Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752152AbdLLLVr (ORCPT ); Tue, 12 Dec 2017 06:21:47 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:36578 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751234AbdLLLVn (ORCPT ); Tue, 12 Dec 2017 06:21:43 -0500 X-Google-Smtp-Source: ACJfBouyqny0k50mc57jxpts+MaA/OhX0o0WYmMLdz3ZornI8hOdyrKdjKgNyB+mRa2imL0OiRoSRA== From: Claudio Scordino To: Peter Zijlstra Cc: Juri Lelli , Claudio Scordino , Luca Abeni , Tommaso Cucinotta , Ingo Molnar , Thomas Gleixner , LKML , linux-rt-users Subject: [PATCH v3] sched/deadline: runtime overrun signal Date: Tue, 12 Dec 2017 12:10:24 +0100 Message-Id: <1513077024-25461-1-git-send-email-claudio@evidence.eu.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5229 Lines: 166 From: Juri Lelli 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 Signed-off-by: Juri Lelli Signed-off-by: Claudio Scordino Signed-off-by: Luca Abeni Tested-by: Mathieu Poirier Cc: Tommaso Cucinotta CC: Peter Zijlstra CC: Ingo Molnar CC: Thomas Gleixner CC: LKML CC: linux-rt-users --- Changes from v2: - do not use a dubious signed bitfield for the dl_overrun flag Changes from v1: - fix: do not send the signal in case of yield (reported by Mathieu Poirier) - removed the deadline miss signal because not needed in most of the cases --- include/linux/sched.h | 4 ++++ include/uapi/linux/sched.h | 1 + kernel/sched/core.c | 3 ++- kernel/sched/deadline.c | 7 +++++++ kernel/time/posix-cpu-timers.c | 20 ++++++++++++++++++++ 5 files changed, 34 insertions(+), 1 deletion(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 21991d6..a62a2f1 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 30a9e51..beb8ecd 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -49,5 +49,6 @@ */ #define SCHED_FLAG_RESET_ON_FORK 0x01 #define SCHED_FLAG_RECLAIM 0x02 +#define SCHED_FLAG_DL_OVERRUN 0x04 #endif /* _UAPI_LINUX_SCHED_H */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 75554f3..5bb67af 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)) return -EINVAL; /* diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 2473736..72554d1 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 1f27887a..48281d9 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 +792,16 @@ 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); + } +} + /* * 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 +815,9 @@ 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 +920,9 @@ 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 +1128,9 @@ static inline int fastpath_timer_check(struct task_struct *tsk) return 1; } + if (dl_task(tsk) && tsk->dl.dl_overrun) + return 1; + return 0; } -- 2.7.4