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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 6FEDAC433E0 for ; Tue, 16 Feb 2021 08:24:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E8C364E02 for ; Tue, 16 Feb 2021 08:24:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229830AbhBPIYS (ORCPT ); Tue, 16 Feb 2021 03:24:18 -0500 Received: from mx2.suse.de ([195.135.220.15]:45514 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229811AbhBPIVv (ORCPT ); Tue, 16 Feb 2021 03:21:51 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1613463662; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=yxFwziSyZyOqU27QatYvWYrbroR4UnAqOg89qO7rMuM=; b=eYhfed6NW++hDwqLUPTACF6UbC/shda+lS/QxJlotWM16Wipv6jy5WmRh0cQc/dRvyIxn1 ej82DijW+bwiWE8xN5YuvI0cL/vh4pQBm5opBLNybn59CV64dhCAs6bX7KzaRJl7Wzoetb brEJ3VJWFdkxM425lJ/yR6eCq3l9z6o= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 8D7B1AD29; Tue, 16 Feb 2021 08:21:02 +0000 (UTC) Date: Tue, 16 Feb 2021 09:21:01 +0100 From: Michal Hocko To: David Hildenbrand Cc: Muchun Song , Jonathan Corbet , Mike Kravetz , Thomas Gleixner , mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, Peter Zijlstra , viro@zeniv.linux.org.uk, Andrew Morton , paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, Randy Dunlap , oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, Mina Almasry , David Rientjes , Matthew Wilcox , Oscar Salvador , "Song Bao Hua (Barry Song)" , HORIGUCHI =?utf-8?B?TkFPWUEo5aCA5Y+jIOebtOS5nyk=?= , Joao Martins , Xiongchun duan , linux-doc@vger.kernel.org, LKML , Linux Memory Management List , linux-fsdevel Subject: Re: [External] Re: [PATCH v15 4/8] mm: hugetlb: alloc the vmemmap pages associated with each HugeTLB page Message-ID: References: <4f8664fb-0d65-b7d6-39d6-2ce5fc86623a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4f8664fb-0d65-b7d6-39d6-2ce5fc86623a@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 16-02-21 09:13:09, David Hildenbrand wrote: > On 15.02.21 20:02, Michal Hocko wrote: > > Would it be feasible to reused parts of the freed page in > > the worst case? > > As already discussed, this is only possible when the huge page does not > reside on ZONE_MOVABLE/CMA. Right. But usually this is not the case so it would be at least something. > In addition, we can no longer form a huge page at that memory location ever. Yes, that's why I am saying in the worst case. E.g. when dissolving is really necessary like in hwpoison case. Maybe we are really far from needing something like that. I just wanted to mention this option and I was not aware this has been discussed previously. -- Michal Hocko SUSE Labs