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=-8.2 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_MUTT 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 947D2C43613 for ; Mon, 24 Jun 2019 09:04:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D8072083D for ; Mon, 24 Jun 2019 09:04:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728237AbfFXJEk (ORCPT ); Mon, 24 Jun 2019 05:04:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38975 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725916AbfFXJEj (ORCPT ); Mon, 24 Jun 2019 05:04:39 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4EA8C13A4D; Mon, 24 Jun 2019 09:04:39 +0000 (UTC) Received: from ming.t460p (ovpn-8-18.pek2.redhat.com [10.72.8.18]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B2AF919728; Mon, 24 Jun 2019 09:04:26 +0000 (UTC) Date: Mon, 24 Jun 2019 17:04:21 +0800 From: Ming Lei To: "Huang, Ying" Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko , Johannes Weiner , Hugh Dickins , Minchan Kim , Rik van Riel , Daniel Jordan Subject: Re: [PATCH -mm -V2] mm, swap: Fix THP swap out Message-ID: <20190624090420.GD10941@ming.t460p> References: <20190624075515.31040-1-ying.huang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190624075515.31040-1-ying.huang@intel.com> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Mon, 24 Jun 2019 09:04:39 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 24, 2019 at 03:55:15PM +0800, Huang, Ying wrote: > 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 > > Changelogs: > > V2: > > - Replace __bio_add_page() with bio_add_page() per Ming's comments. > > --- > 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..189415852077 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 > Looks fine: Reviewed-by: Ming Lei Thanks, Ming