Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer
On 10/14/07, Peter Zijlstra <[EMAIL PROTECTED]> wrote: > The below patch is an idea proposed by tglx and depends on sched-devel + > the hrtick patch previously posted. > > The current watchdog action is to demote the task to SCHED_NORMAL, > however it might be wanted to deliver a signal instead (or have more per > task configuration state). Which is why I added Lennart to the CC list > as I gathered he would like something like this for PulseAudio. Great, this looks very promising. Thanks for doing this. Kay - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer
On Sun, 14.10.07 00:51, Peter Zijlstra ([EMAIL PROTECTED]) wrote: > The below patch is an idea proposed by tglx and depends on sched-devel + > the hrtick patch previously posted. > > The current watchdog action is to demote the task to SCHED_NORMAL, > however it might be wanted to deliver a signal instead (or have more per > task configuration state). Which is why I added Lennart to the CC list > as I gathered he would like something like this for PulseAudio. Indeed! Having this in the kernel would allow us to enable RT scheduling for PulseAudio by default without bad effects. I was thinking about adding some kind of babysitting process to userspace -- but doing this as an RLIMIT in the kernel strikes me a much better idea! I think it would make a lot of sense to make the API very similar to RLIMIT_CPU, i.e. also send out SIGXCPU and SIGKILL, with the single difference that RLIMIT_CPU sends out a signal depending on the total CPU time used for the process and the new RLIMIT based on the time the process spent without sleeping. That would be a very reasonable extension to the current RLIMIT_CPU model. Thank you very much for doing this patch! Lennart -- Lennart PoetteringRed Hat, Inc. lennart [at] poettering [dot] net ICQ# 11060553 http://0pointer.net/lennart/ GnuPG 0x1A015CC4 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer
On Mon, 2007-10-15 at 15:26 +0200, Dmitry Adamushko wrote:
> On 14/10/2007, Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> > The below patch is an idea proposed by tglx and depends on sched-devel +
> > the hrtick patch previously posted.
> >
> > The current watchdog action is to demote the task to SCHED_NORMAL,
> > however it might be wanted to deliver a signal instead (or have more per
> > task configuration state). Which is why I added Lennart to the CC list
> > as I gathered he would like something like this for PulseAudio.
> >
> > ---
> > Subject: sched: SCHED_FIFO watchdog timer
>
> Why only SHCED_FIFO and not SCHED_RR?
> Their (mis)behavior is similar wrt SCHED_NORMAL tasks.
Because SCHED_FIFO is easier, _RR is for later. It was mostly an RFC to
request behavioural wishes from the users.
>
> > +#ifdef CONFIG_SCHED_HRT_TICK
> > +static int fifo_watchdog(struct rq *rq, struct task_struct *p, int queued)
> > +{
> > + if (likely(!queued || p->policy != SCHED_FIFO))
> > + return 0;
> > +
> > + /*
> > +* task has been naughty, turn into SCHED_NORMAL
> > +*/
> > + printk(KERN_INFO "SCHED_FIFO task %s/%d exceeded his runtime quota,"
> > + " demoting to regular task\n", p->comm,
> > task_pid_nr(p));
> > + deactivate_task(rq, p, 0);
> > + __setscheduler(rq, p, SCHED_NORMAL, 0);
> > + activate_task(rq, p, 0);
> > + resched_task(p);
>
> I guess, put_prev_task() / set_curr_task() should be called (for the
> case of task_running(p)) to make it group-scheduler-friendly (as it's
> done e.g. in sched_setscheduler()).
>
> (normilize_task() should probably do the same)
Right, that is where I copied from, I'll pull the functionality into a
single function and make this and the sysrq stuff use it.
Thanks!
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Description: This is a digitally signed message part
Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer
On 14/10/2007, Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> The below patch is an idea proposed by tglx and depends on sched-devel +
> the hrtick patch previously posted.
>
> The current watchdog action is to demote the task to SCHED_NORMAL,
> however it might be wanted to deliver a signal instead (or have more per
> task configuration state). Which is why I added Lennart to the CC list
> as I gathered he would like something like this for PulseAudio.
>
> ---
> Subject: sched: SCHED_FIFO watchdog timer
Why only SHCED_FIFO and not SCHED_RR?
Their (mis)behavior is similar wrt SCHED_NORMAL tasks.
