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=-10.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 EF16FC433E0 for ; Thu, 11 Mar 2021 21:51:32 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 196B964E55 for ; Thu, 11 Mar 2021 21:51:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 196B964E55 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:53912 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lKTDP-0002cx-1L for qemu-devel@archiver.kernel.org; Thu, 11 Mar 2021 16:51:31 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:55172) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lKTC6-0001Jv-60 for qemu-devel@nongnu.org; Thu, 11 Mar 2021 16:50:10 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:34835) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lKTC4-0007OR-0w for qemu-devel@nongnu.org; Thu, 11 Mar 2021 16:50:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615499405; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=av6GL7plIQqVBmkecT2IcusHP8f0jgwys+zzL6x1jUo=; b=VjedTe+5qvtXvl9WEJy4Dn6xSonRoW6PiLhsUSDhDVmcBgKXQ95pmsJNebGwnatZrkP5JL AsoE6T/sCwMUC92NbEb+6z8tXkRdwG8BAqXkXMXOUgGUZfrs5eHOVMs6vIDEbCU0xcUTtA AZ3QrcfqFZETUttNEhd7rYqvqs+MVVA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-53-t606DMFfPSewLeuBx3YOjw-1; Thu, 11 Mar 2021 16:50:04 -0500 X-MC-Unique: t606DMFfPSewLeuBx3YOjw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9E704100C662; Thu, 11 Mar 2021 21:50:02 +0000 (UTC) Received: from [10.36.115.26] (ovpn-115-26.ams2.redhat.com [10.36.115.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id 895DD60853; Thu, 11 Mar 2021 21:49:47 +0000 (UTC) Subject: Re: [PATCH v3 02/12] softmmu/physmem: Fix ram_block_discard_range() to handle shared anonymous memory To: Peter Xu References: <20210308150600.14440-1-david@redhat.com> <20210308150600.14440-3-david@redhat.com> <20210311213756.GL194839@xz-x1> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <3bc7c6e6-88d6-907b-2ae3-bd333cccc917@redhat.com> Date: Thu, 11 Mar 2021 22:49:46 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210311213756.GL194839@xz-x1> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.25, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marcel Apfelbaum , Cornelia Huck , Eduardo Habkost , "Michael S. Tsirkin" , Stefan Weil , Murilo Opsfelder Araujo , Richard Henderson , "Dr. David Alan Gilbert" , Juan Quintela , qemu-devel@nongnu.org, Halil Pasic , Christian Borntraeger , Greg Kurz , Stefan Hajnoczi , Igor Mammedov , Thomas Huth , Paolo Bonzini , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , Igor Kotrasinski Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 11.03.21 22:37, Peter Xu wrote: > On Mon, Mar 08, 2021 at 04:05:50PM +0100, David Hildenbrand wrote: >> We can create shared anonymous memory via >> "-object memory-backend-ram,share=on,..." >> which is, for example, required by PVRDMA for mremap() to work. >> >> Shared anonymous memory is weird, though. Instead of MADV_DONTNEED, we >> have to use MADV_REMOVE. MADV_DONTNEED fails silently and does nothing. >> >> Fixes: 06329ccecfa0 ("mem: add share parameter to memory-backend-ram") > > I'm thinking whether we should keep this fixes - it's valid, however it could > unveil issues if those remapped ranges didn't get unmapped in time. After all > "not releasing some memory existed" seems not a huge deal for stable. No > strong opinion, just raise it up as a pure question. > If someone would be using it along with postcopy (which should work apart from that issue) you could be in trouble. That's why i think at least the Fixes: tag is valid. CC: stable might be debatable indeed. >> Signed-off-by: David Hildenbrand > > Reviewed-by: Peter Xu > Thanks! -- Thanks, David / dhildenb