diff options
| author | Ruchi Kandoi <kandoiruchi@google.com> | 2014-04-18 14:07:28 -0700 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2016-02-16 13:53:47 -0800 |
| commit | f2902f9065c5ec4f475367e5d39bdfff0d41fda6 (patch) | |
| tree | 6a571c318dce21975892b6f4f611422860efc8a2 /kernel/sys.c | |
| parent | e212fc789a243f170a2954143fd0743aa2a0f3c5 (diff) | |
prctl: adds PR_SET_TIMERSLACK_PID for setting timer slack of an arbitrary thread.
Second argument is similar to PR_SET_TIMERSLACK, if non-zero then the
slack is set to that value otherwise sets it to the default for the thread.
Takes PID of the thread as the third argument.
This allows power/performance management software to set timer slack for
other threads according to its policy for the thread (such as when the
thread is designated foreground vs. background activity)
Change-Id: I744d451ff4e60dae69f38f53948ff36c51c14a3f
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
Diffstat (limited to 'kernel/sys.c')
| -rw-r--r-- | kernel/sys.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/sys.c b/kernel/sys.c index 6af9212ab5aa..fd0680992912 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2076,6 +2076,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, unsigned long, arg4, unsigned long, arg5) { struct task_struct *me = current; + struct task_struct *tsk; unsigned char comm[sizeof(me->comm)]; long error; @@ -2199,6 +2200,23 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, else return -EINVAL; break; + case PR_SET_TIMERSLACK_PID: + rcu_read_lock(); + tsk = find_task_by_pid_ns((pid_t)arg3, &init_pid_ns); + if (tsk == NULL) { + rcu_read_unlock(); + return -EINVAL; + } + get_task_struct(tsk); + rcu_read_unlock(); + if (arg2 <= 0) + tsk->timer_slack_ns = + tsk->default_timer_slack_ns; + else + tsk->timer_slack_ns = arg2; + put_task_struct(tsk); + error = 0; + break; default: return -EINVAL; } |