Patchwork [v5,01/15] coroutine: add co_sleep_ns() coroutine sleep function

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Submitter Stefan Hajnoczi
Date Jan. 13, 2012, 1:14 p.m.
Message ID <1326460457-19446-2-git-send-email-stefanha@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/135828/
State New
Headers show

Comments

Stefan Hajnoczi - Jan. 13, 2012, 1:14 p.m.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 Makefile.objs          |    1 +
 qemu-coroutine-sleep.c |   38 ++++++++++++++++++++++++++++++++++++++
 qemu-coroutine.h       |    9 +++++++++
 3 files changed, 48 insertions(+), 0 deletions(-)
 create mode 100644 qemu-coroutine-sleep.c
Kevin Wolf - Jan. 17, 2012, 12:54 p.m.
Am 13.01.2012 14:14, schrieb Stefan Hajnoczi:
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> ---
>  Makefile.objs          |    1 +
>  qemu-coroutine-sleep.c |   38 ++++++++++++++++++++++++++++++++++++++
>  qemu-coroutine.h       |    9 +++++++++
>  3 files changed, 48 insertions(+), 0 deletions(-)
>  create mode 100644 qemu-coroutine-sleep.c
> 
> diff --git a/Makefile.objs b/Makefile.objs
> index 4f6d26c..f4f52e0 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -13,6 +13,7 @@ oslib-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o
>  #######################################################################
>  # coroutines
>  coroutine-obj-y = qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
> +coroutine-obj-y += qemu-coroutine-sleep.o
>  ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)
>  coroutine-obj-$(CONFIG_POSIX) += coroutine-ucontext.o
>  else
> diff --git a/qemu-coroutine-sleep.c b/qemu-coroutine-sleep.c
> new file mode 100644
> index 0000000..fd65274
> --- /dev/null
> +++ b/qemu-coroutine-sleep.c
> @@ -0,0 +1,38 @@
> +/*
> + * QEMU coroutine sleep
> + *
> + * Copyright IBM, Corp. 2011
> + *
> + * Authors:
> + *  Stefan Hajnoczi    <stefanha@linux.vnet.ibm.com>
> + *
> + * This work is licensed under the terms of the GNU LGPL, version 2 or later.
> + * See the COPYING.LIB file in the top-level directory.
> + *
> + */
> +
> +#include "qemu-coroutine.h"
> +#include "qemu-timer.h"
> +
> +typedef struct CoSleepCB {
> +    QEMUTimer *ts;
> +    Coroutine *co;
> +} CoSleepCB;
> +
> +static void co_sleep_cb(void *opaque)
> +{
> +    CoSleepCB *sleep_cb = opaque;
> +
> +    qemu_free_timer(sleep_cb->ts);

I think you need to call qemu_del_timer() first.

Kevin
Stefan Hajnoczi - Jan. 17, 2012, 1:31 p.m.
On Tue, Jan 17, 2012 at 12:54 PM, Kevin Wolf <kwolf@redhat.com> wrote:
> Am 13.01.2012 14:14, schrieb Stefan Hajnoczi:
>> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
>> ---
>>  Makefile.objs          |    1 +
>>  qemu-coroutine-sleep.c |   38 ++++++++++++++++++++++++++++++++++++++
>>  qemu-coroutine.h       |    9 +++++++++
>>  3 files changed, 48 insertions(+), 0 deletions(-)
>>  create mode 100644 qemu-coroutine-sleep.c
>>
>> diff --git a/Makefile.objs b/Makefile.objs
>> index 4f6d26c..f4f52e0 100644
>> --- a/Makefile.objs
>> +++ b/Makefile.objs
>> @@ -13,6 +13,7 @@ oslib-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o
>>  #######################################################################
>>  # coroutines
>>  coroutine-obj-y = qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
>> +coroutine-obj-y += qemu-coroutine-sleep.o
>>  ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)
>>  coroutine-obj-$(CONFIG_POSIX) += coroutine-ucontext.o
>>  else
>> diff --git a/qemu-coroutine-sleep.c b/qemu-coroutine-sleep.c
>> new file mode 100644
>> index 0000000..fd65274
>> --- /dev/null
>> +++ b/qemu-coroutine-sleep.c
>> @@ -0,0 +1,38 @@
>> +/*
>> + * QEMU coroutine sleep
>> + *
>> + * Copyright IBM, Corp. 2011
>> + *
>> + * Authors:
>> + *  Stefan Hajnoczi    <stefanha@linux.vnet.ibm.com>
>> + *
>> + * This work is licensed under the terms of the GNU LGPL, version 2 or later.
>> + * See the COPYING.LIB file in the top-level directory.
>> + *
>> + */
>> +
>> +#include "qemu-coroutine.h"
>> +#include "qemu-timer.h"
>> +
>> +typedef struct CoSleepCB {
>> +    QEMUTimer *ts;
>> +    Coroutine *co;
>> +} CoSleepCB;
>> +
>> +static void co_sleep_cb(void *opaque)
>> +{
>> +    CoSleepCB *sleep_cb = opaque;
>> +
>> +    qemu_free_timer(sleep_cb->ts);
>
> I think you need to call qemu_del_timer() first.

I think we're okay with just qemu_free_timer().  qemu_run_timers()
removes the timer from the active_timers list before invoking its
callback.  qemu_del_timer() is not needed because it just searches the
active_timers list and removes the timer, if found.  We're no longer
on the active_timers list at the point when co_sleep_cb() is called,
so there's no need.

