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_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 376B6C33C9E for ; Tue, 7 Jan 2020 13:36:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 001E52081E for ; Tue, 7 Jan 2020 13:36:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578404188; bh=IBTIy0if1YZO9UihklShSddP6rusTKUkvMMlAUvcBbc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ENXEsev8U81kIV9xkhGl0ukPx7utI+J/hJugA2Yy194IkWkHy/Z8CJHoosdXAMZ// m3MWkWvzx3RrqvKTD7qLypx0IPVrCJEjc7jELpjteo2dnSzRNoDFxFZ5+ihZgPfNpW jKuuyRZbTTH5LJ5bLJ3zK9gOnd8g8ssVImPFVnNQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728066AbgAGNg1 (ORCPT ); Tue, 7 Jan 2020 08:36:27 -0500 Received: from mail-wr1-f68.google.com ([209.85.221.68]:39494 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727944AbgAGNg1 (ORCPT ); Tue, 7 Jan 2020 08:36:27 -0500 Received: by mail-wr1-f68.google.com with SMTP id y11so53947646wrt.6; Tue, 07 Jan 2020 05:36:25 -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=Jvp+5VtcpYOml5Xnhk48gWmHYAeEUI3AvmIrtkYy0R1QdyM953N7vZmAZZJC5NSGyu yi8USaYbD1xM0Ql2wz6wWfiAI2C5jDcqGtIseHx1QKvB/lbZ7hfmNlN1DsPZkuaZ+O1R +VNTVLOfvtz/s6yPz9cWSNUP+Q6U6+W359kX64ACVs6x1WTkieV7Lz4NMSW7EyFL03uP RJ5RJf6JuWZyM2CekHmzrvfWl3mxg82W/aYsQBoocgmFzZnFm4JDCeUmhuEWyIqwIrDQ e21jw9srnYuvEVxZQSinWWBYUxsNozTG6Ehb+rFFmNZ+OrflljfssybxGOLPKdnNa2pR jMjw== X-Gm-Message-State: APjAAAXXgmoUJVdkv8WYW6rdnc90bEoekvcIfBi+RictlR/rJazK1zMV H0Xbqv4jN8a3Y/kcjInbBbg= 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) Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org 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