* [Qemu-devel] [PATCHv2 0/3] virtio-serial-bus: use a bh for flush_queued_data
@ 2011-04-28 12:04 Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 1/3] virtio-serial-bus: use bh for unthrottling Alon Levy
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Alon Levy @ 2011-04-28 12:04 UTC (permalink / raw)
To: qemu-devel
This replaces the direct call of flush_queued_data with a bottom half,
making the callpath for the chardev identical in a normal write and a write
resulting from unthrottling.
It includes a patch to add an accessor to QEMUBH to get scheduled status,
to keep the bh scheduled across migration.
Migration only trivially tested - just that it didn't break.
Alon Levy (3):
virtio-serial-bus: use bh for unthrottling
bh: add qemu_bh_is_scheduled
virtio-serial-bus: on migration send status of pending ports bh
async.c | 4 ++++
hw/virtio-serial-bus.c | 25 ++++++++++++++++++++-----
hw/virtio-serial.h | 5 +++++
qemu-common.h | 1 +
4 files changed, 30 insertions(+), 5 deletions(-)
--
1.7.4.4
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Qemu-devel] [PATCHv2 1/3] virtio-serial-bus: use bh for unthrottling
2011-04-28 12:04 [Qemu-devel] [PATCHv2 0/3] virtio-serial-bus: use a bh for flush_queued_data Alon Levy
@ 2011-04-28 12:04 ` Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 2/3] bh: add qemu_bh_is_scheduled Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 3/3] virtio-serial-bus: on migration send status of pending ports bh Alon Levy
2 siblings, 0 replies; 4+ messages in thread
From: Alon Levy @ 2011-04-28 12:04 UTC (permalink / raw)
To: qemu-devel
Instead of calling flush_queued_data when unthrottling, schedule
a bh. That way we can return immediately to the caller, and the
flush uses the same call path as a have_data for callbackee.
---
hw/virtio-serial-bus.c | 11 +++++++++--
hw/virtio-serial.h | 5 +++++
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index 6227379..8556e08 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -285,6 +285,13 @@ size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
return 0;
}
+static void bh_virtio_serial_flush_queued_data(void *opaque)
+{
+ VirtIOSerialPort *port = opaque;
+
+ flush_queued_data(port);
+}
+
void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
{
if (!port) {
@@ -295,8 +302,7 @@ void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle)
if (throttle) {
return;
}
-
- flush_queued_data(port);
+ qemu_bh_schedule(port->bh);
}
/* Guest wants to notify us of some event */
@@ -724,6 +730,7 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
bool plugging_port0;
port->vser = bus->vser;
+ port->bh = qemu_bh_new(bh_virtio_serial_flush_queued_data, port);
/*
* Is the first console port we're seeing? If so, put it up at
diff --git a/hw/virtio-serial.h b/hw/virtio-serial.h
index 5eb948e..0fa03d1 100644
--- a/hw/virtio-serial.h
+++ b/hw/virtio-serial.h
@@ -119,6 +119,11 @@ struct VirtIOSerialPort {
uint32_t iov_idx;
uint64_t iov_offset;
+ /*
+ * When unthrottling we use a buttomhalf to call flush_queued_data.
