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From: "tip-bot2 for Peter Zijlstra" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>,
	x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [tip: sched/core] sched/deadline: Impose global limits on sched_attr::sched_period
Date: Tue, 16 Jun 2020 12:21:53 -0000
Message-ID: <159231011330.16989.6804741545941906806.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20190726161357.397880775@infradead.org>

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     b4098bfc5efb1fd7ecf40165132a1283aeea3500
Gitweb:        https://git.kernel.org/tip/b4098bfc5efb1fd7ecf40165132a1283aeea3500
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Fri, 26 Jul 2019 16:54:10 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 15 Jun 2020 14:10:04 +02:00

sched/deadline: Impose global limits on sched_attr::sched_period

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190726161357.397880775@infradead.org
---
 include/linux/sched/sysctl.h |  3 +++
 kernel/sched/deadline.c      | 23 +++++++++++++++++++++--
 kernel/sysctl.c              | 14 ++++++++++++++
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h
index 660ac49..24be30a 100644
--- a/include/linux/sched/sysctl.h
+++ b/include/linux/sched/sysctl.h
@@ -61,6 +61,9 @@ int sched_proc_update_handler(struct ctl_table *table, int write,
 extern unsigned int sysctl_sched_rt_period;
 extern int sysctl_sched_rt_runtime;
 
+extern unsigned int sysctl_sched_dl_period_max;
+extern unsigned int sysctl_sched_dl_period_min;
+
 #ifdef CONFIG_UCLAMP_TASK
 extern unsigned int sysctl_sched_uclamp_util_min;
 extern unsigned int sysctl_sched_uclamp_util_max;
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 504d2f5..f31964a 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2635,6 +2635,14 @@ void __getparam_dl(struct task_struct *p, struct sched_attr *attr)
 }
 
 /*
+ * Default limits for DL period; on the top end we guard against small util
+ * tasks still getting rediculous long effective runtimes, on the bottom end we
+ * guard against timer DoS.
+ */
+unsigned int sysctl_sched_dl_period_max = 1 << 22; /* ~4 seconds */
+unsigned int sysctl_sched_dl_period_min = 100;     /* 100 us */
+
+/*
  * This function validates the new parameters of a -deadline task.
  * We ask for the deadline not being zero, and greater or equal
  * than the runtime, as well as the period of being zero or
@@ -2646,6 +2654,8 @@ void __getparam_dl(struct task_struct *p, struct sched_attr *attr)
  */
 bool __checkparam_dl(const struct sched_attr *attr)
 {
+	u64 period, max, min;
+
 	/* special dl tasks don't actually use any parameter */
 	if (attr->sched_flags & SCHED_FLAG_SUGOV)
 		return true;
@@ -2669,12 +2679,21 @@ bool __checkparam_dl(const struct sched_attr *attr)
 	    attr->sched_period & (1ULL << 63))
 		return false;
 
+	period = attr->sched_period;
+	if (!period)
+		period = attr->sched_deadline;
+
 	/* runtime <= deadline <= period (if period != 0) */
-	if ((attr->sched_period != 0 &&
-	     attr->sched_period < attr->sched_deadline) ||
+	if (period < attr->sched_deadline ||
 	    attr->sched_deadline < attr->sched_runtime)
 		return false;
 
+	max = (u64)READ_ONCE(sysctl_sched_dl_period_max) * NSEC_PER_USEC;
+	min = (u64)READ_ONCE(sysctl_sched_dl_period_min) * NSEC_PER_USEC;
+
+	if (period < min || period > max)
+		return false;
+
 	return true;
 }
 
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index db1ce7a..4aea67d 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1780,6 +1780,20 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= sched_rt_handler,
 	},
 	{
+		.procname	= "sched_deadline_period_max_us",
+		.data		= &sysctl_sched_dl_period_max,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "sched_deadline_period_min_us",
+		.data		= &sysctl_sched_dl_period_min,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
 		.procname	= "sched_rr_timeslice_ms",
 		.data		= &sysctl_sched_rr_timeslice,
 		.maxlen		= sizeof(int),