> +#ifdef CONFIG_SCHED_HRT_TICK
> +static int fifo_watchdog(struct rq *rq, struct task_struct *p, int queued)
> +{
> + if (likely(!queued || p->policy != SCHED_FIFO))
> + return 0;
> +
> + /*
> +* task has been naughty, turn into SCHED_NORMAL
> +*/
> + printk(KERN_INFO "SCHED_FIFO task %s/%d exceeded his runtime quota,"
> + " demoting to regular task\n", p->comm,
> task_pid_nr(p));
> + deactivate_task(rq, p, 0);
> + __setscheduler(rq, p, SCHED_NORMAL, 0);
> + activate_task(rq, p, 0);
> + resched_task(p);
I guess, put_prev_task() / set_curr_task() should be called (for the
case of task_running(p)) to make it group-scheduler-friendly (as it's
done e.g. in sched_setscheduler()).
(normilize_task() should probably do the same)
--
Best regards,
Dmitry Adamushko
-
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Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer
On 14/10/2007, Peter Zijlstra [EMAIL PROTECTED] wrote:
The below patch is an idea proposed by tglx and depends on sched-devel +
the hrtick patch previously posted.
The current watchdog action is to demote the task to SCHED_NORMAL,
however it might be wanted to deliver a signal instead (or have more per
task configuration state). Which is why I added Lennart to the CC list
as I gathered he would like something like this for PulseAudio.
---
Subject: sched: SCHED_FIFO watchdog timer
Why only SHCED_FIFO and not SCHED_RR?
Their (mis)behavior is similar wrt SCHED_NORMAL tasks.
+#ifdef CONFIG_SCHED_HRT_TICK
+static int fifo_watchdog(struct rq *rq, struct task_struct *p, int queued)
+{
+ if (likely(!queued || p-policy != SCHED_FIFO))
+ return 0;
+
+ /*
+* task has been naughty, turn into SCHED_NORMAL
+*/
+ printk(KERN_INFO SCHED_FIFO task %s/%d exceeded his runtime quota,
+demoting to regular task\n, p-comm,
task_pid_nr(p));
+ deactivate_task(rq, p, 0);
+ __setscheduler(rq, p, SCHED_NORMAL, 0);
+ activate_task(rq, p, 0);
+ resched_task(p);
I guess, put_prev_task() / set_curr_task() should be called (for the
case of task_running(p)) to make it group-scheduler-friendly (as it's
done e.g. in sched_setscheduler()).
(normilize_task() should probably do the same)
--
Best regards,
Dmitry Adamushko
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer
On Mon, 2007-10-15 at 15:26 +0200, Dmitry Adamushko wrote:
On 14/10/2007, Peter Zijlstra [EMAIL PROTECTED] wrote:
The below patch is an idea proposed by tglx and depends on sched-devel +
the hrtick patch previously posted.
The current watchdog action is to demote the task to SCHED_NORMAL,
however it might be wanted to deliver a signal instead (or have more per
task configuration state). Which is why I added Lennart to the CC list
as I gathered he would like something like this for PulseAudio.
---
Subject: sched: SCHED_FIFO watchdog timer
Why only SHCED_FIFO and not SCHED_RR?
Their (mis)behavior is similar wrt SCHED_NORMAL tasks.
Because SCHED_FIFO is easier, _RR is for later. It was mostly an RFC to
request behavioural wishes from the users.
+#ifdef CONFIG_SCHED_HRT_TICK
+static int fifo_watchdog(struct rq *rq, struct task_struct *p, int queued)
+{
+ if (likely(!queued || p-policy != SCHED_FIFO))
+ return 0;
+
+ /*
+* task has been naughty, turn into SCHED_NORMAL
+*/
+ printk(KERN_INFO SCHED_FIFO task %s/%d exceeded his runtime quota,
+demoting to regular task\n, p-comm,
task_pid_nr(p));
+ deactivate_task(rq, p, 0);
+ __setscheduler(rq, p, SCHED_NORMAL, 0);
+ activate_task(rq, p, 0);
+ resched_task(p);
I guess, put_prev_task() / set_curr_task() should be called (for the
case of task_running(p)) to make it group-scheduler-friendly (as it's
done e.g. in sched_setscheduler()).
(normilize_task() should probably do the same)
Right, that is where I copied from, I'll pull the functionality into a
single function and make this and the sysrq stuff use it.
