25 diff --git a/mm/huge_memory.c b/mm/huge_memory.c
26 index 8b887db33383..5c4093e0be8d 100644
27 --- a/mm/huge_memory.c
28 +++ b/mm/huge_memory.c
29 @@ -2621,11 +2621,13 @@ static unsigned long deferred_split_scan(struct shrinker *shrink,
31 list_for_each_safe(pos, next, &list) {
32 page = list_entry((void *)pos, struct page, mapping);
34 + if (!trylock_page(page))
36 /* split_huge_page() removes page from list on success */
37 if (!split_huge_page(page))