Messages in this thread Patch in this message |  | | Subject | [RFC 7/12][PATCH] SCHED_DEADLINE: signal delivery when overrunning | From | Raistlin <> | Date | Fri, 16 Oct 2009 17:44:16 +0200 |
| |
Starting from this commit, the user can ask to receive a SIGXCPU signal every time the task runtime is overrun or a scheduling deadline is missed. This is done by means of the sched_flags field already present in sched_param_ex.
A runtime overrun will be quite common, e.g. due to coarse execution time accounting, wrong parameter assignement, etc. A deadline miss --since the deadlines the scheduler sees are ``scheduling deadlines'' which have not necessarily to be equal to task's deadlines-- is much more unlikely, and should only happen in an overloaded system.
Signed-off-by: Raistlin <raistlin@linux.it> --- include/linux/sched.h | 5 ++++ kernel/posix-cpu-timers.c | 52 +++++++++++++++++++++++++++++++++++++++++++- kernel/sched_deadline.c | 18 +++++++++++++++ 3 files changed, 73 insertions(+), 2 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h index fac928a..16668f9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -95,6 +95,9 @@ struct sched_param { #include <asm/processor.h> +#define SCHED_SIG_RORUN 0x80000000 +#define SCHED_SIG_DMISS 0x40000000 + struct sched_param_ex { int sched_priority; struct timespec sched_runtime; @@ -1229,6 +1232,8 @@ struct sched_rt_entity { #define DL_NEW 0x00000001 #define DL_THROTTLED 0x00000002 #define DL_BOOSTED 0x00000004 +#define DL_RORUN 0x00000008 +#define DL_DMISS 0x00000010 struct sched_dl_entity { struct rb_node rb_node; diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 5c9dc22..4caa5bf 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -1029,8 +1029,28 @@ static void check_thread_timers(struct task_struct *tsk, } /* - * Check for the special case thread timers. + * Check for the special case thread timers: + * - sched_deadline runtime/deadline overrun notification + * - sched_rt rlimit overrun notification */ + if (deadline_task(tsk) && (tsk->dl.flags & SCHED_SIG_RORUN || + tsk->dl.flags & SCHED_SIG_DMISS)) { + if (tsk->dl.flags & SCHED_SIG_RORUN && + tsk->dl.flags & DL_RORUN) { + tsk->dl.flags &= ~DL_RORUN; + printk(KERN_INFO "runtime overrun: %s[%d]\n", + tsk->comm, task_pid_nr(tsk)); + __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk); + } + if (tsk->dl.flags & SCHED_SIG_DMISS && + tsk->dl.flags & DL_DMISS) { + tsk->dl.flags &= ~DL_DMISS; + printk(KERN_INFO "scheduling deadline miss: %s[%d]\n", + tsk->comm, task_pid_nr(tsk)); + __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk); + } + } + if (sig->rlim[RLIMIT_RTTIME].rlim_cur != RLIM_INFINITY) { unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max; unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur; @@ -1129,6 +1149,9 @@ static void check_process_timers(struct task_struct *tsk, if (list_empty(&timers[CPUCLOCK_PROF]) && cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) && sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY && + !(deadline_task(tsk) && ((tsk->dl.flags & SCHED_SIG_RORUN && + tsk->dl.flags & DL_RORUN) || (tsk->dl.flags & SCHED_SIG_DMISS && + tsk->dl.flags & DL_DMISS))) && list_empty(&timers[CPUCLOCK_VIRT]) && cputime_eq(sig->it[CPUCLOCK_VIRT].expires, cputime_zero) && list_empty(&timers[CPUCLOCK_SCHED])) { @@ -1188,8 +1211,28 @@ static void check_process_timers(struct task_struct *tsk, } /* - * Check for the special case process timers. + * Check for the special case thread timers: + * - sched_deadline runtime/deadline overrun notification + * - sched_rt rlimit overrun notification */ + if (deadline_task(tsk) && (tsk->dl.flags & SCHED_SIG_RORUN || + tsk->dl.flags & SCHED_SIG_DMISS)) { + if (tsk->dl.flags & SCHED_SIG_RORUN && + tsk->dl.flags & DL_RORUN) { + tsk->dl.flags &= ~DL_RORUN; + printk(KERN_INFO "runtime overrun: %s[%d]\n", + tsk->comm, task_pid_nr(tsk)); + __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk); + } + if (tsk->dl.flags & SCHED_SIG_DMISS && + tsk->dl.flags & DL_DMISS) { + tsk->dl.flags &= ~DL_DMISS; + printk(KERN_INFO "scheduling deadline miss: %s[%d]\n", + tsk->comm, task_pid_nr(tsk)); + __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk); + } + } + check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF], &prof_expires, ptime, SIGPROF); check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime, @@ -1383,6 +1426,11 @@ static inline int fastpath_timer_check(struct task_struct *tsk) return 1; } + if (deadline_task(tsk) && + ((tsk->dl.flags & SCHED_SIG_RORUN && tsk->dl.flags & DL_RORUN) || + (tsk->dl.flags & SCHED_SIG_DMISS && tsk->dl.flags & DL_DMISS))) + return 1; + return sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY; } diff --git a/kernel/sched_deadline.c b/kernel/sched_deadline.c index f2c1b6e..7b57bb0 100644 --- a/kernel/sched_deadline.c +++ b/kernel/sched_deadline.c @@ -236,9 +236,27 @@ static void init_deadline_task(struct task_struct *p) static int deadline_runtime_exceeded(struct rq *rq, struct sched_dl_entity *dl_se) { + /* + * if the user asked for that, we have to inform him about + * a (scheduling) deadline miss ... + */ + if (unlikely(dl_se->flags & SCHED_SIG_DMISS && + deadline_time_before(dl_se->deadline, rq->clock))) + dl_se->flags |= DL_DMISS; + if (dl_se->runtime >= 0 || deadline_se_boosted(dl_se)) return 0; + /* + * ... and the same appies to runtime overruns. + * + * Note that (hopefully small) runtime overruns are very likely + * to occur, mainly due to accounting resolution, while missing a + * scheduling deadline should happen only on oversubscribed systems. + */ + if (dl_se->flags & SCHED_SIG_RORUN) + dl_se->flags |= DL_RORUN; + dequeue_deadline_entity(dl_se); if (!start_deadline_timer(dl_se, dl_se->deadline)) { replenish_deadline_entity(dl_se); -- 1.6.0.4
-- <<This happens because I choose it to happen!>> (Raistlin Majere) ---------------------------------------------------------------------- Dario Faggioli, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa (Italy) http://blog.linux.it/raistlin / raistlin@ekiga.net / dario.faggioli@jabber.org [unhandled content-type:application/pgp-signature] |  |