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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 4858BC433E5 for ; Fri, 24 Jul 2020 14:26:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A5B420674 for ; Fri, 24 Jul 2020 14:26:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595600795; bh=uNttITY7WTd1nnCS2N479l3+BvQyW9XPrg2xcgP0Ts0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=eCCUK5Au5SfyzOL8v7aSEjR9ra4tAj4psYLnnJ7jSb4pvLg6n+2rzd+zVeNIT485g 6kXMKnO9hw+skqR0bLua26MQRqI9O8XofneKnZZeX5sJuFp9K+ZfbrWgmLNu6rer0p WUAB3NitOtSutFMGoBwe0J06UZxJJ0SGuk5LDMGQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726747AbgGXO0d (ORCPT ); Fri, 24 Jul 2020 10:26:33 -0400 Received: from mail-ed1-f66.google.com ([209.85.208.66]:40814 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726366AbgGXO0d (ORCPT ); Fri, 24 Jul 2020 10:26:33 -0400 Received: by mail-ed1-f66.google.com with SMTP id b13so4786363edz.7 for ; Fri, 24 Jul 2020 07:26:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=fQc6a55htIZJuQwps2J4GcOYjRoEwiPLJFT6XTUnmHQ=; b=co13hGAxWKrQHH7wAK1ndTvQSGgqnOVIK0/x30TQ7T9VU9aT1nbq9JUzTDjgora2nk y0V5sm10lSSM5Cvur+s190t4ww8oU/3fC+EP3+Yy5Bw2obz8bcT6cV/yEzeGS11VUOAH ljMLpdnvqq184n2aVaUHa2lAnkB548k5W7ZTBCAWMze9sXhyc4CgU7aiIdE7of1EKrsU U8lVsAWLQl/x+Kp1cRIMtvafoFA6R5xvg7rLxxTCD30cIMgkGY+S7RPhSuCFxjAV8Wll 4IurgZT8jrpecS0yvI3X3E5b3dear8lqv5Le4IUBSCcszzjV2zhQexxvi3C8bUzBPeQn 6azA== X-Gm-Message-State: AOAM5301OvudP+ZBcf5olwp4IMGRr9WTqQqlmeVIzPvQwoKFqhdm6GhH Z6JoCqbUkq1vXXAw2MJ2SzY= X-Google-Smtp-Source: ABdhPJxT/FT7VCkOSUSQBSY40kqmPgw0t7WYcwoSmE1x+0nvVqgkavSXxCfqTks2iqxN2EDg6+Xfbw== X-Received: by 2002:a05:6402:b99:: with SMTP id cf25mr8889248edb.291.1595600791843; Fri, 24 Jul 2020 07:26:31 -0700 (PDT) Received: from localhost (ip-37-188-169-187.eurotel.cz. [37.188.169.187]) by smtp.gmail.com with ESMTPSA id v24sm789166eds.71.2020.07.24.07.26.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Jul 2020 07:26:30 -0700 (PDT) Date: Fri, 24 Jul 2020 16:26:29 +0200 From: Michal Hocko To: Muchun Song Cc: mike.kravetz@oracle.com, Andrew Morton , David Rientjes , mgorman@suse.de, walken@google.com, Linux Memory Management List , LKML , Jianchao Guo Subject: Re: [Phishing Risk] [External] Re: [PATCH v2] mm/hugetlb: add mempolicy check in the reservation routine Message-ID: <20200724142629.GA31772@dhcp22.suse.cz> References: <20200724100306.33457-1-songmuchun@bytedance.com> <20200724113415.GG4061@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 24-07-20 21:56:29, Muchun Song wrote: > On Fri, Jul 24, 2020 at 7:34 PM Michal Hocko wrote: [...] > > I believe you can simplify this and use a similar pattern as the page > > allocator. Something like > > > > for_each_node_mask(node, mpol_allowed) { > > if (node_isset(node, &cpuset_current_mems_allowed)) > > nr += array[node]; > > } > > > > There shouldn't be any need to allocate a potentially large nodemask on > > the stack. > > An unsigned long can satisfy 64 nodes. So I think that nodemask is using > little stack memory. Right? CONFIG_NODES_SHIFT=10 is not something surprising. E.g. SLES is using that default for a long time because those kernels tend to run on very large machines. -- Michal Hocko SUSE Labs