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| author | Paul E. McKenney <paulmck@kernel.org> | 2020-09-23 02:42:42 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-11-07 04:13:54 +0300 |
| commit | ab1b7880dec86bbdacd31a4c5cf104de4cf903f2 (patch) | |
| tree | 00b58346317e403e0a707fe666a0c6aa25a01830 /kernel/torture.c | |
| parent | c1e06287583e5ec496e4c02bf5b319e5e41a1fd2 (diff) | |
| download | linux-ab1b7880dec86bbdacd31a4c5cf104de4cf903f2.tar.xz | |
rcutorture: Make stutter_wait() caller restore priority
Currently, stutter_wait() will happily spin waiting for the stutter
interval to end even if the caller is running at a real-time priority
level. This could starve normal-priority tasks for no good reason. This
commit therefore drops the calling task's priority to SCHED_OTHER MAX_NICE
if stutter_wait() needs to wait. But when it waits, stutter_wait()
returns true, which allows the caller to restore the priority if needed.
Callers that were already running at SCHED_OTHER MAX_NICE obviously
do not need any changes, but this commit also restores priority for
higher-priority callers.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/torture.c')
| -rw-r--r-- | kernel/torture.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/kernel/torture.c b/kernel/torture.c index 56ff02bf444f..8562ac18d2eb 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -604,19 +604,19 @@ bool stutter_wait(const char *title) { ktime_t delay; unsigned int i = 0; - int oldnice; bool ret = false; int spt; cond_resched_tasks_rcu_qs(); spt = READ_ONCE(stutter_pause_test); for (; spt; spt = READ_ONCE(stutter_pause_test)) { - ret = true; + if (!ret) { + sched_set_normal(current, MAX_NICE); + ret = true; + } if (spt == 1) { schedule_timeout_interruptible(1); } else if (spt == 2) { - oldnice = task_nice(current); - set_user_nice(current, MAX_NICE); while (READ_ONCE(stutter_pause_test)) { if (!(i++ & 0xffff)) { set_current_state(TASK_INTERRUPTIBLE); @@ -625,7 +625,6 @@ bool stutter_wait(const char *title) } cond_resched(); } - set_user_nice(current, oldnice); } else { schedule_timeout_interruptible(round_jiffies_relative(HZ)); } |