From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34EF2C43613 for ; Mon, 24 Jun 2019 02:25:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1242220673 for ; Mon, 24 Jun 2019 02:25:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727105AbfFXCZU (ORCPT ); Sun, 23 Jun 2019 22:25:20 -0400 Received: from mga04.intel.com ([192.55.52.120]:46345 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726982AbfFXCZU (ORCPT ); Sun, 23 Jun 2019 22:25:20 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Jun 2019 19:25:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,410,1557212400"; d="scan'208";a="171832130" Received: from yhuang-dev.sh.intel.com ([10.239.159.29]) by orsmga002.jf.intel.com with ESMTP; 23 Jun 2019 19:25:17 -0700 From: "Huang, Ying" To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Ming Lei , Michal Hocko , Johannes Weiner , Hugh Dickins , Minchan Kim , Rik van Riel , Daniel Jordan Subject: [PATCH -mm] mm, swap: Fix THP swap out Date: Mon, 24 Jun 2019 10:23:36 +0800 Message-Id: <20190624022336.12465-1-ying.huang@intel.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Huang Ying 0-Day test system reported some OOM regressions for several THP (Transparent Huge Page) swap test cases. These regressions are bisected to 6861428921b5 ("block: always define BIO_MAX_PAGES as 256"). In the commit, BIO_MAX_PAGES is set to 256 even when THP swap is enabled. So the bio_alloc(gfp_flags, 512) in get_swap_bio() may fail when swapping out THP. That causes the OOM. As in the patch description of 6861428921b5 ("block: always define BIO_MAX_PAGES as 256"), THP swap should use multi-page bvec to write THP to swap space. So the issue is fixed via doing that in get_swap_bio(). BTW: I remember I have checked the THP swap code when 6861428921b5 ("block: always define BIO_MAX_PAGES as 256") was merged, and thought the THP swap code needn't to be changed. But apparently, I was wrong. I should have done this at that time. Fixes: 6861428921b5 ("block: always define BIO_MAX_PAGES as 256") Signed-off-by: "Huang, Ying" Cc: Ming Lei Cc: Michal Hocko Cc: Johannes Weiner Cc: Hugh Dickins Cc: Minchan Kim Cc: Rik van Riel Cc: Daniel Jordan --- mm/page_io.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/mm/page_io.c b/mm/page_io.c index 2e8019d0e048..4ab997f84061 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -29,10 +29,9 @@ static struct bio *get_swap_bio(gfp_t gfp_flags, struct page *page, bio_end_io_t end_io) { - int i, nr = hpage_nr_pages(page); struct bio *bio; - bio = bio_alloc(gfp_flags, nr); + bio = bio_alloc(gfp_flags, 1); if (bio) { struct block_device *bdev; @@ -41,9 +40,7 @@ static struct bio *get_swap_bio(gfp_t gfp_flags, bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9; bio->bi_end_io = end_io; - for (i = 0; i < nr; i++) - bio_add_page(bio, page + i, PAGE_SIZE, 0); - VM_BUG_ON(bio->bi_iter.bi_size != PAGE_SIZE * nr); + __bio_add_page(bio, page, PAGE_SIZE * hpage_nr_pages(page), 0); } return bio; } -- 2.20.1