tick: Mark tick related hrtimers to expiry in hard interrupt context

The tick related hrtimers, which drive the scheduler tick and hrtimer based
broadcasting are required to expire in hard interrupt context for obvious
reasons.

Mark them so PREEMPT_RT kernels wont move them to soft interrupt expiry.

Make the horribly formatted RCU_NONIDLE bracket maze readable while at it.

No functional change,

[ tglx: Split out from larger combo patch. Add changelog ]

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190726185753.459144407@linutronix.de

diff --git a/kernel/time/tick-broadcast-hrtimer.c b/kernel/time/tick-broadcast-hrtimer.c
index 5be6154e2fd2c747518f8d6cdde6f917718a41cf..c1f5bb590b5e43b5a8598b789bc09157add53448 100644 (file)
--- a/kernel/time/tick-broadcast-hrtimer.c
+++ b/kernel/time/tick-broadcast-hrtimer.c
@@ -59,11 +59,16 @@ static int bc_set_next(ktime_t expires, struct clock_event_device *bc)
         * hrtimer_{start/cancel} functions call into tracing,
         * calls to these functions must be bound within RCU_NONIDLE.
         */
-       RCU_NONIDLE({
+       RCU_NONIDLE(
+               {
                        bc_moved = hrtimer_try_to_cancel(&bctimer) >= 0;
-                       if (bc_moved)
+                       if (bc_moved) {
                                hrtimer_start(&bctimer, expires,
-                                             HRTIMER_MODE_ABS_PINNED);});
+                                             HRTIMER_MODE_ABS_PINNED_HARD);
+                       }
+               }
+       );
+
        if (bc_moved) {
                /* Bind the "device" to the cpu */
                bc->bound_on = smp_processor_id();
@@ -104,7 +109,7 @@ static enum hrtimer_restart bc_handler(struct hrtimer *t)
 
 void tick_setup_hrtimer_broadcast(void)
 {
-       hrtimer_init(&bctimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+       hrtimer_init(&bctimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
        bctimer.function = bc_handler;
        clockevents_register_device(&ce_broadcast_hrtimer);
 }

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index be9707f68024912859006201443e4feca658512e..01ff32a02af2108f180f2206e6f0ddc8326ea61e 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -634,10 +634,12 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
        /* Forward the time to expire in the future */
        hrtimer_forward(&ts->sched_timer, now, tick_period);
 
-       if (ts->nohz_mode == NOHZ_MODE_HIGHRES)
-               hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED);
-       else
+       if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
+               hrtimer_start_expires(&ts->sched_timer,
+                                     HRTIMER_MODE_ABS_PINNED_HARD);
+       } else {
                tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1);
+       }
 
        /*
         * Reset to make sure next tick stop doesn't get fooled by past
@@ -802,7 +804,8 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu)
        }
 
        if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
-               hrtimer_start(&ts->sched_timer, tick, HRTIMER_MODE_ABS_PINNED);
+               hrtimer_start(&ts->sched_timer, tick,
+                             HRTIMER_MODE_ABS_PINNED_HARD);
        } else {
                hrtimer_set_expires(&ts->sched_timer, tick);
                tick_program_event(tick, 1);
@@ -1327,7 +1330,7 @@ void tick_setup_sched_timer(void)
        /*
         * Emulate tick processing via per-CPU hrtimers:
         */
-       hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+       hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
        ts->sched_timer.function = tick_sched_timer;
 
        /* Get the next period (per-CPU) */
@@ -1342,7 +1345,7 @@ void tick_setup_sched_timer(void)
        }
 
        hrtimer_forward(&ts->sched_timer, now, tick_period);
-       hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED);
+       hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD);
        tick_nohz_activate(ts, NOHZ_MODE_HIGHRES);
 }
 #endif /* HIGH_RES_TIMERS */