Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762210AbZJPPpA (ORCPT ); Fri, 16 Oct 2009 11:45:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761159AbZJPPpA (ORCPT ); Fri, 16 Oct 2009 11:45:00 -0400 Received: from ms01.sssup.it ([193.205.80.99]:54421 "EHLO sssup.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761348AbZJPPo6 (ORCPT ); Fri, 16 Oct 2009 11:44:58 -0400 Subject: [RFC 7/12][PATCH] SCHED_DEADLINE: signal delivery when overrunning From: Raistlin To: Peter Zijlstra Cc: linux-kernel , michael trimarchi , Fabio Checconi , Ingo Molnar , Thomas Gleixner , Dhaval Giani , Johan Eker , "p.faure" , Chris Friesen , Steven Rostedt , Henrik Austad , Frederic Weisbecker , Darren Hart , Sven-Thorsten Dietrich , Bjoern Brandenburg , Tommaso Cucinotta , "giuseppe.lipari" , Juri Lelli In-Reply-To: <1255707324.6228.448.camel@Palantir> References: <1255707324.6228.448.camel@Palantir> Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-yi4i88eMERXYpC4he7Np" Date: Fri, 16 Oct 2009 17:44:16 +0200 Message-Id: <1255707856.6228.461.camel@Palantir> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6957 Lines: 201 --=-yi4i88eMERXYpC4he7Np Content-Type: text/plain Content-Transfer-Encoding: quoted-printable 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 --- 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 { =20 #include =20 +#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 =20 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, } =20 /* - * 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 &=3D ~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 &=3D ~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 !=3D RLIM_INFINITY) { unsigned long hard =3D sig->rlim[RLIMIT_RTTIME].rlim_max; unsigned long *soft =3D &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 =3D=3D 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, } =20 /* - * 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 &=3D ~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 &=3D ~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_s= truct *tsk) return 1; } =20 + 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 !=3D RLIM_INFINITY; } =20 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 |=3D DL_DMISS; + if (dl_se->runtime >=3D 0 || deadline_se_boosted(dl_se)) return 0; =20 + /* + * ... 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 |=3D DL_RORUN; + dequeue_deadline_entity(dl_se); if (!start_deadline_timer(dl_se, dl_se->deadline)) { replenish_deadline_entity(dl_se); --=20 1.6.0.4 --=20 <> (Raistlin Majere) ---------------------------------------------------------------------- Dario Faggioli, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa (Italy) http://blog.linux.it/raistlin / raistlin@ekiga.net / dario.faggioli@jabber.org --=-yi4i88eMERXYpC4he7Np Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEABECAAYFAkrYlNAACgkQk4XaBE3IOsQuIACeOfthAU7fgPUO8y8paC9WMB9g Q9wAmwbiS61hRfyyuy0oxk8Zd1ca+goA =5WeL -----END PGP SIGNATURE----- --=-yi4i88eMERXYpC4he7Np-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/