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=1.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 6EB10C3F2C6 for ; Tue, 3 Mar 2020 21:18:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 430A020848 for ; Tue, 3 Mar 2020 21:18:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583270306; bh=9nZtCyRm9ddWtpuTWo561LEWtyColZSm3B3JWQB0Fso=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=bDKQTX5jbNsGfB1ZRVod5HDSNhFg1EwQS/e2RZm1dSUSKCmlCxPSy7c9ZZVrCiBrH jE++dT8HRAYY8o7U22/+L2tZD/bJXmaVRKKpxe2Gg0C1TKTz9LOtj/uJgwTv/EkLCQ Geft89GD7HIfTLjUM8MWBYs1Je69rc6qkkVzpnJk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732515AbgCCVSY (ORCPT ); Tue, 3 Mar 2020 16:18:24 -0500 Received: from mail-pf1-f193.google.com ([209.85.210.193]:41030 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732075AbgCCVSY (ORCPT ); Tue, 3 Mar 2020 16:18:24 -0500 Received: by mail-pf1-f193.google.com with SMTP id j9so2118407pfa.8 for ; Tue, 03 Mar 2020 13:18:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=3Al6Dba4vILzb1qGfePPll7WwcKDQ0se1L1GE0jp6m8=; b=BA/d+Rs5vr4vZfcSXEN8gZw1/tyxpNLiyJnUgSQPAWrFPEnY5zoXLi8iwGcp8uPM7u byhoung4nkNM7ARSc4msBvvFfFsGgWDk6nMvvdIPvBXa5Tsbu1C1kllPumuG/t6sbiik ZUxvzUVW3fn7SGs6BmTxQYQE8KawqTY32dPx7JvbmKn7viuzwsBI2cyHeknKK6+flvki YGfueIWiFCjYK/aVodY/FLqMypenlebQk242WUQvee2Ei0pc+gWRuq37V174eFjqh+Oe PBJUXFhGKBOCSMWToWAHJJqweMRSKKypOtfdRqVJ0mObww4RLIuf039/8OTPqD0qTCi3 Iv4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=3Al6Dba4vILzb1qGfePPll7WwcKDQ0se1L1GE0jp6m8=; b=Ef+//Omw8oovR0R51T2UZBlg5Yj/oW2AAL6kFFbljJHZPk+cxxJ3/3tyWOFKQk4blS Pq63hbAM2beyZIBmfAG/M+KgjZqWl8tRej7ywgDIu7invEZ9GLAjNj5/cAefufKz2s1Y h93EJ9D8orxy8EzUxK45gdrwUyBClS/w+XwHjTP+ZEB5gFUeihPZmDFrNdtVGYzUnrJK 3d/UthN0aZsfHOcUt7xtyvnjTpi3wxmb2JdEDCtIpaDn6uvbamaINu3LR3DxF9VSKkvi oLS7x4O9qBMBZ4+fyJDbiJgJVGL59uUTr3ThsBshqvpZk8cKSi3tAaQWg93SOx3cn69N VEgQ== X-Gm-Message-State: ANhLgQ2i53AH8uJqR4YyXC43l/ebuNw9sQD3v8SMZ/c+fnw5b/hR/mI8 9FrG/n4MjV4GzNv3+hbKZ+GFAhu+ X-Google-Smtp-Source: ADFU+vutWbwjVREvrg7CwC+hKBwCnK7xhctkxH3euoL5afj5wLtv2BcaDSZsz5PXxKy/44oEMlWueg== X-Received: by 2002:a05:6a00:cb:: with SMTP id e11mr5969571pfj.88.1583270303364; Tue, 03 Mar 2020 13:18:23 -0800 (PST) Received: from google.com ([2620:15c:211:1:3e01:2939:5992:52da]) by smtp.gmail.com with ESMTPSA id d77sm12688895pfd.109.2020.03.03.13.18.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Mar 2020 13:18:21 -0800 (PST) Date: Tue, 3 Mar 2020 13:18:19 -0800 From: Minchan Kim To: Matthew Wilcox Cc: Andrew Morton , linux-mm , LKML , Jan Kara , Josef Bacik , Johannes Weiner Subject: Re: [PATCH v2] mm: fix long time stall from mm_populate Message-ID: <20200303211819.GB219683@google.com> References: <20200303002638.206421-1-minchan@kernel.org> <20200303012203.GR29971@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200303012203.GR29971@bombadil.infradead.org> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 02, 2020 at 05:22:03PM -0800, Matthew Wilcox wrote: > On Mon, Mar 02, 2020 at 04:26:38PM -0800, Minchan Kim wrote: > > @@ -1196,6 +1196,7 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors) > > struct vm_area_struct *vma = NULL; > > int locked = 0; > > long ret = 0; > > + bool tried = false; > > How about ... > > int *lockedp = &locked; > > > > > end = start + len; > > > > @@ -1226,14 +1227,18 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors) > > * double checks the vma flags, so that it won't mlock pages > > * if the vma was already munlocked. > > */ > > - ret = populate_vma_page_range(vma, nstart, nend, &locked); > > + ret = populate_vma_page_range(vma, nstart, nend, > > + tried ? NULL : &locked); > > ret = populate_vma_page_range(vma, nstart, nend, lockedp); > > > if (ret < 0) { > > if (ignore_errors) { > > ret = 0; > > continue; /* continue at next VMA */ > > } > > break; > > - } > > + } else if (ret == 0) > > + tried = true; > > + else > > + tried = false; > > } else if (ret == 0) > lockedp = NULL; > > Maybe there's a better name than lockedp. Thanks for the review, Matthew. It changes the behavior from mine in that it never set lockedp as "non-NULL" since it had retried so that we lose fault retrying optimization for successive addresses I understand the code is not pretty there so that hard to follow it but I am not sure the your suggestion makes it better.