Stefan
Kevin Wolf - Jan. 17, 2012, 1:38 p.m.
Am 17.01.2012 14:31, schrieb Stefan Hajnoczi:
> On Tue, Jan 17, 2012 at 12:54 PM, Kevin Wolf <kwolf@redhat.com> wrote:
>> Am 13.01.2012 14:14, schrieb Stefan Hajnoczi:
>>> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
>>> ---
>>>  Makefile.objs          |    1 +
>>>  qemu-coroutine-sleep.c |   38 ++++++++++++++++++++++++++++++++++++++
>>>  qemu-coroutine.h       |    9 +++++++++
>>>  3 files changed, 48 insertions(+), 0 deletions(-)
>>>  create mode 100644 qemu-coroutine-sleep.c
>>>
>>> diff --git a/Makefile.objs b/Makefile.objs
>>> index 4f6d26c..f4f52e0 100644
>>> --- a/Makefile.objs
>>> +++ b/Makefile.objs
>>> @@ -13,6 +13,7 @@ oslib-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o
>>>  #######################################################################
>>>  # coroutines
>>>  coroutine-obj-y = qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
>>> +coroutine-obj-y += qemu-coroutine-sleep.o
>>>  ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)
>>>  coroutine-obj-$(CONFIG_POSIX) += coroutine-ucontext.o
>>>  else
>>> diff --git a/qemu-coroutine-sleep.c b/qemu-coroutine-sleep.c
>>> new file mode 100644
>>> index 0000000..fd65274
>>> --- /dev/null
>>> +++ b/qemu-coroutine-sleep.c
>>> @@ -0,0 +1,38 @@
>>> +/*
>>> + * QEMU coroutine sleep
>>> + *
>>> + * Copyright IBM, Corp. 2011
>>> + *
>>> + * Authors:
>>> + *  Stefan Hajnoczi    <stefanha@linux.vnet.ibm.com>
>>> + *
>>> + * This work is licensed under the terms of the GNU LGPL, version 2 or later.
>>> + * See the COPYING.LIB file in the top-level directory.
>>> + *
>>> + */
>>> +
>>> +#include "qemu-coroutine.h"
>>> +#include "qemu-timer.h"
>>> +
>>> +typedef struct CoSleepCB {
>>> +    QEMUTimer *ts;
>>> +    Coroutine *co;
>>> +} CoSleepCB;
>>> +
>>> +static void co_sleep_cb(void *opaque)
>>> +{
>>> +    CoSleepCB *sleep_cb = opaque;
>>> +
>>> +    qemu_free_timer(sleep_cb->ts);
>>
>> I think you need to call qemu_del_timer() first.
> 
> I think we're okay with just qemu_free_timer().  qemu_run_timers()
> removes the timer from the active_timers list before invoking its
> callback.  qemu_del_timer() is not needed because it just searches the
> active_timers list and removes the timer, if found.  We're no longer
> on the active_timers list at the point when co_sleep_cb() is called,
> so there's no need.

Yes, seems you're right. qemu_del_timer() isn't a good name...

Kevin

Patch

diff --git a/Makefile.objs b/Makefile.objs
index 4f6d26c..f4f52e0 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -13,6 +13,7 @@  oslib-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o
 #######################################################################
 # coroutines
 coroutine-obj-y = qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
+coroutine-obj-y += qemu-coroutine-sleep.o
 ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)
 coroutine-obj-$(CONFIG_POSIX) += coroutine-ucontext.o
 else
diff --git a/qemu-coroutine-sleep.c b/qemu-coroutine-sleep.c
new file mode 100644
index 0000000..fd65274
--- /dev/null
+++ b/qemu-coroutine-sleep.c
@@ -0,0 +1,38 @@ 
+/*
+ * QEMU coroutine sleep
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Stefan Hajnoczi    <stefanha@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qemu-coroutine.h"
+#include "qemu-timer.h"
+
+typedef struct CoSleepCB {
+    QEMUTimer *ts;
+    Coroutine *co;
+} CoSleepCB;
+
+static void co_sleep_cb(void *opaque)
+{
+    CoSleepCB *sleep_cb = opaque;
+
+    qemu_free_timer(sleep_cb->ts);
+    qemu_coroutine_enter(sleep_cb->co, NULL);
+}
+
+void coroutine_fn co_sleep_ns(QEMUClock *clock, int64_t ns)
+{
+    CoSleepCB sleep_cb = {
+        .co = qemu_coroutine_self(),
+    };
+    sleep_cb.ts = qemu_new_timer(clock, SCALE_NS, co_sleep_cb, &sleep_cb);
+    qemu_mod_timer(sleep_cb.ts, qemu_get_clock_ns(clock) + ns);
+    qemu_coroutine_yield();
+}
diff --git a/qemu-coroutine.h b/qemu-coroutine.h
index 8a55fe1..34c15d4 100644
--- a/qemu-coroutine.h
+++ b/qemu-coroutine.h
@@ -17,6 +17,7 @@ 
 
 #include <stdbool.h>
 #include "qemu-queue.h"
+#include "qemu-timer.h"
 
 /**
  * Coroutines are a mechanism for stack switching and can be used for
@@ -199,4 +200,12 @@  void qemu_co_rwlock_wrlock(CoRwlock *lock);
  */
 void qemu_co_rwlock_unlock(CoRwlock *lock);
 
+/**
+ * Yield the coroutine for a given duration
+ *
+ * Note this function uses timers and hence only works when a main loop is in
+ * use.  See main-loop.h and do not use from qemu-tool programs.
+ */
+void coroutine_fn co_sleep_ns(QEMUClock *clock, int64_t ns);
+
 #endif /* QEMU_COROUTINE_H */