Thanks!
signature.asc
Description: This is a digitally signed message part
Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer
On Sun, 14.10.07 00:51, Peter Zijlstra ([EMAIL PROTECTED]) wrote: The below patch is an idea proposed by tglx and depends on sched-devel + the hrtick patch previously posted. The current watchdog action is to demote the task to SCHED_NORMAL, however it might be wanted to deliver a signal instead (or have more per task configuration state). Which is why I added Lennart to the CC list as I gathered he would like something like this for PulseAudio. Indeed! Having this in the kernel would allow us to enable RT scheduling for PulseAudio by default without bad effects. I was thinking about adding some kind of babysitting process to userspace -- but doing this as an RLIMIT in the kernel strikes me a much better idea! I think it would make a lot of sense to make the API very similar to RLIMIT_CPU, i.e. also send out SIGXCPU and SIGKILL, with the single difference that RLIMIT_CPU sends out a signal depending on the total CPU time used for the process and the new RLIMIT based on the time the process spent without sleeping. That would be a very reasonable extension to the current RLIMIT_CPU model. Thank you very much for doing this patch! Lennart -- Lennart PoetteringRed Hat, Inc. lennart [at] poettering [dot] net ICQ# 11060553 http://0pointer.net/lennart/ GnuPG 0x1A015CC4 - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer
On 10/14/07, Peter Zijlstra [EMAIL PROTECTED] wrote: The below patch is an idea proposed by tglx and depends on sched-devel + the hrtick patch previously posted. The current watchdog action is to demote the task to SCHED_NORMAL, however it might be wanted to deliver a signal instead (or have more per task configuration state). Which is why I added Lennart to the CC list as I gathered he would like something like this for PulseAudio. Great, this looks very promising. Thanks for doing this. Kay - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[RFC][PATCH] sched: SCHED_FIFO watchdog timer
The below patch is an idea proposed by tglx and depends on sched-devel +
the hrtick patch previously posted.
The current watchdog action is to demote the task to SCHED_NORMAL,
however it might be wanted to deliver a signal instead (or have more per
task configuration state). Which is why I added Lennart to the CC list
as I gathered he would like something like this for PulseAudio.
---
Subject: sched: SCHED_FIFO watchdog timer
Set a per task (rlimit based) limit on SCHED_FIFO runtime. When the
limit is exceeded the task is demoted back to SCHED_NORMAL.
Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]>
---
include/asm-generic/resource.h |5 +++--
kernel/sched.c |5 +
kernel/sched_rt.c | 36
3 files changed, 44 insertions(+), 2 deletions(-)
Index: linux-2.6/include/asm-generic/resource.h
===
--- linux-2.6.orig/include/asm-generic/resource.h
+++ linux-2.6/include/asm-generic/resource.h
@@ -44,8 +44,8 @@
#define RLIMIT_NICE13 /* max nice prio allowed to raise to
0-39 for nice level 19 .. -20 */
#define RLIMIT_RTPRIO 14 /* maximum realtime priority */
-
-#define RLIM_NLIMITS 15
+#define RLIMIT_FIFOTIME15 /* timeout for fifo slices in
us */
+#define RLIM_NLIMITS 16
/*
* SuS says limits have to be unsigned.
@@ -86,6 +86,7 @@
[RLIMIT_MSGQUEUE] = { MQ_BYTES_MAX, MQ_BYTES_MAX }, \
[RLIMIT_NICE] = { 0, 0 }, \
[RLIMIT_RTPRIO] = { 0, 0 }, \
+ [RLIMIT_FIFOTIME] = { RLIM_INFINITY, RLIM_INFINITY }, \
}
#endif /* __KERNEL__ */
Index: linux-2.6/kernel/sched_rt.c
===
--- linux-2.6.orig/kernel/sched_rt.c
+++ linux-2.6/kernel/sched_rt.c
@@ -89,6 +89,14 @@ static struct task_struct *pick_next_tas
next->se.exec_start = rq->clock;
+ if (next->policy == SCHED_FIFO) {
+ unsigned long fifotime;
+
+ fifotime = rq->curr->signal->rlim[RLIMIT_FIFOTIME].rlim_cur;
+ if (fifotime != RLIM_INFINITY)
+ hrtick_start(rq, (u64)fifotime * 1000, 0);
+ }
+
return next;
}
@@ -194,8 +202,36 @@ load_balance_rt(struct rq *this_rq, int
return load_moved;
}
+#ifdef CONFIG_SCHED_HRT_TICK
+static int fifo_watchdog(struct rq *rq, struct task_struct *p, int queued)
+{
+ if (likely(!queued || p->policy != SCHED_FIFO))
+ return 0;
+
+ /*
+* task has been naughty, turn into SCHED_NORMAL
+*/
+ printk(KERN_INFO "SCHED_FIFO task %s/%d exceeded his runtime quota,"
+ " demoting to regular task\n", p->comm, task_pid_nr(p));
+ deactivate_task(rq, p, 0);
+ __setscheduler(rq, p, SCHED_NORMAL, 0);
+ activate_task(rq, p, 0);
+ resched_task(p);
+
+ return 1;
+}
+#else
+static inline int fifo_watchdog(struct rq *rq, struct task_struct *p, int
queued)
+{
+ return 0;
+}
+#endif
+
static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
{
+ if (fifo_watchdog(rq, p, queued))
+ return;
+
/*
* RR tasks need a special form of timeslice management.
