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=-8.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 30BE3C07E96 for ; Tue, 6 Jul 2021 17:08:08 +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 F009661C4C for ; Tue, 6 Jul 2021 17:08:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F009661C4C 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]:48514 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m0oYJ-00071l-5W for qemu-devel@archiver.kernel.org; Tue, 06 Jul 2021 13:08:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34532) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m0oWz-0004qH-8E for qemu-devel@nongnu.org; Tue, 06 Jul 2021 13:06:45 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:32880) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m0oWx-0000ao-H2 for qemu-devel@nongnu.org; Tue, 06 Jul 2021 13:06:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625591203; 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=2d875CdiZ9CQ9cjGWVunbiJRwN7aSzZpFVSHPwM/rXw=; b=a6+5DjfkSW5vtde73SxRIwYQrdb3ifnUFO90Oa29+VtMmY+sCAFfTLOkzvM5vaF0eEn6J6 HFf1IJNEs2flumhm1W+08M96Cw8lMZI4nCDnIZLRpB7CO6YuQgnD9WOdbQ8T1vX4hyAiFG pmD9Luf2uoWWNiB0lBFa4Q+9gSVhFzI= 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-322-DCU4zhyZNgei5C7Hd-snLg-1; Tue, 06 Jul 2021 13:06:39 -0400 X-MC-Unique: DCU4zhyZNgei5C7Hd-snLg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AF25E804302; Tue, 6 Jul 2021 17:06:38 +0000 (UTC) Received: from redhat.com (ovpn-113-253.ams2.redhat.com [10.36.113.253]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9243D5C1D5; Tue, 6 Jul 2021 17:06:37 +0000 (UTC) Date: Tue, 6 Jul 2021 19:06:36 +0200 From: Kevin Wolf To: Max Reitz Subject: Re: [PATCH v2 0/6] block: block-status cache for data regions Message-ID: References: <20210623150143.188184-1-mreitz@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210623150143.188184-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.442, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: Vladimir Sementsov-Ogievskiy , Eric Blake , qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 23.06.2021 um 17:01 hat Max Reitz geschrieben: > Hi, > > See the cover letter from v1 for the general idea: > > https://lists.nongnu.org/archive/html/qemu-block/2021-06/msg00843.html > > > The biggest change here in v2 is that instead of having a common CoMutex > protect the block-status cache, we’re using RCU now. So to read from > the cache, or even to invalidate it, no lock is needed, only to update > it with new data. > > Disclaimer: I have no experience with RCU in practice so far, neither in > qemu nor anywhere else. So I hope I’ve used it correctly... This I hope as well. :-) With the missing qatomic_rcu_read() added: Reviewed-by: Kevin Wolf