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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 49E67C4167B for ; Mon, 4 Dec 2023 13:19:37 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rA8qf-0002rN-Po; Mon, 04 Dec 2023 08:18:57 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rA8qe-0002qh-V7 for qemu-devel@nongnu.org; Mon, 04 Dec 2023 08:18:56 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rA8qc-0007ym-5e for qemu-devel@nongnu.org; Mon, 04 Dec 2023 08:18:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701695933; 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: in-reply-to:in-reply-to:references:references; bh=VHQ4HR2B7MLC//HgFh3nAtqLerMP/Y4A9vM9X/MfQuk=; b=UaF4V0No7fy4bcb7RMdbuicrA6ZKcxjbGqQal9rokXi850dNMkeZKTGQZe9gjgq+heEYie xUZo1y1kiqscOhHUnpt6jn2JrlFuzAzn2KPgt30BdbD3yZcXPq1IGQMxR7X0d/TOubDrmE mEi/Lte4HAf9feBBmj8CyZrwZrQJiKA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-628-mkzkasI9PUCWPgI5RxpOKg-1; Mon, 04 Dec 2023 08:18:49 -0500 X-MC-Unique: mkzkasI9PUCWPgI5RxpOKg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9B9E1101A52D; Mon, 4 Dec 2023 13:18:48 +0000 (UTC) Received: from redhat.com (unknown [10.39.194.237]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B423140C6EB9; Mon, 4 Dec 2023 13:18:43 +0000 (UTC) Date: Mon, 4 Dec 2023 14:18:42 +0100 From: Kevin Wolf To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, Hanna Reitz , Paul Durrant , Paolo Bonzini , Alberto Garcia , Emanuele Giuseppe Esposito , John Snow , Eric Blake , Wen Congyang , qemu-block@nongnu.org, xen-devel@lists.xenproject.org, Coiby Xu , Eduardo Habkost , Xie Changlong , Ari Sundholm , Li Zhijian , Cleber Rosa , Juan Quintela , "Michael S. Tsirkin" , Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , Jason Wang , Vladimir Sementsov-Ogievskiy , Zhang Chen , Peter Xu , Anthony Perard , Stefano Stabellini , Leonardo Bras , Pavel Dovgalyuk , Fam Zheng , Fabiano Rosas Subject: Re: [PATCH 03/12] aio: make aio_context_acquire()/aio_context_release() a no-op Message-ID: References: <20231129195553.942921-1-stefanha@redhat.com> <20231129195553.942921-4-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231129195553.942921-4-stefanha@redhat.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 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: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 29.11.2023 um 20:55 hat Stefan Hajnoczi geschrieben: > aio_context_acquire()/aio_context_release() has been replaced by > fine-grained locking to protect state shared by multiple threads. The > AioContext lock still plays the role of balancing locking in > AIO_WAIT_WHILE() and many functions in QEMU either require that the > AioContext lock is held or not held for this reason. In other words, the > AioContext lock is purely there for consistency with itself and serves > no real purpose anymore. > > Stop actually acquiring/releasing the lock in > aio_context_acquire()/aio_context_release() so that subsequent patches > can remove callers across the codebase incrementally. > > I have performed "make check" and qemu-iotests stress tests across > x86-64, ppc64le, and aarch64 to confirm that there are no failures as a > result of eliminating the lock. > > Signed-off-by: Stefan Hajnoczi YOLO. Acked-by: Kevin Wolf