diff options
| -rw-r--r-- | include/linux/init_task.h | 1 | ||||
| -rw-r--r-- | include/linux/prctl.h | 7 | ||||
| -rw-r--r-- | include/linux/sched.h | 6 | ||||
| -rw-r--r-- | kernel/fork.c | 2 | ||||
| -rw-r--r-- | kernel/sys.c | 10 |
5 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 021d8e720c7..23fd8909b9e 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -170,6 +170,7 @@ extern struct group_info init_groups; .cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \ .fs_excl = ATOMIC_INIT(0), \ .pi_lock = __SPIN_LOCK_UNLOCKED(tsk.pi_lock), \ + .timer_slack_ns = 50000, /* 50 usec default slack */ \ .pids = { \ [PIDTYPE_PID] = INIT_PID_LINK(PIDTYPE_PID), \ [PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID), \ diff --git a/include/linux/prctl.h b/include/linux/prctl.h index 5ad79198d6f..48d887e3c6e 100644 --- a/include/linux/prctl.h +++ b/include/linux/prctl.h @@ -78,4 +78,11 @@ #define PR_GET_SECUREBITS 27 #define PR_SET_SECUREBITS 28 +/* + * Get/set the timerslack as used by poll/select/nanosleep + * A value of 0 means "use default" + */ +#define PR_SET_TIMERSLACK 29 +#define PR_GET_TIMERSLACK 30 + #endif /* _LINUX_PRCTL_H */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 3d9120c5ad1..dcc03fd5a7f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1301,6 +1301,12 @@ struct task_struct { int latency_record_count; struct latency_record latency_record[LT_SAVECOUNT]; #endif + /* + * time slack values; these are used to round up poll() and + * select() etc timeout values. These are in nanoseconds. + */ + unsigned long timer_slack_ns; + unsigned long default_timer_slack_ns; }; /* diff --git a/kernel/fork.c b/kernel/fork.c index 7ce2ebe8479..4308d75f0fa 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -987,6 +987,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, p->prev_utime = cputime_zero; p->prev_stime = cputime_zero; + p->default_timer_slack_ns = current->timer_slack_ns; + #ifdef CONFIG_DETECT_SOFTLOCKUP p->last_switch_count = 0; p->last_switch_timestamp = 0; diff --git a/kernel/sys.c b/kernel/sys.c index 038a7bc0901..1b96401a057 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1727,6 +1727,16 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3, case PR_SET_TSC: error = SET_TSC_CTL(arg2); break; + case PR_GET_TIMERSLACK: + error = current->timer_slack_ns; + break; + case PR_SET_TIMERSLACK: + if (arg2 <= 0) + current->timer_slack_ns = + current->default_timer_slack_ns; + else + current->timer_slack_ns = arg2; + break; default: error = -EINVAL; break; |