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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 832E9C28EBD for ; Fri, 7 Jun 2019 02:55:10 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.47]) (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 581CE206DF for ; Fri, 7 Jun 2019 02:55:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 581CE206DF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45650 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hZ525-0005I8-HD for qemu-devel@archiver.kernel.org; Thu, 06 Jun 2019 22:55:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50963) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hZ514-0004aJ-FP for qemu-devel@nongnu.org; Thu, 06 Jun 2019 22:54:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hZ513-0006Cb-CA for qemu-devel@nongnu.org; Thu, 06 Jun 2019 22:54:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46068) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hZ4w5-0007yF-6V; Thu, 06 Jun 2019 22:48:57 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 882A33082200; Fri, 7 Jun 2019 02:48:54 +0000 (UTC) Received: from [10.3.116.85] (ovpn-116-85.phx2.redhat.com [10.3.116.85]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1B5448BE58; Fri, 7 Jun 2019 02:48:48 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, qemu-block@nongnu.org References: <20190411172709.205032-1-vsementsov@virtuozzo.com> <20190411172709.205032-6-vsementsov@virtuozzo.com> From: Eric Blake Openpgp: preference=signencrypt Autocrypt: addr=eblake@redhat.com; keydata= xsBNBEvHyWwBCACw7DwsQIh0kAbUXyqhfiKAKOTVu6OiMGffw2w90Ggrp4bdVKmCaEXlrVLU xphBM8mb+wsFkU+pq9YR621WXo9REYVIl0FxKeQo9dyQBZ/XvmUMka4NOmHtFg74nvkpJFCD TUNzmqfcjdKhfFV0d7P/ixKQeZr2WP1xMcjmAQY5YvQ2lUoHP43m8TtpB1LkjyYBCodd+LkV GmCx2Bop1LSblbvbrOm2bKpZdBPjncRNob73eTpIXEutvEaHH72LzpzksfcKM+M18cyRH+nP sAd98xIbVjm3Jm4k4d5oQyE2HwOur+trk2EcxTgdp17QapuWPwMfhaNq3runaX7x34zhABEB AAHNHkVyaWMgQmxha2UgPGVibGFrZUByZWRoYXQuY29tPsLAegQTAQgAJAIbAwULCQgHAwUV CgkICwUWAgMBAAIeAQIXgAUCS8fL9QIZAQAKCRCnoWtKJSdDahBHCACbl/5FGkUqJ89GAjeX RjpAeJtdKhujir0iS4CMSIng7fCiGZ0fNJCpL5RpViSo03Q7l37ss+No+dJI8KtAp6ID+PMz wTJe5Egtv/KGUKSDvOLYJ9WIIbftEObekP+GBpWP2+KbpADsc7EsNd70sYxExD3liwVJYqLc Rw7so1PEIFp+Ni9A1DrBR5NaJBnno2PHzHPTS9nmZVYm/4I32qkLXOcdX0XElO8VPDoVobG6 gELf4v/vIImdmxLh/w5WctUpBhWWIfQDvSOW2VZDOihm7pzhQodr3QP/GDLfpK6wI7exeu3P pfPtqwa06s1pae3ad13mZGzkBdNKs1HEm8x6zsBNBEvHyWwBCADGkMFzFjmmyqAEn5D+Mt4P zPdO8NatsDw8Qit3Rmzu+kUygxyYbz52ZO40WUu7EgQ5kDTOeRPnTOd7awWDQcl1gGBXgrkR pAlQ0l0ReO57Q0eglFydLMi5bkwYhfY+TwDPMh3aOP5qBXkm4qIYSsxb8A+i00P72AqFb9Q7 3weG/flxSPApLYQE5qWGSXjOkXJv42NGS6o6gd4RmD6Ap5e8ACo1lSMPfTpGzXlt4aRkBfvb NCfNsQikLZzFYDLbQgKBA33BDeV6vNJ9Cj0SgEGOkYyed4I6AbU0kIy1hHAm1r6+sAnEdIKj cHi3xWH/UPrZW5flM8Kqo14OTDkI9EtlABEBAAHCwF8EGAEIAAkFAkvHyWwCGwwACgkQp6Fr SiUnQ2q03wgAmRFGDeXzc58NX0NrDijUu0zx3Lns/qZ9VrkSWbNZBFjpWKaeL1fdVeE4TDGm I5mRRIsStjQzc2R9b+2VBUhlAqY1nAiBDv0Qnt+9cLiuEICeUwlyl42YdwpmY0ELcy5+u6wz mK/jxrYOpzXKDwLq5k4X+hmGuSNWWAN3gHiJqmJZPkhFPUIozZUCeEc76pS/IUN72NfprZmF Dp6/QDjDFtfS39bHSWXKVZUbqaMPqlj/z6Ugk027/3GUjHHr8WkeL1ezWepYDY7WSoXwfoAL 2UXYsMAr/uUncSKlfjvArhsej0S4zbqim2ZY6S8aRWw94J3bSvJR+Nwbs34GPTD4Pg== Organization: Red Hat, Inc. Message-ID: <834d25f9-23c9-287c-0599-905a7669a6c5@redhat.com> Date: Thu, 6 Jun 2019 21:48:47 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190411172709.205032-6-vsementsov@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="2U6CC7xS62OVCcNoU9QxIrucDq4bDmSOK" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Fri, 07 Jun 2019 02:48:54 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v6 5/7] qemu-coroutine-sleep: introduce qemu_co_sleep_wake 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: kwolf@redhat.com, den@openvz.org, armbru@redhat.com, stefanha@redhat.