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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 075B4C10F00 for ; Fri, 6 Mar 2020 10:22:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C7B3F2084E for ; Fri, 6 Mar 2020 10:22:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C7B3F2084E 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 5F9E06B0005; Fri, 6 Mar 2020 05:22:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5AA406B0006; Fri, 6 Mar 2020 05:22:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 498996B0007; Fri, 6 Mar 2020 05:22:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0056.hostedemail.com [216.40.44.56]) by kanga.kvack.org (Postfix) with ESMTP id 2B9636B0005 for ; Fri, 6 Mar 2020 05:22:12 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id E73CA2C0C for ; Fri, 6 Mar 2020 10:22:11 +0000 (UTC) X-FDA: 76564547262.28.leg40_131d115c7e562 X-HE-Tag: leg40_131d115c7e562 X-Filterd-Recvd-Size: 2843 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Fri, 6 Mar 2020 10:22:11 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 55E98B1D2; Fri, 6 Mar 2020 10:22:09 +0000 (UTC) Subject: Re: [PATCH v7 3/7] mm: check fatal signal pending of target process To: Minchan Kim , Andrew Morton Cc: LKML , linux-mm , linux-api@vger.kernel.org, oleksandr@redhat.com, Suren Baghdasaryan , Tim Murray , Daniel Colascione , Sandeep Patil , Sonny Rao , Brian Geffon , Michal Hocko , Johannes Weiner , Shakeel Butt , John Dias , Joel Fernandes , Jann Horn , alexander.h.duyck@linux.intel.com, sj38.park@gmail.com References: <20200302193630.68771-1-minchan@kernel.org> <20200302193630.68771-4-minchan@kernel.org> From: Vlastimil Babka Message-ID: <2f3a9530-483d-0861-3844-bc12d212dd93@suse.cz> Date: Fri, 6 Mar 2020 11:22:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200302193630.68771-4-minchan@kernel.org> Content-Type: text/plain; charset=utf-8 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 3/2/20 8:36 PM, Minchan Kim wrote: > Bail out to prevent unnecessary CPU overhead if target process has > pending fatal signal during (MADV_COLD|MADV_PAGEOUT) operation. > > Reviewed-by: Suren Baghdasaryan > Signed-off-by: Minchan Kim Reviewed-by: Vlastimil Babka Nit below: > --- > mm/madvise.c | 29 +++++++++++++++++++++-------- > 1 file changed, 21 insertions(+), 8 deletions(-) > > diff --git a/mm/madvise.c b/mm/madvise.c > index 349473fc6683..6543f2bfc3d8 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -36,6 +36,7 @@ > struct madvise_walk_private { > struct mmu_gather *tlb; > bool pageout; > + struct task_struct *target_task; > }; > > /* > @@ -316,6 +317,10 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, > if (fatal_signal_pending(current)) > return -EINTR; > > + if (private->target_task && > + fatal_signal_pending(private->target_task)) > + return -EINTR; With madvise(2) private->target_task will be current, thus current will be tested twice. Not wrong, but maybe add a "private->target_task != current" condition?