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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82CE4C433F5 for ; Mon, 11 Oct 2021 11:12:56 +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 290C960EFE for ; Mon, 11 Oct 2021 11:12:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 290C960EFE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:33636 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mZtEj-0001nK-IZ for qemu-devel@archiver.kernel.org; Mon, 11 Oct 2021 07:12:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53356) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mZtCV-0008Fy-7o for qemu-devel@nongnu.org; Mon, 11 Oct 2021 07:10:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:27768) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mZtCR-0007hB-KP for qemu-devel@nongnu.org; Mon, 11 Oct 2021 07:10:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633950630; 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=sFZlcV+c3vnePYS4ANGNK8XN5Lx4T6xplkM754Xt+2E=; b=QyURNC55da36EzyTSnn6LV9MmMDRPaZRK9nBvhSRL0yS6W5Sqc/HQr+y5T3cm4ueTzvfWa SagtAVDpX+C2KcD9SrKaeIo/ugzwKHATgxU+/+sjqCSyKkadMV528cZyU+Z1fmKzXm9r2i 8IW0BK46Bnd3/S/pUMrek0DXar98w6Q= 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-479-g2XxsJAMN-aSW4otwYSk6g-1; Mon, 11 Oct 2021 07:10:27 -0400 X-MC-Unique: g2XxsJAMN-aSW4otwYSk6g-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id ED33F835DE6; Mon, 11 Oct 2021 11:10:25 +0000 (UTC) Received: from localhost (unknown [10.39.194.224]) by smtp.corp.redhat.com (Postfix) with ESMTP id 69B9B26E4C; Mon, 11 Oct 2021 11:10:12 +0000 (UTC) Date: Mon, 11 Oct 2021 12:10:11 +0100 From: Stefan Hajnoczi To: Emanuele Giuseppe Esposito Subject: Re: [RFC PATCH v2 11/25] include/block/blockjob.h: global state API Message-ID: References: <20211005143215.29500-1-eesposit@redhat.com> <20211005143215.29500-12-eesposit@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="B8toEKuAEPDI+uyj" Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.049, 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_H2=-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: Kevin Wolf , Fam Zheng , Vladimir Sementsov-Ogievskiy , Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , Eduardo Habkost , qemu-block@nongnu.org, Juan Quintela , qemu-devel@nongnu.org, John Snow , Richard Henderson , Markus Armbruster , "Dr. David Alan Gilbert" , Hanna Reitz , Paolo Bonzini , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --B8toEKuAEPDI+uyj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Oct 08, 2021 at 09:20:35AM +0200, Emanuele Giuseppe Esposito wrote: >=20 > > > +/* > > > + * Global state (GS) API. These functions run under the BQL lock. > > > + * > > > + * If a function modifies the graph, it also uses drain and/or > > > + * aio_context_acquire/release to be sure it has unique access. > > > + * aio_context locking is needed together with BQL because of > > > + * the thread-safe I/O API that concurrently runs and accesses > > > + * the graph without the BQL. > > > + * > > > + * It is important to note that not all of these functions are > > > + * necessarily limited to running under the BQL, but they would > > > + * require additional auditing and may small thread-safety changes > > > + * to move them into the I/O API. Often it's not worth doing that > > > + * work since the APIs are only used with the BQL held at the > > > + * moment, so they have been placed in the GS API (for now). > > > + * > > > + * All functions below must use this assertion: > > > + * g_assert(qemu_in_main_thread()); > > > + * to catch when they are accidentally called without the BQL. > > > + */ > >=20 > > This is comment is duplicated in many places. I suggest explaining it i= n > > one place and using references in the other files: > >=20 > > /* > > * Global state (GS) API. These functions run under the BQL lock. > > * > > * See include/block/block.h for more information about the GS API. > > */ > >=20 >=20 > Good idea. Should I also do that for I/O, or it's not worth for very few > lines? Up to you, but I think it makes sense to have a minimal comment for both the GS and I/O API. Stefan --B8toEKuAEPDI+uyj Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmFkG5MACgkQnKSrs4Gr c8hjTAgAgwouBjGbMWjXjMKV/xr1QnrpIhODVhIcZNFAKg6RtA5n1w85K6BUhcze mcCkwdtGaI66fmi0AvYcQLps7GlL4CeH4RL4Jg52feSG5h0YXqI6covHMV45coQT r6WIkQj8MTxdEu1yOSKNOUgkPkkxCyIkuUUzIqAQUX+c2wZzzf+SEfn4ycfszFid oFplS2pZbzS35GttC9A/RlrzmT43TlY9aweQ6V+auMyBKZZYYMKpoQ2t1MZ8ValD O4wqyxOMvYkdkhkVelQtrYd+GbkmTl56A0XVHy/j65ghgqChv5d1o5SRQWXmzmBI 2yalcPzNEGnBa6JoKxXn6kmoNu4UUg== =wGpc -----END PGP SIGNATURE----- --B8toEKuAEPDI+uyj--