From: tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, bigeasy@linutronix.de,
pbonzini@redhat.com, tglx@linutronix.de, hpa@zytor.com,
mingo@kernel.org, peterz@infradead.org
Subject: [tip:timers/core] KVM: LAPIC: Mark hrtimer to expire in hard interrupt context
Date: Tue, 30 Jul 2019 15:14:12 -0700 [thread overview]
Message-ID: <tip-899ad4bce00d10433b64647a37f6488dd8b582c9@git.kernel.org> (raw)
In-Reply-To: <20190726185753.363363474@linutronix.de>
Commit-ID: 899ad4bce00d10433b64647a37f6488dd8b582c9
Gitweb: https://git.kernel.org/tip/899ad4bce00d10433b64647a37f6488dd8b582c9
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Fri, 26 Jul 2019 20:30:55 +0200
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 30 Jul 2019 23:57:55 +0200
KVM: LAPIC: Mark hrtimer to expire in hard interrupt context
On PREEMPT_RT enabled kernels unmarked hrtimers are moved into soft
interrupt expiry mode by default.
While that's not a functional requirement for the KVM local APIC timer
emulation, it's a latency issue which can be avoided by marking the timer
so hard interrupt context expiry is enforced.
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: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190726185753.363363474@linutronix.de
---
arch/x86/kvm/lapic.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 0aa158657f20..b9e516099d07 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1601,7 +1601,7 @@ static void start_sw_tscdeadline(struct kvm_lapic *apic)
likely(ns > apic->lapic_timer.timer_advance_ns)) {
expire = ktime_add_ns(now, ns);
expire = ktime_sub_ns(expire, ktimer->timer_advance_ns);
- hrtimer_start(&ktimer->timer, expire, HRTIMER_MODE_ABS);
+ hrtimer_start(&ktimer->timer, expire, HRTIMER_MODE_ABS_HARD);
} else
apic_timer_expired(apic);
@@ -2302,7 +2302,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu, int timer_advance_ns)
apic->vcpu = vcpu;
hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC,
- HRTIMER_MODE_ABS);
+ HRTIMER_MODE_ABS_HARD);
apic->lapic_timer.timer.function = apic_timer_fn;
if (timer_advance_ns == -1) {
apic->lapic_timer.timer_advance_ns = LAPIC_TIMER_ADVANCE_ADJUST_INIT;
@@ -2487,7 +2487,7 @@ void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
timer = &vcpu->arch.apic->lapic_timer.timer;
if (hrtimer_cancel(timer))
- hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
+ hrtimer_start_expires(timer, HRTIMER_MODE_ABS_HARD);
}
/*
next prev parent reply other threads:[~2019-07-30 22:14 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-26 18:30 [patch 00/12] (hr)timers: Prepare for PREEMPT_RT support Thomas Gleixner
2019-07-26 18:30 ` [patch 01/12] hrtimer: Remove task argument from hrtimer_init_sleeper() Thomas Gleixner
2019-07-26 19:57 ` Steven Rostedt
2019-07-26 20:01 ` Thomas Gleixner
2019-07-30 22:07 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2019-07-26 18:30 ` [patch 02/12] hrtimer: Consolidate hrtimer_init() + hrtimer_init_sleeper() calls Thomas Gleixner
2019-07-30 22:08 ` [tip:timers/core] " tip-bot for Sebastian Andrzej Siewior
2019-08-01 15:49 ` tip-bot for Sebastian Andrzej Siewior
2019-07-26 18:30 ` [patch 03/12] hrtimer: Introduce HARD expiry mode Thomas Gleixner
2019-07-30 22:10 ` [tip:timers/core] " tip-bot for Sebastian Andrzej Siewior
