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Date: Tue, 31 Oct 2017 13:28:37 +0100
From: Claudio Scordino <claudio@...dence.eu.com>
To: linux-kernel@...r.kernel.org
Cc: Juri Lelli <juri.lelli@...il.com>,
Claudio Scordino <claudio@...dence.eu.com>,
Luca Abeni <luca.abeni@...tannapisa.it>,
Tommaso Cucinotta <tommaso.cucinotta@...up.it>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Mathieu Poirier <mathieu.poirier@...aro.org>
Subject: [PATCH] sched/deadline: runtime overrun and deadline miss signals
From: Juri Lelli <juri.lelli@...il.com>
This patch adds the possibility to get the delivery of two signals
whenever there is a runtime overrun or a deadline miss, respectively.
The request is done through the sched_flags field within the sched_attr
structure.
Forward port of https://lkml.org/lkml/2009/10/16/170
Signed-off-by: Juri Lelli <juri.lelli@...il.com>
Signed-off-by: Claudio Scordino <claudio@...dence.eu.com>
Signed-off-by: Luca Abeni <luca.abeni@...tannapisa.it>
Cc: Tommaso Cucinotta <tommaso.cucinotta@...up.it>
CC: Peter Zijlstra <peterz@...radead.org>
CC: Ingo Molnar <mingo@...hat.com>
CC: Thomas Gleixner <tglx@...utronix.de>
Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
---
include/linux/sched.h | 8 ++++++++
include/uapi/linux/sched.h | 2 ++
kernel/sched/core.c | 3 ++-
kernel/sched/deadline.c | 13 +++++++++++++
kernel/time/posix-cpu-timers.c | 26 ++++++++++++++++++++++++++
5 files changed, 51 insertions(+), 1 deletion(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0f897df..285d1b4 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -473,11 +473,19 @@ struct sched_dl_entity {
* has not been executed yet. This flag is useful to avoid race
* conditions between the inactive timer handler and the wakeup
* code.
+ *
+ * @dl_overrun tells if the task asked to be informed about budget
+ * overruns.
+ *
+ * @dl_dmiss tells if the task asked to be informed about deadline
+ * misses.
*/
int dl_throttled : 1;
int dl_boosted : 1;
int dl_yielded : 1;
int dl_non_contending : 1;
+ int dl_overrun : 1;
+ int dl_dmiss : 1;
/*
* Bandwidth enforcement timer. Each -deadline task has its
diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h
index e2a6c7b..544be0c 100644
--- a/include/uapi/linux/sched.h
+++ b/include/uapi/linux/sched.h
@@ -48,5 +48,7 @@
*/
#define SCHED_FLAG_RESET_ON_FORK 0x01
#define SCHED_FLAG_RECLAIM 0x02
+#define SCHED_FLAG_DL_OVERRUN 0x04
+#define SCHED_FLAG_DL_DMISS 0x08
#endif /* _UAPI_LINUX_SCHED_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 97227df..d79df7a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4041,7 +4041,8 @@ static int __sched_setscheduler(struct task_struct *p,
}
if (attr->sched_flags &
- ~(SCHED_FLAG_RESET_ON_FORK | SCHED_FLAG_RECLAIM))
+ ~(SCHED_FLAG_RESET_ON_FORK | SCHED_FLAG_RECLAIM |
+ SCHED_FLAG_DL_OVERRUN | SCHED_FLAG_DL_DMISS))
return -EINVAL;
/*
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 8d1b946..8c1aa61 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1154,6 +1154,17 @@ static void update_curr_dl(struct rq *rq)
throttle:
if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
dl_se->dl_throttled = 1;
+
+ /*
+ * If requested, inform the user about deadline misses and/or
+ * runtime overruns.
+ */
+ if (unlikely(dl_se->flags & SCHED_FLAG_DL_DMISS &&
+ dl_time_before(dl_se->deadline, rq_clock(rq))))
+ dl_se->dl_dmiss = 1;
+ if (dl_se->flags & SCHED_FLAG_DL_OVERRUN)
+ dl_se->dl_overrun = 1;
+
__dequeue_task_dl(rq, curr, 0);
if (unlikely(dl_se->dl_boosted || !start_dl_timer(curr)))
enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH);
@@ -2565,6 +2576,8 @@ void __dl_clear_params(struct task_struct *p)
dl_se->dl_throttled = 0;
dl_se->dl_yielded = 0;
dl_se->dl_non_contending = 0;
+ dl_se->dl_overrun = 0;
+ dl_se->dl_dmiss = 0;
}
bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr)
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 8585ad6..f3616c5 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -13,6 +13,7 @@
#include <linux/tick.h>
#include <linux/workqueue.h>
#include <linux/compat.h>
+#include <linux/sched/deadline.h>
#include "posix-timers.h"
@@ -790,6 +791,22 @@ check_timers_list(struct list_head *timers,
return 0;
}
+static inline void check_dl_overrun(struct task_struct *tsk)
+{
+ if (tsk->dl.dl_overrun) {
+ tsk->dl.dl_overrun = 0;
+ pr_info("runtime overrun: %s[%d]\n",
+ tsk->comm, task_pid_nr(tsk));
+ __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
+ }
+ if (tsk->dl.dl_dmiss) {
+ tsk->dl.dl_dmiss = 0;
+ pr_info("scheduling deadline miss: %s[%d]\n",
+ tsk->comm, task_pid_nr(tsk));
+ __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
+ }
+}
+
/*
* Check for any per-thread CPU timers that have fired and move them off
* the tsk->cpu_timers[N] list onto the firing list. Here we update the
@@ -803,6 +820,9 @@ static void check_thread_timers(struct task_struct *tsk,
u64 expires;
unsigned long soft;
+ if (dl_task(tsk))
+ check_dl_overrun(tsk);
+
/*
* If cputime_expires is zero, then there are no active
* per thread CPU timers.
@@ -905,6 +925,9 @@ static void check_process_timers(struct task_struct *tsk,
struct task_cputime cputime;
unsigned long soft;
+ if (dl_task(tsk))
+ check_dl_overrun(tsk);
+
/*
* If cputimer is not running, then there are no active
* process wide timers (POSIX 1.b, itimers, RLIMIT_CPU).
@@ -1110,6 +1133,9 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
return 1;
}
+ if (dl_task(tsk) && (tsk->dl.dl_overrun || tsk->dl.dl_dmiss))
+ return 1;
+
return 0;
}
--
2.7.4
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