* FIFO tasks have no timeslices.
Index: linux-2.6/kernel/sched.c
===
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -132,6 +132,11 @@ static inline void sg_inc_cpu_power(stru
}
#endif
+static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep);
+static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
+static void
+__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio);
+
static inline int rt_policy(int policy)
{
if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR))
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[RFC][PATCH] sched: SCHED_FIFO watchdog timer
The below patch is an idea proposed by tglx and depends on sched-devel +
the hrtick patch previously posted.
The current watchdog action is to demote the task to SCHED_NORMAL,
however it might be wanted to deliver a signal instead (or have more per
task configuration state). Which is why I added Lennart to the CC list
as I gathered he would like something like this for PulseAudio.
---
Subject: sched: SCHED_FIFO watchdog timer
Set a per task (rlimit based) limit on SCHED_FIFO runtime. When the
limit is exceeded the task is demoted back to SCHED_NORMAL.
Signed-off-by: Peter Zijlstra [EMAIL PROTECTED]
---
include/asm-generic/resource.h |5 +++--
kernel/sched.c |5 +
kernel/sched_rt.c | 36
3 files changed, 44 insertions(+), 2 deletions(-)
Index: linux-2.6/include/asm-generic/resource.h
===
--- linux-2.6.orig/include/asm-generic/resource.h
+++ linux-2.6/include/asm-generic/resource.h
@@ -44,8 +44,8 @@
#define RLIMIT_NICE13 /* max nice prio allowed to raise to
0-39 for nice level 19 .. -20 */
#define RLIMIT_RTPRIO 14 /* maximum realtime priority */
-
-#define RLIM_NLIMITS 15
+#define RLIMIT_FIFOTIME15 /* timeout for fifo slices in
us */
+#define RLIM_NLIMITS 16
/*
* SuS says limits have to be unsigned.
@@ -86,6 +86,7 @@
[RLIMIT_MSGQUEUE] = { MQ_BYTES_MAX, MQ_BYTES_MAX }, \
[RLIMIT_NICE] = { 0, 0 }, \
[RLIMIT_RTPRIO] = { 0, 0 }, \
+ [RLIMIT_FIFOTIME] = { RLIM_INFINITY, RLIM_INFINITY }, \
}
#endif /* __KERNEL__ */
Index: linux-2.6/kernel/sched_rt.c
===
--- linux-2.6.orig/kernel/sched_rt.c
+++ linux-2.6/kernel/sched_rt.c
@@ -89,6 +89,14 @@ static struct task_struct *pick_next_tas
next-se.exec_start = rq-clock;
+ if (next-policy == SCHED_FIFO) {
+ unsigned long fifotime;
+
+ fifotime = rq-curr-signal-rlim[RLIMIT_FIFOTIME].rlim_cur;
+ if (fifotime != RLIM_INFINITY)
+ hrtick_start(rq, (u64)fifotime * 1000, 0);
+ }
+
return next;
}
@@ -194,8 +202,36 @@ load_balance_rt(struct rq *this_rq, int
return load_moved;
}
+#ifdef CONFIG_SCHED_HRT_TICK
+static int fifo_watchdog(struct rq *rq, struct task_struct *p, int queued)
+{
+ if (likely(!queued || p-policy != SCHED_FIFO))
+ return 0;
+
+ /*
+* task has been naughty, turn into SCHED_NORMAL
+*/
+ printk(KERN_INFO SCHED_FIFO task %s/%d exceeded his runtime quota,
+demoting to regular task\n, p-comm, task_pid_nr(p));
+ deactivate_task(rq, p, 0);
+ __setscheduler(rq, p, SCHED_NORMAL, 0);
+ activate_task(rq, p, 0);
+ resched_task(p);
+
+ return 1;
+}
+#else
+static inline int fifo_watchdog(struct rq *rq, struct task_struct *p, int
queued)
+{
+ return 0;
+}
+#endif
+
static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
{
+ if (fifo_watchdog(rq, p, queued))
+ return;
+
/*
* RR tasks need a special form of timeslice management.
* FIFO tasks have no timeslices.
Index: linux-2.6/kernel/sched.c
===
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -132,6 +132,11 @@ static inline void sg_inc_cpu_power(stru
}
#endif
+static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep);
+static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
+static void
+__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio);
+
static inline int rt_policy(int policy)
{
if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR))
-
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