2019-08-01 15:52 ` tip-bot for Sebastian Andrzej Siewior
2019-07-26 18:30 ` [patch 04/12] sched: Mark hrtimers to expire in hard interrupt context Thomas Gleixner
2019-07-30 22:11 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2019-08-01 15:53 ` tip-bot for Sebastian Andrzej Siewior
2019-08-01 18:58 ` tip-bot for Sebastian Andrzej Siewior
2019-07-26 18:30 ` [patch 05/12] perf/core: " Thomas Gleixner
2019-07-30 22:12 ` [tip:timers/core] " tip-bot for Thomas Gleixner
2019-08-01 15:54 ` tip-bot for Sebastian Andrzej Siewior
2019-08-01 18:59 ` tip-bot for Sebastian Andrzej Siewior
2019-07-26 18:30 ` [patch 06/12] watchdog: Mark watchdog_hrtimer " Thomas Gleixner
2019-07-30 22:13 ` [tip:timers/core] " tip-bot for Sebastian Andrzej Siewior
2019-08-01 15:55 ` tip-bot for Sebastian Andrzej Siewior
2019-08-01 19:00 ` tip-bot for Sebastian Andrzej Siewior
2019-07-26 18:30 ` [patch 07/12] KVM: LAPIC: Mark hrtimer " Thomas Gleixner
2019-07-26 19:41 ` Paolo Bonzini
2019-07-30 22:14 ` tip-bot for Sebastian Andrzej Siewior [this message]
2019-08-01 15:55 ` [tip:timers/core] " tip-bot for Sebastian Andrzej Siewior
2019-08-01 19:01 ` tip-bot for Sebastian Andrzej Siewior
2019-07-26 18:30 ` [patch 08/12] tick: Mark tick related hrtimers to expiry " Thomas Gleixner
2019-07-30 22:14 ` [tip:timers/core] " tip-bot for Sebastian Andrzej Siewior
2019-08-01 15:56 ` tip-bot for Sebastian Andrzej Siewior
2019-08-01 19:01 ` tip-bot for Sebastian Andrzej Siewior
2019-07-26 18:30 ` [patch 09/12] hrtimer: Move unmarked hrtimers to soft interrupt expiry on RT Thomas Gleixner
2019-07-30 22:15 ` [tip:timers/core] " tip-bot for Sebastian Andrzej Siewior
2019-08-01 15:57 ` tip-bot for Sebastian Andrzej Siewior
2019-08-01 19:02 ` tip-bot for Sebastian Andrzej Siewior
2019-07-26 18:30 ` [patch 10/12] hrtimer: Determine hard/soft expiry mode for hrtimer sleepers " Thomas Gleixner
2019-07-26 20:44 ` Steven Rostedt
2019-07-26 20:52 ` Thomas Gleixner
2019-07-26 20:56 ` Steven Rostedt
2019-07-26 21:16 ` Julia Cartwright
2019-07-26 21:30 ` Steven Rostedt
2019-07-26 21:35 ` Thomas Gleixner
2019-07-30 22:16 ` [tip:timers/core] " tip-bot for Sebastian Andrzej Siewior
2019-08-01 15:58 ` tip-bot for Sebastian Andrzej Siewior
2019-08-01 19:03 ` tip-bot for Sebastian Andrzej Siewior
2019-07-26 18:30 ` [patch 11/12] hrtimer: Prepare support for PREEMPT_RT Thomas Gleixner
2019-07-28 9:06 ` Juergen Gross
2019-07-29 15:08 ` Steven Rostedt
2019-07-29 17:30 ` Paolo Bonzini
2019-07-31 8:45 ` Juergen Gross
2019-07-30 22:17 ` [tip:timers/core] " tip-bot for Anna-Maria Gleixner
2019-08-01 15:58 ` tip-bot for Anna-Maria Gleixner
2019-08-01 19:04 ` tip-bot for Anna-Maria Gleixner
2019-08-20 13:26 ` Frederic Weisbecker
2019-08-23 2:12 ` [tip: timers/core] hrtimer: Improve comments on handling priority inversion against softirq kthread tip-bot2 for Frederic Weisbecker
2019-07-26 18:31 ` [patch 12/12] timers: Prepare support for PREEMPT_RT Thomas Gleixner
2019-07-30 22:17 ` [tip:timers/core] " tip-bot for Anna-Maria Gleixner
2019-08-01 15:59 ` tip-bot for Anna-Maria Gleixner
2019-08-01 19:04 ` tip-bot for Anna-Maria Gleixner
2019-07-29 19:45 ` [patch 00/12] (hr)timers: Prepare for PREEMPT_RT support Peter Zijlstra
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