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 CE98EC54E58 for ; Tue, 12 Mar 2024 14:46:08 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rk3OB-0006I1-VD; Tue, 12 Mar 2024 10:46:01 -0400 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 1rk3O4-000654-9C for qemu-devel@nongnu.org; Tue, 12 Mar 2024 10:45:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rk3O2-0000hm-FQ for qemu-devel@nongnu.org; Tue, 12 Mar 2024 10:45:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710254747; 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=t5VKjI+Ih/pMa8Iro8b3T5UaDs2KVMUmcZQOH9qknAM=; b=U3f9UctW8j2acoSjgsq55rX8nS2V2lR1PNorqV8LKcb8mWzI3lgvZu9FPwisNhpU8WRpES X95oPoRoJOM6r6y4+0qCvTz8EWGoSAzFAYrQyrbIZgLac5Iq3NEnGSaC2DJphXIK/p5DEn ghIWxIw8XRKeRZv+LFKqJVxCSxzzCr4= 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-423-N8-A-nxRM-yz6H-lBksJ_g-1; Tue, 12 Mar 2024 10:45:45 -0400 X-MC-Unique: N8-A-nxRM-yz6H-lBksJ_g-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (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 3075980026D; Tue, 12 Mar 2024 14:45:45 +0000 (UTC) Received: from localhost (unknown [10.39.194.198]) by smtp.corp.redhat.com (Postfix) with ESMTP id BA7523C22; Tue, 12 Mar 2024 14:45:44 +0000 (UTC) Date: Tue, 12 Mar 2024 10:45:43 -0400 From: Stefan Hajnoczi To: Prasad Pandit Cc: Kevin Wolf , qemu-block@nongnu.org, qemu-devel@nongnu.org, Prasad Pandit Subject: Re: [PATCH v2] linux-aio: add IO_CMD_FDSYNC command support Message-ID: <20240312144543.GA411413@fedora> References: <20240311054333.1264776-1-ppandit@redhat.com> <20240311130908.GA327967@fedora> <20240311193641.GA384474@fedora> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="80w70sLG3shHPf5U" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.687, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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 --80w70sLG3shHPf5U Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 12, 2024 at 07:07:04PM +0530, Prasad Pandit wrote: > Hello, >=20 > On Tue, 12 Mar 2024 at 15:15, Kevin Wolf wrote: > > Am 11.03.2024 um 20:36 hat Stefan Hajnoczi geschrieben: > > > > > That can be avoided with a variable that keeps track of whether -= EINVAL was seen before and skips Linux AIO in that > > > > > case. > > > > > > > > > > Fallback should be very rare, so I don't think it needs to be opt= imized: > > You're right. I missed that io_submit() returns failure only if the > > first request in the queue is invalid, and returns a "short submission" > > for errors in later entries. >=20 > =3D=3D=3D > +bool laio_has_fdsync(int fd) > +{ > + AioContext *ctx =3D qemu_get_current_aio_context(); > + struct qemu_laiocb cb =3D { > + .co =3D qemu_coroutine_self(), > + .ctx =3D aio_get_linux_aio(ctx), > + }; > + struct iocb *iocbs[] =3D {&cb.iocb, NULL}; > + > + /* check if host kernel supports IO_CMD_FDSYNC */ > + io_prep_fdsync(&cb.iocb, fd); > + int ret =3D io_submit(cb.ctx->ctx, 1, iocbs); > + > + return ret !=3D -EINVAL; > +} > =3D=3D=3D >=20 > To confirm: > * Do we need a revised patch V3? I'm testing one with the above > function to check if IO_CMD_FDSYNC is supported. If it returns true we > call laio_co_submit(..., QEMU_AIO_FLUSH, ), else fallback to > thread-pool. If you are already developing and testing it then I think a v3 with laio_has_fdsync() would be great. Thanks, Stefan --80w70sLG3shHPf5U Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmXwapcACgkQnKSrs4Gr c8g2GQgAwnmE7zTs5VEIM1dX+WvCblFNB4Rc+2qKgPV/lerBIwuVfO1VQSRQUmJC KlI5gKsZUafqaN5VJmDzJw9HqP6xE9xdsc4d90uiVT5LHfdC+Fdl6X4RNf3tt/VJ uBA/YdL523VUfQDjCVADDtnpNTvCbp9+Mw3fSVeX0Qb8TBXznpF1vhjykEujdKz9 RLT+ozHw52+1K+oyvAbX4phdDf5QJWpYai6f+7DFPeCRkxoF3SxH0bJ+kEzwJg3P VOpVbCvWGn9mqBgJbq7Yx16gQFft0M4afAedqLDHu/JBBAza5xXp83Ouy/9E25sj WVxWiFevAPOC6cbGOe0VObnNjxoYxg== =DT5S -----END PGP SIGNATURE----- --80w70sLG3shHPf5U--