From 34be39305a77b8b1ec9f279163c7cdb6cc719b91 Mon Sep 17 00:00:00 2001 From: Juri Lelli Date: Tue, 12 Dec 2017 12:10:24 +0100 Subject: 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 Signed-off-by: Juri Lelli Signed-off-by: Claudio Scordino Signed-off-by: Luca Abeni Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tommaso Cucinotta Link: http://lkml.kernel.org/r/1513077024-25461-1-git-send-email-claudio@evidence.eu.com Signed-off-by: Ingo Molnar --- include/linux/sched.h | 4 ++++ include/uapi/linux/sched.h | 5 +++++ kernel/sched/core.c | 3 +-- kernel/sched/deadline.c | 7 +++++++ kernel/time/posix-cpu-timers.c | 18 ++++++++++++++++++ 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 #include #include +#include #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; } -- cgit