diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2019-07-26 16:54:10 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-06-15 14:10:04 +0200 |
| commit | b4098bfc5efb1fd7ecf40165132a1283aeea3500 (patch) | |
| tree | 275717c66b810df5bbcd5afa04280897f9c5d475 | |
| parent | 9cc5b8656892a72438ee7deb5e80f5be47643b8b (diff) | |
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
| -rw-r--r-- | include/linux/sched/sysctl.h | 3 | ||||
| -rw-r--r-- | kernel/sched/deadline.c | 23 | ||||
| -rw-r--r-- | 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 660ac49f2b53..24be30a40814 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 504d2f51b0d6..f31964ad9c2e 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 db1ce7af2563..4aea67d3d552 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), |