From nobody Sat May 3 09:19:11 2025
Delivered-To: importer@patchew.org
Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as
permitted sender) client-ip=208.118.235.17;
envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org;
helo=lists.gnu.org;
Authentication-Results: mx.zoho.com;
spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted
sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org;
Return-Path: <qemu-devel-bounces+importer=patchew.org@nongnu.org>
Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by
mx.zohomail.com
with SMTPS id 1487679979888441.09033343591557;
Tue, 21 Feb 2017 04:26:19 -0800 (PST)
Received: from localhost ([::1]:44070 helo=lists.gnu.org)
by lists.gnu.org with esmtp (Exim 4.71)
(envelope-from <qemu-devel-bounces+importer=patchew.org@nongnu.org>)
id 1cg9WL-0007bX-9r
for importer@patchew.org; Tue, 21 Feb 2017 07:26:17 -0500
Received: from eggs.gnu.org ([2001:4830:134:3::10]:38602)
by lists.gnu.org with esmtp (Exim 4.71)
(envelope-from <stefanha@redhat.com>) id 1cg942-0006PF-HV
for qemu-devel@nongnu.org; Tue, 21 Feb 2017 06:57:03 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
(envelope-from <stefanha@redhat.com>) id 1cg940-0005Q8-Ra
for qemu-devel@nongnu.org; Tue, 21 Feb 2017 06:57:02 -0500
Received: from mx1.redhat.com ([209.132.183.28]:47364)
by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)
(Exim 4.71) (envelope-from <stefanha@redhat.com>) id 1cg940-0005Pr-JS
for qemu-devel@nongnu.org; Tue, 21 Feb 2017 06:57:00 -0500
Received: from int-mx13.intmail.prod.int.phx2.redhat.com
(int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26])
(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
(No client certificate requested)
by mx1.redhat.com (Postfix) with ESMTPS id A78C64DAF7;
Tue, 21 Feb 2017 11:57:00 +0000 (UTC)
Received: from localhost (ovpn-117-191.ams2.redhat.com [10.36.117.191])
by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP
id v1LBuxfO019260; Tue, 21 Feb 2017 06:56:59 -0500
From: Stefan Hajnoczi <stefanha@redhat.com>
To: <qemu-devel@nongnu.org>
Date: Tue, 21 Feb 2017 11:56:26 +0000
Message-Id: <20170221115644.28264-7-stefanha@redhat.com>
In-Reply-To: <20170221115644.28264-1-stefanha@redhat.com>
References: <20170221115644.28264-1-stefanha@redhat.com>
X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16
(mx1.redhat.com [10.5.110.29]);
Tue, 21 Feb 2017 11:57:00 +0000 (UTC)
X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]
[fuzzy]
X-Received-From: 209.132.183.28
Subject: [Qemu-devel] [PULL v2 06/24] io: make qio_channel_yield aware of
AioContexts
X-BeenThere: qemu-devel@nongnu.org
X-Mailman-Version: 2.1.21
Precedence: list
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel/>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
Cc: Peter Maydell <peter.maydell@linaro.org>,
Stefan Hajnoczi <stefanha@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>
Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org
Sender: "Qemu-devel" <qemu-devel-bounces+importer=patchew.org@nongnu.org>
X-ZohoMail: RSF_0 Z_629925259 SPT_0
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
From: Paolo Bonzini <pbonzini@redhat.com>
Support separate coroutines for reading and writing, and place the
read/write handlers on the AioContext that the QIOChannel is registered
with.
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213135235.12274-7-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
include/io/channel.h | 47 ++++++++++++++++++++++++++--
io/channel.c | 86 +++++++++++++++++++++++++++++++++++++++---------=
----
2 files changed, 109 insertions(+), 24 deletions(-)
diff --git a/include/io/channel.h b/include/io/channel.h
index 0bc7c3f..5d48906 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -23,6 +23,7 @@
=20
#include "qemu-common.h"
#include "qom/object.h"
+#include "qemu/coroutine.h"
#include "block/aio.h"
=20
#define TYPE_QIO_CHANNEL "qio-channel"
@@ -81,6 +82,9 @@ struct QIOChannel {
Object parent;
unsigned int features; /* bitmask of QIOChannelFeatures */
char *name;
+ AioContext *ctx;
+ Coroutine *read_coroutine;
+ Coroutine *write_coroutine;
#ifdef _WIN32
HANDLE event; /* For use with GSource on Win32 */
#endif
@@ -503,13 +507,50 @@ guint qio_channel_add_watch(QIOChannel *ioc,
=20
=20
/**
+ * qio_channel_attach_aio_context:
+ * @ioc: the channel object
+ * @ctx: the #AioContext to set the handlers on
+ *
+ * Request that qio_channel_yield() sets I/O handlers on
+ * the given #AioContext. If @ctx is %NULL, qio_channel_yield()
+ * uses QEMU's main thread event loop.
+ *
+ * You can move a #QIOChannel from one #AioContext to another even if
+ * I/O handlers are set for a coroutine. However, #QIOChannel provides
+ * no synchronization between the calls to qio_channel_yield() and
+ * qio_channel_attach_aio_context().
