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=-2.5 required=3.0 tests=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 001BAC33C8C for ; Tue, 7 Jan 2020 13:36:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BAB7F207E0 for ; Tue, 7 Jan 2020 13:36:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BAB7F207E0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5E7B38E0033; Tue, 7 Jan 2020 08:36:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 596F88E001E; Tue, 7 Jan 2020 08:36:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 45E7B8E0033; Tue, 7 Jan 2020 08:36:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0111.hostedemail.com [216.40.44.111]) by kanga.kvack.org (Postfix) with ESMTP id 2D5D28E001E for ; Tue, 7 Jan 2020 08:36:27 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id C66BD181AEF07 for ; Tue, 7 Jan 2020 13:36:26 +0000 (UTC) X-FDA: 76350937572.13.bear48_1b2015c1b5b1a X-HE-Tag: bear48_1b2015c1b5b1a X-Filterd-Recvd-Size: 3108 Received: from mail-wr1-f66.google.com (mail-wr1-f66.google.com [209.85.221.66]) by imf11.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Jan 2020 13:36:26 +0000 (UTC) Received: by mail-wr1-f66.google.com with SMTP id q6so53864635wro.9 for ; Tue, 07 Jan 2020 05:36:26 -0800 (PST) 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=AH8QrVtR12IeR8yMYo+97ujGygRwsjvu4AYsXyeVsN4=; b=ctGeuUPY6PWuSBsgD89low3IbT8GjJpJZKz7ISt/DMzKl7VFx/wCSgDDrAkCiqpjvB Y1rE38uQ5J/CB3TEDa/N12B9b8ubHLukbgxu+klpAhgjq70u2vahBPEcYeZRozxFNBX/ QFJFo1IAkt6of+NruSMLpHe6ql4EwztFtebLuqdzkXw4bSFnmAip5/7qz+p9jE9TfnFy UI3ixFvt7XhmRQ0E1pIGnovhpyjCP7L5cO0FWssSZS/2gYYOlCMsfmZKzb1445PtwrK0 n3brS9QDrdYbYmPEcWKsqWPKJ5fvKr6iLmmTfHol6VN5MN6MDz1+v7RseIBN0xA0I8+4 TqaA== X-Gm-Message-State: APjAAAXr/zcvNIOP4VPEH/1vq6LFOJkLbwWXtpF7NnIb/yC8Isznbp7K Te2f5S+1YdHZVRYBkmy8+2Q= X-Google-Smtp-Source: APXvYqySoHfDDMFqCr5GWL3JYiV6OuinzTu6RicyZZaXwH3sb5A8n5AylBh2i39PXkBOr0Awbsiv4g== X-Received: by 2002:adf:db84:: with SMTP id u4mr111448345wri.317.1578404185319; Tue, 07 Jan 2020 05:36:25 -0800 (PST) Received: from localhost (prg-ext-pat.suse.com. [213.151.95.130]) by smtp.gmail.com with ESMTPSA id f16sm76245530wrm.65.2020.01.07.05.36.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Jan 2020 05:36:24 -0800 (PST) Date: Tue, 7 Jan 2020 14:36:23 +0100 From: Michal Hocko To: lantianyu1986@gmail.com Cc: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, sashal@kernel.org, akpm@linux-foundation.org, michael.h.kelley@microsoft.com, david@redhat.com, Tianyu Lan , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, vkuznets@redhat.com, eric.devolder@oracle.com, vbabka@suse.cz, osalvador@suse.de, pavel.tatashin@microsoft.com, rppt@linux.ibm.com Subject: Re: [RFC PATCH V2 2/10] mm: expose is_mem_section_removable() symbol Message-ID: <20200107133623.GJ32178@dhcp22.suse.cz> References: <20200107130950.2983-1-Tianyu.Lan@microsoft.com> <20200107130950.2983-3-Tianyu.Lan@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200107130950.2983-3-Tianyu.Lan@microsoft.com> User-Agent: Mutt/1.12.2 (2019-09-21) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue 07-01-20 21:09:42, lantianyu1986@gmail.com wrote: > From: Tianyu Lan > > Hyper-V balloon driver will use is_mem_section_removable() to > check whether memory block is removable or not when receive > memory hot remove msg. Expose it. I do not think this is a good idea. The check is inherently racy. Why cannot the balloon driver simply hotremove the region when asked? -- Michal Hocko SUSE Labs