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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B55AC433EF for ; Mon, 11 Apr 2022 14:11:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F12A76B0072; Mon, 11 Apr 2022 10:11:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EE7B56B0074; Mon, 11 Apr 2022 10:11:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DD8C86B0075; Mon, 11 Apr 2022 10:11:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0190.hostedemail.com [216.40.44.190]) by kanga.kvack.org (Postfix) with ESMTP id D0CF36B0072 for ; Mon, 11 Apr 2022 10:11:08 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 9038F183A352A for ; Mon, 11 Apr 2022 14:11:08 +0000 (UTC) X-FDA: 79344785016.31.D7A63F2 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf31.hostedemail.com (Postfix) with ESMTP id 3A50720002 for ; Mon, 11 Apr 2022 14:11:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=nzg4iE1+vDnobxL+x/8BGospZE26iFX69h+xdGnSEJQ=; b=DaawSJGn0Xk4L9uUaRoIE2f2Ed kYFvwL2L61aKJblxMt6UbsV/mr9PdaRqA2kABIayXFjk+qb5OxxLWndAtd7vRxR8/hn9T51yHnL2P N7F+UGOjY7P7WnY3Sja164ZbV5JuB5mr11vexOz0EUvwLyzXAhZj7IxpRzp3Ds+IQ+wdtzCCFStb3 RhDm8AczOzESjdEQ2MzljewU76Hgz+wFYcF0Ncrc9G8vi020Ro34/UBDG2U0jaAkJIIIVzCOZ6NZL 3LhH5+Ounv1yTOvJhxJtzItzgcYS+QE2ZvCqJSc1IlKqiQEcf8LpkqEZG/xnrpyn0FHAvaOaYeLL/ iAqRxzlA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1ndukk-009JZ3-EY; Mon, 11 Apr 2022 14:10:50 +0000 Date: Mon, 11 Apr 2022 07:10:50 -0700 From: Christoph Hellwig To: Miaohe Lin Cc: akpm@linux-foundation.org, mike.kravetz@oracle.com, shy828301@gmail.com, willy@infradead.org, ying.huang@intel.com, ziy@nvidia.com, minchan@kernel.org, apopple@nvidia.com, dave.hansen@linux.intel.com, o451686892@gmail.com, jhubbard@nvidia.com, peterx@redhat.com, naoya.horiguchi@nec.com, mhocko@suse.com, riel@redhat.com, osalvador@suse.de, david@redhat.com, sfr@canb.auug.org.au, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] mm/migration: return errno when isolate_huge_page failed Message-ID: References: <20220409073846.22286-1-linmiaohe@huawei.com> <20220409073846.22286-4-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220409073846.22286-4-linmiaohe@huawei.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 3A50720002 X-Stat-Signature: cjqsh5m8h1i7c79ufjf6wj7mxfk8479j X-Rspam-User: Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=DaawSJGn; dmarc=none; spf=none (imf31.hostedemail.com: domain of BATV+28f505242231dd703457+6805+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+28f505242231dd703457+6805+infradead.org+hch@bombadil.srs.infradead.org X-HE-Tag: 1649686268-749077 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Apr 09, 2022 at 03:38:45PM +0800, Miaohe Lin wrote: > We might fail to isolate huge page due to e.g. the page is under migration > which cleared HPageMigratable. So we should return -EBUSY in this case > rather than always return 1 which could confuse the user. > > Fixes: e8db67eb0ded ("mm: migrate: move_pages() supports thp migration") > Reviewed-by: Muchun Song > Reviewed-by: Baolin Wang > Signed-off-by: Miaohe Lin > --- > mm/migrate.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 381963231a62..044656a14ae2 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1632,10 +1632,8 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, > goto out_putpage; > > if (PageHuge(page)) { > - if (PageHead(page)) { > - isolate_huge_page(page, pagelist); > - err = 1; > - } > + if (PageHead(page)) > + err = isolate_huge_page(page, pagelist) ? 1 : -EBUSY; I think a: err = isolate_huge_page(page, pagelist); if (!err) err = 1; would be a lot more readable here.