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --2U6CC7xS62OVCcNoU9QxIrucDq4bDmSOK Content-Type: multipart/mixed; boundary="u3DzIyC2y4l9f20KSbx9jdWvT8BfqVwUw"; protected-headers="v1" From: Eric Blake To: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: armbru@redhat.com, stefanha@redhat.com, mreitz@redhat.com, kwolf@redhat.com, den@openvz.org Message-ID: <834d25f9-23c9-287c-0599-905a7669a6c5@redhat.com> Subject: Re: [PATCH v6 5/7] qemu-coroutine-sleep: introduce qemu_co_sleep_wake References: <20190411172709.205032-1-vsementsov@virtuozzo.com> <20190411172709.205032-6-vsementsov@virtuozzo.com> In-Reply-To: <20190411172709.205032-6-vsementsov@virtuozzo.com> --u3DzIyC2y4l9f20KSbx9jdWvT8BfqVwUw Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 4/11/19 12:27 PM, Vladimir Sementsov-Ogievskiy wrote: > Introduce a function to gracefully wake-up a coroutine, sleeping in > qemu_co_sleep_ns() sleep. Maybe: Introduce a function to gracefully short-circuit the remainder of the delay for a coroutine sleeping in qemu_co_sleep_ns(). >=20 > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > include/qemu/coroutine.h | 6 ++++++ > util/qemu-coroutine-sleep.c | 20 ++++++++++++++++---- > 2 files changed, 22 insertions(+), 4 deletions(-) >=20 > diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h > index 9801e7f5a4..ec765c26f0 100644 > --- a/include/qemu/coroutine.h > +++ b/include/qemu/coroutine.h > @@ -278,6 +278,12 @@ void qemu_co_rwlock_unlock(CoRwlock *lock); > */ > void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns); > =20 > +/* > + * Wake a coroutine if it is sleeping by qemu_co_sleep_ns. Timer will = be > + * deleted. Maybe: Wake a coroutine if it is sleeping in qemu_co_sleep_ns, and delete the timer. > +++ b/util/qemu-coroutine-sleep.c > @@ -17,13 +17,24 @@ > #include "qemu/timer.h" > #include "block/aio.h" > =20 > +const char *qemu_co_sleep_ns__scheduled =3D "qemu_co_sleep_ns"; > + > +void qemu_co_sleep_wake(Coroutine *co) > +{ > + /* Write of schedule protected by barrier write in aio_co_schedule= */ > + const char *scheduled =3D atomic_cmpxchg(&co->scheduled, > + qemu_co_sleep_ns__scheduled= , NULL); > + > + if (scheduled =3D=3D qemu_co_sleep_ns__scheduled) { > + aio_co_wake(co); > + } > +} > + > static void co_sleep_cb(void *opaque) > { > Coroutine *co =3D opaque; > =20 > - /* Write of schedule protected by barrier write in aio_co_schedule= */ > - atomic_set(&co->scheduled, NULL); > - aio_co_wake(co); > + qemu_co_sleep_wake(co); > } > =20 > void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns) > @@ -32,7 +43,8 @@ void coroutine_fn qemu_co_sleep_ns(QEMUClockType type= , int64_t ns) > QEMUTimer *ts; > Coroutine *co =3D qemu_coroutine_self(); > =20 > - const char *scheduled =3D atomic_cmpxchg(&co->scheduled, NULL, __f= unc__); > + const char *scheduled =3D atomic_cmpxchg(&co->scheduled, NULL, > + qemu_co_sleep_ns__scheduled= ); > if (scheduled) { > fprintf(stderr, > "%s: Co-routine was already scheduled in '%s'\n", >=20 Here, I'd rather get an additional review from anyone more familiar with coroutine sleeps. I'm guessing that your intent is to request a maximum timeout for a given operation to complete in, but to leave the sleep loop early if the operation completes earlier. I don't know if any existing coroutine code can be used to express that same idea. --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org --u3DzIyC2y4l9f20KSbx9jdWvT8BfqVwUw-- --2U6CC7xS62OVCcNoU9QxIrucDq4bDmSOK Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAlz50I8ACgkQp6FrSiUn Q2pN3Qf9E7uyYyZ7VYk4ilCQe+eZYdw6z0Fuz4960MtrMOJWF35QDH6603l0gU0r E9MOyINp1rO4TkP3+amMh73zC6o6SQjWMMfYK0Wzji0yBylfT1tDsD+f/+bNOm0c V6z1oY8LLUqwA2mopxX++IHWkV061nCZU2vgxx0Stxq5WLY5nHAsbcyaC/ITR2rz 3r/qNqNBh6m8yunoa5iVcmHYBN1Z4SsGlMIYTqtVouSPhDN9HLOBwTa/cGlqDn30 UXKqPaX31YbGI85FsKqFdRLi6G1aOUps5at9AjetowhiRaXRxldACFzxwbgrpmpG Q3FRMgveTor0H8Qv9VJbXcIsQxGKHA== =R2sV -----END PGP SIGNATURE----- --2U6CC7xS62OVCcNoU9QxIrucDq4bDmSOK--