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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 E0D40C4360F for ; Tue, 26 Feb 2019 12:09:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFE46217F9 for ; Tue, 26 Feb 2019 12:09:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551182965; bh=phjMlhQFpn3LuE/36mFjR9doP93UxX1cvoVhII/S3uQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ilUcIw/CbwwuGa7hLR0NdjKbXU7lWRKWqXMYu7VQcq4n8csYoftfI6E5DQbTa98Mj XyC0LphqVO+uJwwM5Dgw0gW4sL8G5c5onjpz3v9k2/Y1kSm4pr4oDuAN1vzMcwX6gX 63ONqRZkmZApYE8wA+vFx6pNsyFoQk1AnXsRQh4Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728730AbfBZMJY (ORCPT ); Tue, 26 Feb 2019 07:09:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:34610 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726567AbfBZMJW (ORCPT ); Tue, 26 Feb 2019 07:09:22 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 2C35BB611; Tue, 26 Feb 2019 12:09:21 +0000 (UTC) Date: Tue, 26 Feb 2019 13:09:19 +0100 From: Michal Hocko To: Pingfan Liu Cc: x86@kernel.org, linux-mm@kvack.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Dave Hansen , Vlastimil Babka , Mike Rapoport , Andrew Morton , Mel Gorman , Joonsoo Kim , Andy Lutomirski , Andi Kleen , Petr Tesarik , Stephen Rothwell , Jonathan Corbet , Nicholas Piggin , Daniel Vacek , LKML Subject: Re: [PATCH 0/6] make memblock allocator utilize the node's fallback info Message-ID: <20190226120919.GY10588@dhcp22.suse.cz> References: <1551011649-30103-1-git-send-email-kernelfans@gmail.com> <20190225160358.GW10588@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 26-02-19 13:47:37, Pingfan Liu wrote: > On Tue, Feb 26, 2019 at 12:04 AM Michal Hocko wrote: > > > > On Sun 24-02-19 20:34:03, Pingfan Liu wrote: > > > There are NUMA machines with memory-less node. At present page allocator builds the > > > full fallback info by build_zonelists(). But memblock allocator does not utilize > > > this info. And for memory-less node, memblock allocator just falls back "node 0", > > > without utilizing the nearest node. Unfortunately, the percpu section is allocated > > > by memblock, which is accessed frequently after bootup. > > > > > > This series aims to improve the performance of per cpu section on memory-less node > > > by feeding node's fallback info to memblock allocator on x86, like we do for page > > > allocator. On other archs, it requires independent effort to setup node to cpumask > > > map ahead. > > > > Do you have any numbers to tell us how much does this improve the > > situation? > > Not yet. At present just based on the fact that we prefer to allocate > per cpu area on local node. Yes, we _usually_ do. But the additional complexity should be worth it. And if we find out that the final improvement is not all that great and considering that memory-less setups are crippled anyway then it might turn out we just do not care all that much. -- Michal Hocko SUSE Labs