linux-kernel - [patch 05/12] perf/core: Mark hrtimers to expire in hard interrupt context

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Date:   Fri, 26 Jul 2019 20:30:53 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Steven Rostedt <rostedt@...dmis.org>,
        Sebastian Siewior <bigeasy@...utronix.de>,
        Anna-Maria Gleixner <anna-maria@...utronix.de>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Juergen Gross <jgross@...e.com>
Subject: [patch 05/12] perf/core: Mark hrtimers to expire in hard interrupt
 context

From: Thomas Gleixner <tglx@...utronix.de>

To guarantee that the multiplexing mechanism and the hrtimer driven events
work on PREEMPT_RT enabled kernels it's required that the related hrtimers
expire in hard interrupt context. Mark them so PREEMPT_RT kernels wont
defer them to soft interrupt context.

No functional change.

[ tglx: Split out of larger combo patch. Added changelog ]

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Jiri Olsa <jolsa@...hat.com>
---
 kernel/events/core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1103,7 +1103,7 @@ static void __perf_mux_hrtimer_init(stru
 	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
 
 	raw_spin_lock_init(&cpuctx->hrtimer_lock);
-	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
+	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
 	timer->function = perf_mux_hrtimer_handler;
 }
 
@@ -1121,7 +1121,7 @@ static int perf_mux_hrtimer_restart(stru
 	if (!cpuctx->hrtimer_active) {
 		cpuctx->hrtimer_active = 1;
 		hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
-		hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
+		hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
 	}
 	raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);