+ *
+ * Therefore you should first call qio_channel_detach_aio_context()
+ * to ensure that the coroutine is not entered concurrently. Then,
+ * while the coroutine has yielded, call qio_channel_attach_aio_context(),
+ * and then aio_co_schedule() to place the coroutine on the new
+ * #AioContext. The calls to qio_channel_detach_aio_context()
+ * and qio_channel_attach_aio_context() should be protected with
+ * aio_context_acquire() and aio_context_release().
+ */
+void qio_channel_attach_aio_context(QIOChannel *ioc,
+ AioContext *ctx);
+
+/**
+ * qio_channel_detach_aio_context:
+ * @ioc: the channel object
+ *
+ * Disable any I/O handlers set by qio_channel_yield(). With the
+ * help of aio_co_schedule(), this allows moving a coroutine that was
+ * paused by qio_channel_yield() to another context.
+ */
+void qio_channel_detach_aio_context(QIOChannel *ioc);
+
+/**
* qio_channel_yield:
* @ioc: the channel object
* @condition: the I/O condition to wait for
*
- * Yields execution from the current coroutine until
- * the condition indicated by @condition becomes
- * available.
+ * Yields execution from the current coroutine until the condition
+ * indicated by @condition becomes available. @condition must
+ * be either %G_IO_IN or %G_IO_OUT; it cannot contain both. In
+ * addition, no two coroutine can be waiting on the same condition
+ * and channel at the same time.
*
* This must only be called from coroutine context
*/
diff --git a/io/channel.c b/io/channel.c
index ce470d7..cdf7454 100644
--- a/io/channel.c
+++ b/io/channel.c
@@ -21,7 +21,7 @@
#include "qemu/osdep.h"
#include "io/channel.h"
#include "qapi/error.h"
-#include "qemu/coroutine.h"
+#include "qemu/main-loop.h"
=20
bool qio_channel_has_feature(QIOChannel *ioc,
QIOChannelFeature feature)
@@ -238,36 +238,80 @@ off_t qio_channel_io_seek(QIOChannel *ioc,
}
=20
=20
-typedef struct QIOChannelYieldData QIOChannelYieldData;
-struct QIOChannelYieldData {
- QIOChannel *ioc;
- Coroutine *co;
-};
+static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc);
=20
+static void qio_channel_restart_read(void *opaque)
+{
+ QIOChannel *ioc =3D opaque;
+ Coroutine *co =3D ioc->read_coroutine;
+
+ ioc->read_coroutine =3D NULL;
+ qio_channel_set_aio_fd_handlers(ioc);
+ aio_co_wake(co);
+}
=20
-static gboolean qio_channel_yield_enter(QIOChannel *ioc,
- GIOCondition condition,
- gpointer opaque)
+static void qio_channel_restart_write(void *opaque)
{
- QIOChannelYieldData *data =3D opaque;
- qemu_coroutine_enter(data->co);
- return FALSE;
+ QIOChannel *ioc =3D opaque;
+ Coroutine *co =3D ioc->write_coroutine;
+
+ ioc->write_coroutine =3D NULL;
+ qio_channel_set_aio_fd_handlers(ioc);
+ aio_co_wake(co);
}
=20
+static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc)
+{
+ IOHandler *rd_handler =3D NULL, *wr_handler =3D NULL;
+ AioContext *ctx;
+
+ if (ioc->read_coroutine) {
+ rd_handler =3D qio_channel_restart_read;
+ }
+ if (ioc->write_coroutine) {
+ wr_handler =3D qio_channel_restart_write;
+ }
+
+ ctx =3D ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
+ qio_channel_set_aio_fd_handler(ioc, ctx, rd_handler, wr_handler, ioc);
+}
+
+void qio_channel_attach_aio_context(QIOChannel *ioc,
+ AioContext *ctx)
+{
+ AioContext *old_ctx;
+ if (ioc->ctx =3D=3D ctx) {
+ return;
+ }
+
+ old_ctx =3D ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
+ qio_channel_set_aio_fd_handler(ioc, old_ctx, NULL, NULL, NULL);
+ ioc->ctx =3D ctx;
+ qio_channel_set_aio_fd_handlers(ioc);
+}
+
+void qio_channel_detach_aio_context(QIOChannel *ioc)
+{
+ ioc->read_coroutine =3D NULL;
+ ioc->write_coroutine =3D NULL;
+ qio_channel_set_aio_fd_handlers(ioc);
+ ioc->ctx =3D NULL;
+}
=20
void coroutine_fn qio_channel_yield(QIOChannel *ioc,
GIOCondition condition)
{
- QIOChannelYieldData data;
-
assert(qemu_in_coroutine());
- data.ioc =3D ioc;
- data.co =3D qemu_coroutine_self();
- qio_channel_add_watch(ioc,
- condition,
- qio_channel_yield_enter,
- &data,
- NULL);
+ if (condition =3D=3D G_IO_IN) {
+ assert(!ioc->read_coroutine);
+ ioc->read_coroutine =3D qemu_coroutine_self();
+ } else if (condition =3D=3D G_IO_OUT) {
+ assert(!ioc->write_coroutine);
+ ioc->write_coroutine =3D qemu_coroutine_self();
+ } else {
+ abort();
+ }
+ qio_channel_set_aio_fd_handlers(ioc);
qemu_coroutine_yield();
}
=20
--=20
2.9.3