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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 BDA03C56201 for ; Wed, 25 Nov 2020 16:26:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 213E521534 for ; Wed, 25 Nov 2020 16:26:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 213E521534 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6AACB6B005C; Wed, 25 Nov 2020 11:26:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 65B136B0070; Wed, 25 Nov 2020 11:26:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 54A456B0072; Wed, 25 Nov 2020 11:26:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0237.hostedemail.com [216.40.44.237]) by kanga.kvack.org (Postfix) with ESMTP id 3BE516B005C for ; Wed, 25 Nov 2020 11:26:51 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0819B180AD801 for ; Wed, 25 Nov 2020 16:26:51 +0000 (UTC) X-FDA: 77523469422.16.pest81_0203aef27378 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id D5695100E6903 for ; Wed, 25 Nov 2020 16:26:50 +0000 (UTC) X-HE-Tag: pest81_0203aef27378 X-Filterd-Recvd-Size: 3392 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Wed, 25 Nov 2020 16:26:50 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id F105BABCE; Wed, 25 Nov 2020 16:26:48 +0000 (UTC) Subject: Re: [PATCH v5 1/4] mm,hwpoison: drain pcplists before bailing out for non-buddy zero-refcount page To: Oscar Salvador , n-horiguchi@ah.jp.nec.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Naoya Horiguchi References: <20201013144447.6706-1-osalvador@suse.de> <20201013144447.6706-2-osalvador@suse.de> From: Vlastimil Babka Message-ID: <1673f0cd-c943-c211-4707-410c5f018aab@suse.cz> Date: Wed, 25 Nov 2020 17:26:47 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20201013144447.6706-2-osalvador@suse.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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 10/13/20 4:44 PM, Oscar Salvador wrote: > A page with 0-refcount and !PageBuddy could perfectly be a pcppage. > Currently, we bail out with an error if we encounter such a page, meaning > that we do not handle pcppages neither from hard-offline nor from > soft-offline path. > > Fix this by draining pcplists whenever we find this kind of page and retry > the check again. It might be that pcplists have been spilled into the > buddy allocator and so we can handle it. > > Signed-off-by: Oscar Salvador > Acked-by: Naoya Horiguchi Acked-by: Vlastimil Babka > --- > mm/memory-failure.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index c0bb186bba62..e2f12410c594 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -946,13 +946,13 @@ static int page_action(struct page_state *ps, struct page *p, > } > > /** > - * get_hwpoison_page() - Get refcount for memory error handling: > + * __get_hwpoison_page() - Get refcount for memory error handling: > * @page: raw error page (hit by memory error) > * > * Return: return 0 if failed to grab the refcount, otherwise true (some > * non-zero value.) > */ > -static int get_hwpoison_page(struct page *page) > +static int __get_hwpoison_page(struct page *page) > { > struct page *head = compound_head(page); > > @@ -982,6 +982,26 @@ static int get_hwpoison_page(struct page *page) > return 0; > } > > +static int get_hwpoison_page(struct page *p) > +{ > + int ret; > + bool drained = false; > + > +retry: > + ret = __get_hwpoison_page(p); > + if (!ret && !is_free_buddy_page(p) && !page_count(p) && !drained) { > + /* > + * The page might be in a pcplist, so try to drain those > + * and see if we are lucky. > + */ > + drain_all_pages(page_zone(p)); > + drained = true; > + goto retry; > + } > + > + return ret; > +} > + > /* > * Do all that is necessary to remove user space mappings. Unmap > * the pages and send SIGBUS to the processes if the data was dirty. >