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authorJuri Lelli <juri.lelli@gmail.com>2017-12-12 12:10:24 +0100
committerIngo Molnar <mingo@kernel.org>2018-01-10 11:30:31 +0100
commit34be39305a77b8b1ec9f279163c7cdb6cc719b91 (patch)
tree1d970e5d92e508630d575814a3bae1181ed85348
parent7332dec055f2457c386032f7e9b2991eb05c2a0a (diff)
sched/deadline: Implement "runtime overrun signal" support
This patch adds the possibility of getting the delivery of a SIGXCPU signal whenever there is a runtime overrun. 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 Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Juri Lelli <juri.lelli@gmail.com> Signed-off-by: Claudio Scordino <claudio@evidence.eu.com> Signed-off-by: Luca Abeni <luca.abeni@santannapisa.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it> Link: http://lkml.kernel.org/r/1513077024-25461-1-git-send-email-claudio@evidence.eu.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--include/linux/sched.h4
-rw-r--r--include/uapi/linux/sched.h5
-rw-r--r--kernel/sched/core.c3
-rw-r--r--kernel/sched/deadline.c7
-rw-r--r--kernel/time/posix-cpu-timers.c18
5 files changed, 35 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d2588263a989..274a449c805a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -472,11 +472,15 @@ 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 runtime
+ * overruns.
*/
unsigned int dl_throttled : 1;
unsigned int dl_boosted : 1;
unsigned int dl_yielded : 1;
unsigned int dl_non_contending : 1;
+ unsigned int dl_overrun : 1;
/*
* Bandwidth enforcement timer. Each -deadline task has its
diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h
index 30a9e51bbb1e..22627f80063e 100644
--- a/include/uapi/linux/sched.h
+++ b/include/uapi/linux/sched.h
@@ -49,5 +49,10 @@
*/
#define SCHED_FLAG_RESET_ON_FORK 0x01
#define SCHED_FLAG_RECLAIM 0x02
+#define SCHED_FLAG_DL_OVERRUN 0x04
+
+#define SCHED_FLAG_ALL (SCHED_FLAG_RESET_ON_FORK | \
+ SCHED_FLAG_RECLAIM | \
+ SCHED_FLAG_DL_OVERRUN)
#endif /* _UAPI_LINUX_SCHED_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a794f8155cd5..e28391bf8b04 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4085,8 +4085,7 @@ recheck:
return -EINVAL;
}
- if (attr->sched_flags &
- ~(SCHED_FLAG_RESET_ON_FORK | SCHED_FLAG_RECLAIM))
+ if (attr->sched_flags & ~SCHED_FLAG_ALL)
return -EINVAL;
/*
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 2473736c7616..4c666dbe5038 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1155,6 +1155,12 @@ 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 runtime overruns. */
+ if (dl_runtime_exceeded(dl_se) &&
+ (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);
@@ -2566,6 +2572,7 @@ 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;
}
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 1f27887aa194..cf50ea34dbd1 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -14,6 +14,7 @@
#include <linux/tick.h>
#include <linux/workqueue.h>
#include <linux/compat.h>
+#include <linux/sched/deadline.h>
#include "posix-timers.h"
@@ -791,6 +792,14 @@ 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;
+ __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
@@ -804,6 +813,9 @@ 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.
@@ -906,6 +918,9 @@ 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).
@@ -1111,6 +1126,9 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
return 1;
}
+ if (dl_task(tsk) && tsk->dl.dl_overrun)
+ return 1;
+
return 0;
}