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.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 20F85C4167B for ; Mon, 4 Dec 2023 13:19:05 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.646930.1009602 (Exim 4.92) (envelope-from ) id 1rA8qe-0000Bo-Co; Mon, 04 Dec 2023 13:18:56 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 646930.1009602; Mon, 04 Dec 2023 13:18:56 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rA8qe-0000Bh-AF; Mon, 04 Dec 2023 13:18:56 +0000 Received: by outflank-mailman (input) for mailman id 646930; Mon, 04 Dec 2023 13:18:55 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rA8qd-0000BZ-9j for xen-devel@lists.xenproject.org; Mon, 04 Dec 2023 13:18:55 +0000 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id ab9135d2-92a7-11ee-98e5-6d05b1d4d9a1; Mon, 04 Dec 2023 14:18:54 +0100 (CET) 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 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) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: ab9135d2-92a7-11ee-98e5-6d05b1d4d9a1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701695932; 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=Y/yT/TrpLB5Gj9E15XhysxQkcjQEqu390dVfNjgfuiQY1BxT+pk16SpTDI8m4Wb8rqEYY0 pcL4gi3/mFgjm4aMYomwRYeO7A32+A7FETXcSFCl8oOVWD0+shDZwThZglxzdOBGtNuqdP FSitNfdh0W3hiy0q7nhV1VRH73lvN6o= X-MC-Unique: mkzkasI9PUCWPgI5RxpOKg-1 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 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