From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752728AbeCOPH4 (ORCPT ); Thu, 15 Mar 2018 11:07:56 -0400 Received: from mga12.intel.com ([192.55.52.136]:2160 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752557AbeCOPHz (ORCPT ); Thu, 15 Mar 2018 11:07:55 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,311,1517904000"; d="scan'208";a="37684200" From: "Kirill A. Shutemov" To: Andrew Morton Cc: Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCH] mm/thp: Do not wait for lock_page() in deferred_split_scan() Date: Thu, 15 Mar 2018 18:07:47 +0300 Message-Id: <20180315150747.31945-1-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.16.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Kirill A. Shutemov --- 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 87ab9b8f56b5..529cf36b7edb 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2783,11 +2783,13 @@ 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); } -- 2.16.1