+ */
+ QEMUBH *bh;
+
/* Identify if this is a port that binds with hvc in the guest */
uint8_t is_console;
--
1.7.4.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [Qemu-devel] [PATCHv2 2/3] bh: add qemu_bh_is_scheduled
2011-04-28 12:04 [Qemu-devel] [PATCHv2 0/3] virtio-serial-bus: use a bh for flush_queued_data Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 1/3] virtio-serial-bus: use bh for unthrottling Alon Levy
@ 2011-04-28 12:04 ` Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 3/3] virtio-serial-bus: on migration send status of pending ports bh Alon Levy
2 siblings, 0 replies; 4+ messages in thread
From: Alon Levy @ 2011-04-28 12:04 UTC (permalink / raw)
To: qemu-devel
---
async.c | 4 ++++
qemu-common.h | 1 +
2 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/async.c b/async.c
index 57ac3a8..204716e 100644
--- a/async.c
+++ b/async.c
@@ -214,3 +214,7 @@ void qemu_bh_update_timeout(int *timeout)
}
}
+int qemu_bh_is_scheduled(QEMUBH *bh)
+{
+ return bh->scheduled;
+}
diff --git a/qemu-common.h b/qemu-common.h
index f9f705d..a107468 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -151,6 +151,7 @@ void qemu_bh_cancel(QEMUBH *bh);
void qemu_bh_delete(QEMUBH *bh);
int qemu_bh_poll(void);
void qemu_bh_update_timeout(int *timeout);
+int qemu_bh_is_scheduled(QEMUBH *bh);
void qemu_get_timedate(struct tm *tm, int offset);
int qemu_timedate_diff(struct tm *tm);
--
1.7.4.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [Qemu-devel] [PATCHv2 3/3] virtio-serial-bus: on migration send status of pending ports bh
2011-04-28 12:04 [Qemu-devel] [PATCHv2 0/3] virtio-serial-bus: use a bh for flush_queued_data Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 1/3] virtio-serial-bus: use bh for unthrottling Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 2/3] bh: add qemu_bh_is_scheduled Alon Levy
@ 2011-04-28 12:04 ` Alon Levy
2 siblings, 0 replies; 4+ messages in thread
From: Alon Levy @ 2011-04-28 12:04 UTC (permalink / raw)
To: qemu-devel
migration protocol bumped to 4, adding a single byte per port which is 1 if
there is a bh scheduled, 0 otherwise.
---
hw/virtio-serial-bus.c | 14 +++++++++++---
1 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index 8556e08..7fb8ade 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -536,7 +536,7 @@ static void virtio_serial_save(QEMUFile *f, void *opaque)
qemu_put_byte(f, port->guest_connected);
qemu_put_byte(f, port->host_connected);
- elem_popped = 0;
+ elem_popped = 0;
if (port->elem.out_num) {
elem_popped = 1;
}
@@ -548,6 +548,8 @@ static void virtio_serial_save(QEMUFile *f, void *opaque)
qemu_put_buffer(f, (unsigned char *)&port->elem,
sizeof(port->elem));
}
+ /* Pending bh */
+ qemu_put_byte(f, !!qemu_bh_is_scheduled(port->bh));
}
}
@@ -558,7 +560,7 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
uint32_t max_nr_ports, nr_active_ports, ports_map;
unsigned int i;
- if (version_id > 3) {
+ if (version_id > 4) {
return -EINVAL;
}
@@ -637,7 +639,13 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
virtio_serial_throttle_port(port, false);
}
}
+ if (version_id > 3) {
+ if (qemu_get_byte(f)) {
+ qemu_bh_schedule(port->bh);
+ }
+ }
}
+
return 0;
}
@@ -889,7 +897,7 @@ VirtIODevice *virtio_serial_init(DeviceState *dev, virtio_serial_conf *conf)
* Register for the savevm section with the virtio-console name
* to preserve backward compat
*/
- register_savevm(dev, "virtio-console", -1, 3, virtio_serial_save,
+ register_savevm(dev, "virtio-console", -1, 4, virtio_serial_save,
virtio_serial_load, vser);
return vdev;
--
1.7.4.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-04-28 12:04 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2011-04-28 12:04 [Qemu-devel] [PATCHv2 0/3] virtio-serial-bus: use a bh for flush_queued_data Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 1/3] virtio-serial-bus: use bh for unthrottling Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 2/3] bh: add qemu_bh_is_scheduled Alon Levy
2011-04-28 12:04 ` [Qemu-devel] [PATCHv2 3/3] virtio-serial-bus: on migration send status of pending ports bh Alon Levy
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