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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 E15A0C04AB6 for ; Fri, 31 May 2019 13:13:31 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B9E94265BA for ; Fri, 31 May 2019 13:13:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B9E94265BA 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 ([127.0.0.1]:43353 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWhLe-0004X9-Uq for qemu-devel@archiver.kernel.org; Fri, 31 May 2019 09:13:30 -0400 Received: from eggs.gnu.org ([209.51.188.92]:55793) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWhK6-0003E6-2p for qemu-devel@nongnu.org; Fri, 31 May 2019 09:11:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hWh7U-0005Oe-IY for qemu-devel@nongnu.org; Fri, 31 May 2019 08:58:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1177) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hWh7U-0005Ni-Cs for qemu-devel@nongnu.org; Fri, 31 May 2019 08:58:52 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 988873092669 for ; Fri, 31 May 2019 12:58:51 +0000 (UTC) Received: from redhat.com (ovpn-116-135.ams2.redhat.com [10.36.116.135]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 03899601AC; Fri, 31 May 2019 12:58:46 +0000 (UTC) From: Juan Quintela To: Peter Xu In-Reply-To: <20190530092919.26059-3-peterx@redhat.com> (Peter Xu's message of "Thu, 30 May 2019 17:29:09 +0800") References: <20190530092919.26059-1-peterx@redhat.com> <20190530092919.26059-3-peterx@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) Date: Fri, 31 May 2019 14:58:43 +0200 Message-ID: <87imtqok58.fsf@trasno.org> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Fri, 31 May 2019 12:58:51 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v3 02/12] migration: No need to take rcu during sync_dirty_bitmap X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: quintela@redhat.com Cc: Laurent Vivier , Paolo Bonzini , qemu-devel@nongnu.org, "Dr . David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Peter Xu wrote: > cpu_physical_memory_sync_dirty_bitmap() has one RAMBlock* as > parameter, which means that it must be with RCU read lock held > already. Taking it again inside seems redundant. Removing it. > Instead comment on the functions about the RCU read lock. Anyways, hotplug/unplug is suppossed to be disable during migration. If we add/remove a ramblock during migration bad things could happen. Later, Juan.