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 08A27C4167B for ; Mon, 4 Dec 2023 15:28:34 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rAAs1-0008TE-AN; Mon, 04 Dec 2023 10:28:29 -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 1rAAs0-0008S3-61 for qemu-devel@nongnu.org; Mon, 04 Dec 2023 10:28:28 -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 1rAAry-0006ut-7n for qemu-devel@nongnu.org; Mon, 04 Dec 2023 10:28:27 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701703705; 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=Mw1n2iwWlxYJr/7HBbY1pvYJV1N7+O+g4l43V+wCbdA=; b=P3E2VSMkpXhM/I0q3w8L0RLl149dOua8TmUCDxSqoNCy94QatNWqAa7yzGqLLi+ApDSZ9m 4/S22d/UassbhVNX98N3fasByOC7HA2S1t7PzdLH5zEcgfYs9jPomd/kuO/7+PCxpHCPqB OsPm2xBKeZUsKHIUM7fCtBZdcT/LJfM= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-352-_Yfp09vsNCuBjPIILTtLvw-1; Mon, 04 Dec 2023 10:28:23 -0500 X-MC-Unique: _Yfp09vsNCuBjPIILTtLvw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (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 84BD21C0652D; Mon, 4 Dec 2023 15:28:21 +0000 (UTC) Received: from localhost (unknown [10.39.192.49]) by smtp.corp.redhat.com (Postfix) with ESMTP id C79C3492BE0; Mon, 4 Dec 2023 15:28:19 +0000 (UTC) Date: Mon, 4 Dec 2023 10:28:17 -0500 From: Stefan Hajnoczi To: Eric Blake Cc: qemu-devel@nongnu.org, Hanna Reitz , Paul Durrant , Paolo Bonzini , Alberto Garcia , Emanuele Giuseppe Esposito , John Snow , Kevin Wolf , 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 05/12] block: remove AioContext locking Message-ID: <20231204152817.GD1492005@fedora> References: <20231129195553.942921-1-stefanha@redhat.com> <20231129195553.942921-6-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="HAuHzOT83qxPp7gF" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@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=ham 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 --HAuHzOT83qxPp7gF Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Nov 30, 2023 at 03:31:37PM -0600, Eric Blake wrote: > On Wed, Nov 29, 2023 at 02:55:46PM -0500, Stefan Hajnoczi wrote: > > This is the big patch that removes > > aio_context_acquire()/aio_context_release() from the block layer and > > affected block layer users. > >=20 > > There isn't a clean way to split this patch and the reviewers are likely > > the same group of people, so I decided to do it in one patch. > >=20 > > Signed-off-by: Stefan Hajnoczi > > --- >=20 > > +++ b/block.c > > @@ -7585,29 +7433,12 @@ void coroutine_fn bdrv_co_leave(BlockDriverStat= e *bs, AioContext *old_ctx) > > =20 > > void coroutine_fn bdrv_co_lock(BlockDriverState *bs) > > { > > - AioContext *ctx =3D bdrv_get_aio_context(bs); > > - > > - /* In the main thread, bs->aio_context won't change concurrently */ > > - assert(qemu_get_current_aio_context() =3D=3D qemu_get_aio_context(= )); > > - > > - /* > > - * We're in coroutine context, so we already hold the lock of the = main > > - * loop AioContext. Don't lock it twice to avoid deadlocks. > > - */ > > - assert(qemu_in_coroutine()); >=20 > Is this assertion worth keeping in the short term?... Probably not because coroutine vs non-coroutine functions don't change in this patch series, so it's unlikely that this will break. >=20 > > - if (ctx !=3D qemu_get_aio_context()) { > > - aio_context_acquire(ctx); > > - } > > + /* TODO removed in next patch */ > > } >=20 > ...I guess I'll see in the next patch. >=20 > > =20 > > void coroutine_fn bdrv_co_unlock(BlockDriverState *bs) > > { > > - AioContext *ctx =3D bdrv_get_aio_context(bs); > > - > > - assert(qemu_in_coroutine()); > > - if (ctx !=3D qemu_get_aio_context()) { > > - aio_context_release(ctx); > > - } > > + /* TODO removed in next patch */ > > } >=20 > Same comment. >=20 > > +++ b/blockdev.c > > @@ -1395,7 +1352,6 @@ static void external_snapshot_action(TransactionA= ction *action, > > /* File name of the new image (for 'blockdev-snapshot-sync') */ > > const char *new_image_file; > > ExternalSnapshotState *state =3D g_new0(ExternalSnapshotState, 1); > > - AioContext *aio_context; > > uint64_t perm, shared; > > =20 > > /* TODO We'll eventually have to take a writer lock in this functi= on */ >=20 > I'm guessing removal of the locking gets us one step closer to > implementing this TODO at a later time? Or is it now a stale comment? > Either way, it doesn't affect this patch. I'm not sure. Kevin can answer questions about the graph lock. > > +++ b/tests/unit/test-blockjob.c >=20 > > -static void test_complete_in_standby(void) > > -{ >=20 > > @@ -531,13 +402,5 @@ int main(int argc, char **argv) > > g_test_add_func("/blockjob/cancel/standby", test_cancel_standby); > > g_test_add_func("/blockjob/cancel/pending", test_cancel_pending); > > g_test_add_func("/blockjob/cancel/concluded", test_cancel_conclude= d); > > - > > - /* > > - * This test is flaky and sometimes fails in CI and otherwise: > > - * don't run unless user opts in via environment variable. > > - */ > > - if (getenv("QEMU_TEST_FLAKY_TESTS")) { > > - g_test_add_func("/blockjob/complete_in_standby", test_complete= _in_standby); > > - } >=20 > Looks like you ripped out this entire test, because it is no longer > viable. I might have mentioned it in the commit message, or squashed > the removal of this test into the earlier 02/12 patch. I have sent a separate patch to remove this test and once it's merged this hunk will disappear this patch series: https://lore.kernel.org/qemu-devel/20231127170210.422728-1-stefanha@redhat.= com/ Stefan --HAuHzOT83qxPp7gF Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmVt8BEACgkQnKSrs4Gr c8hIDgf5AYIr9dtEi7g5tsNLswyVkC2lDiMCBpf3ojJvX75zC6z2Y8fKDhunSi4B 7HpCHDeCFhoBFNQj7eXRbQgkdgqX7gLeBbXbwh+MT8q24VjfKHprjXuQJz4HFFNx tls/oGcNkdSoPqfkO9Paso1BNF9gl9xQIAubT7foM3O0eJ9gQk+vEiBIw5/8QykZ QKIHF6LkP6S7r7QOwhP9X4TBtudTZ9O2GIGXFdcpT9H4rYiTKSnT06NWziHZqqX6 3hViBZQI4yJySS9/wNhqX813PUjgfZAdZUGeye3eUHbdwlxNtYr6zF+4FshxfaI9 n4t6uI9nuJAyXYDz4wCBh3QI2yauuw== =/mcM -----END PGP SIGNATURE----- --HAuHzOT83qxPp7gF--