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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT 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 204DFC28CC0 for ; Fri, 31 May 2019 02:49:05 +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 ECAA126246 for ; Fri, 31 May 2019 02:49:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ECAA126246 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]:34430 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWXbM-0003d0-77 for qemu-devel@archiver.kernel.org; Thu, 30 May 2019 22:49:04 -0400 Received: from eggs.gnu.org ([209.51.188.92]:56063) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWXaZ-0003MP-J4 for qemu-devel@nongnu.org; Thu, 30 May 2019 22:48:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hWXaY-0006jj-Co for qemu-devel@nongnu.org; Thu, 30 May 2019 22:48:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54398) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hWXaX-0006fZ-UR for qemu-devel@nongnu.org; Thu, 30 May 2019 22:48:14 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 0F9A8308FBA6 for ; Fri, 31 May 2019 02:48:13 +0000 (UTC) Received: from xz-x1 (dhcp-15-205.nay.redhat.com [10.66.15.205]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3C3B0608CA; Fri, 31 May 2019 02:48:10 +0000 (UTC) Date: Fri, 31 May 2019 10:48:08 +0800 From: Peter Xu To: "Dr. David Alan Gilbert" Message-ID: <20190531024808.GJ28587@xz-x1> References: <20190530092919.26059-1-peterx@redhat.com> <20190530092919.26059-11-peterx@redhat.com> <20190530164037.GH2823@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190530164037.GH2823@work-vm> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Fri, 31 May 2019 02:48:13 +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 10/12] kvm: Introduce slots lock for memory listener 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: , Cc: Laurent Vivier , Paolo Bonzini , qemu-devel@nongnu.org, Juan Quintela Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, May 30, 2019 at 05:40:38PM +0100, Dr. David Alan Gilbert wrote: > * Peter Xu (peterx@redhat.com) wrote: > > Introduce KVMMemoryListener.slots_lock to protect the slots inside the > > kvm memory listener. Currently it is close to useless because all the > > KVM code path now is always protected by the BQL. But it'll start to > > make sense in follow up patches where we might do remote dirty bitmap > > clear and also we'll update the per-slot cached dirty bitmap even > > without the BQL. So let's prepare for it. > > > > We can also use per-slot lock for above reason but it seems to be an > > overkill. Let's just use this bigger one (which covers all the slots > > of a single address space) but anyway this lock is still much smaller > > than the BQL. > > > > Signed-off-by: Peter Xu > > No one ever frees it? Huh OK, in that case if no one ever frees the > listener then I guess you don't need to cleanup the lock. Yeh not the first time I see something keeps forever in QEMU (in most cases which won't hurt :). I'll just leave it to the patch where all things are cleaned up. > Reviewed-by: Dr. David Alan Gilbert Thanks, -- Peter Xu