  parent reply index

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-26 14:54 [RFC][PATCH 00/13] SCHED_DEADLINE server infrastructure Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 01/13] sched/deadline: Impose global limits on sched_attr::sched_period Peter Zijlstra
2019-07-29  8:57   ` Juri Lelli
2019-07-29 11:45     ` Daniel Bristot de Oliveira
2019-08-02 17:21   ` Alessio Balsini
2019-08-05 11:53     ` Peter Zijlstra
2019-08-22 12:29       ` Alessio Balsini
2019-08-22 16:51         ` Peter Zijlstra
2019-08-31 14:41           ` Alessio Balsini
2019-09-02  9:16             ` Peter Zijlstra
2019-09-02 12:31               ` Peter Zijlstra
2019-09-04 10:16               ` Steven Rostedt
2019-09-04 11:30                 ` Peter Zijlstra
2019-09-04 13:24                   ` Joel Fernandes
2019-09-04 14:11                     ` Will Deacon
2019-09-04 14:35                       ` Joel Fernandes
2019-09-04 15:52                     ` Peter Zijlstra
2019-10-23 17:17       ` [PATCH 4.4 4.9 4.14] loop: Add LOOP_SET_DIRECT_IO to compat ioctl Alessio Balsini
2019-10-23 17:22         ` Alessio Balsini
2019-10-25  0:17         ` Sasha Levin
2020-05-20 18:38   ` [RFC][PATCH 01/13] sched/deadline: Impose global limits on sched_attr::sched_period Juri Lelli
2020-05-21 13:45     ` Daniel Bristot de Oliveira
2020-06-16 12:21   ` tip-bot2 for Peter Zijlstra [this message]
2019-07-26 14:54 ` [RFC][PATCH 02/13] stop_machine: Fix stop_cpus_in_progress ordering Peter Zijlstra
2019-07-30 13:16   ` Phil Auld
2019-07-30 13:22   ` Steven Rostedt
2019-07-26 14:54 ` [RFC][PATCH 03/13] sched: Fix kerneldoc comment for ia64_set_curr_task Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 04/13] sched/{rt,deadline}: Fix set_next_task vs pick_next_task Peter Zijlstra
2019-07-29  9:25   ` Juri Lelli
2019-07-29 11:15     ` Peter Zijlstra
2019-07-29 11:27       ` Juri Lelli
2019-07-29 13:04         ` Peter Zijlstra
2019-07-29 13:17           ` Juri Lelli
2019-07-29 14:40             ` Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 05/13] sched: Add task_struct pointer to sched_class::set_curr_task Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 06/13] sched/fair: Export newidle_balance() Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 07/13] sched: Allow put_prev_task() to drop rq->lock Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 08/13] sched: Rework pick_next_task() slow-path Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 09/13] sched: Unify runtime accounting across classes Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 10/13] sched/deadline: Collect sched_dl_entity initialization Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 11/13] sched/deadline: Move bandwidth accounting into {en,de}queue_dl_entity Peter Zijlstra
2019-07-26 14:54 ` [RFC][PATCH 12/13] sched/deadline: Introduce deadline servers Peter Zijlstra
2019-08-07 16:31   ` Dietmar Eggemann
2019-08-08  6:52     ` Juri Lelli
2019-08-08  7:52       ` Dietmar Eggemann
2019-08-08  7:56     ` Peter Zijlstra
2019-08-08  8:11       ` Dietmar Eggemann
2019-08-08  8:46         ` Juri Lelli
2019-08-08  8:57           ` Dietmar Eggemann
2019-08-08  9:27             ` Juri Lelli
2019-08-08  9:45               ` Juri Lelli
2019-08-30 11:24                 ` Peter Zijlstra
2019-09-06  9:36                   ` Juri Lelli
2019-08-08 10:31           ` Peter Zijlstra
2019-08-09  7:13             ` Juri Lelli
2019-08-08  6:59   ` Juri Lelli
2019-08-09  9:17   ` Dietmar Eggemann
2019-08-09 12:16     ` Juri Lelli
2019-07-26 14:54 ` [RFC][PATCH 13/13] sched/fair: Add trivial fair server Peter Zijlstra
2019-07-26 20:01 ` [RFC][PATCH 00/13] SCHED_DEADLINE server infrastructure luca abeni
2019-09-03 14:27 ` Alessio Balsini
2019-09-04 10:50   ` Juri Lelli
2019-09-04 11:32     ` Peter Zijlstra

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