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=-5.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,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 D2977C33CA4 for ; Fri, 10 Jan 2020 13:45:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A803620842 for ; Fri, 10 Jan 2020 13:45:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=shutemov-name.20150623.gappssmtp.com header.i=@shutemov-name.20150623.gappssmtp.com header.b="pzPqUCaJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727855AbgAJNpt (ORCPT ); Fri, 10 Jan 2020 08:45:49 -0500 Received: from mail-lj1-f195.google.com ([209.85.208.195]:35110 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727445AbgAJNpt (ORCPT ); Fri, 10 Jan 2020 08:45:49 -0500 Received: by mail-lj1-f195.google.com with SMTP id j1so2211696lja.2 for ; Fri, 10 Jan 2020 05:45:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=sMdYXYMVS7cRrddfmjCZFkKAH1VKFwTqwzh9JCAXz3M=; b=pzPqUCaJLWaz/7wBdutwYJL0ZPJ655iIRXGBeBg0KwUzzokEOMPJ3KQL+uP4NRwhp4 t1EpK+CONNUtkFcnfQegpyQrffFuztUfxm8D45KcA5siHagGjRFE74tYh3V1MHszpfbo EKndhwn6cHW7xPn5mIsBZLOXZoOhVzilJWsmnQhLE+XoJHL+jol55SAdC7UnrU9OhiyT hSaoinZiRU/l6gFTPCO+wbMWkSMO/Iq5teLULZ0hqegzOyH5NDE33e+k3ETCAG669F2x +xD6WvLhxyfrqboug0IzGKUyZ94PMq2lh3l73eICULfHX+rlnjwB8k/WfjFUKp89aFfi WyHg== 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:user-agent; bh=sMdYXYMVS7cRrddfmjCZFkKAH1VKFwTqwzh9JCAXz3M=; b=X+PEkLBJR5l4e9ZXqq2TyIaOHjoUbDTiW8FOnTf0/thirtEGikfPR8vo5/ZyPq3cMx 8Qvyi7EHc2mWrjFR7+SQ8CkYbasv+L1fzKkNBHF87XedNF2rG5GESe7YGPdm6pzyJGRJ hdxE+f3PBJARnV1k83XOo763+qd2PIBCF7cj59p192+hHnI8B3AaQ134Hw0AKLPnEp1q Dlx7VqieKrSw+n/3eUjWUuZ/pYkQArkEKJmXTgbymqfEGQ2Shenq1jIWi8jP/Yq0xvvB EE3SVXuSUGPeO1Tqc+t6NLyw3VB+FbAjLcjUwdwsPU2u5/Hj4CNJsJH6rFmxjs5FkxDu xl/w== X-Gm-Message-State: APjAAAV9D9LzjFNDehkWMetiwkYiW5enwFL3b9stI4JoNrlwo7rn9RzJ 9L4G15X+eFdTt5LlgrNyXrPp+w== X-Google-Smtp-Source: APXvYqyqXd+YM/fERFV0tcUWKo1oDvb7oiPTlSCZnH/zmqCgGxZz2UoXgHoX94/CGmanCodSgLYSHA== X-Received: by 2002:a2e:9c04:: with SMTP id s4mr2779471lji.147.1578663947404; Fri, 10 Jan 2020 05:45:47 -0800 (PST) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id c189sm1062491lfg.75.2020.01.10.05.45.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Jan 2020 05:45:46 -0800 (PST) Received: by box.localdomain (Postfix, from userid 1000) id 189891010D7; Fri, 10 Jan 2020 16:45:47 +0300 (+03) Date: Fri, 10 Jan 2020 16:45:47 +0300 From: "Kirill A. Shutemov" To: David Hildenbrand Cc: Michal Hocko , Andrew Morton , Dan Williams , Vlastimil Babka , Mel Gorman , "Jin, Zhi" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: Re: [PATCH] mm/page_alloc: Skip non present sections on zone initialization Message-ID: <20200110134547.v6ju5dxazknfjdj3@box> References: <20191230093828.24613-1-kirill.shutemov@linux.intel.com> <20200108144044.GB30379@dhcp22.suse.cz> <73437651-822f-fcec-3b96-281fb1064cf8@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <73437651-822f-fcec-3b96-281fb1064cf8@redhat.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 10, 2020 at 02:15:26PM +0100, David Hildenbrand wrote: > On 08.01.20 15:40, Michal Hocko wrote: > > On Mon 30-12-19 12:38:28, Kirill A. Shutemov wrote: > >> memmap_init_zone() can be called on the ranges with holes during the > >> boot. It will skip any non-valid PFNs one-by-one. It works fine as long > >> as holes are not too big. > >> > >> But huge holes in the memory map causes a problem. It takes over 20 > >> seconds to walk 32TiB hole. x86-64 with 5-level paging allows for much > >> larger holes in the memory map which would practically hang the system. > >> > >> Deferred struct page init doesn't help here. It only works on the > >> present ranges. > >> > >> Skipping non-present sections would fix the issue. > > > > Makes sense to me. > > > >> Signed-off-by: Kirill A. Shutemov > > > > That pfn inc back and forth is quite ugly TBH but whatever. > > Indeed, can we please rewrite the loop to fix that? Any suggestions? I don't see an obvious way to not break readablity in another place. -- Kirill A. Shutemov