hrtimer: Add support for CLOCK_MONOTONIC_RAW (9c808765) · Commits · 戴 / test

The KVM/ARM timer implementation arms a hrtimer when a vcpu is blocked (usually because it is waiting for an interrupt) while its timer is going to kick in the future. It is essential that this timer doesn't get adjusted, or the guest will end up being woken-up at the wrong time (NTP running on the host seems to confuse the hell out of some guests). In order to allow this, let's add CLOCK_MONOTONIC_RAW support to hrtimer (it is so far only supported for posix timers). It also has the (limited) benefit of fixing ("mac80211_hwsim: shuffle code to prepare for dynamic radios"), which already uses this functionnality without realizing wasn't implemented (just being lucky...). Signed-off-by:

Marc Zyngier <marc.zyngier@arm.com> Cc: Tomasz Nowicki <tn@semihalf.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Link: http://lkml.kernel.org/r/1452879670-16133-2-git-send-email-marc.zyngier@arm.com Signed-off-by:

Thomas Gleixner <tglx@linutronix.de>

include/linux/hrtimer.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -151,6 +151,7 @@ enum hrtimer_base_type {
		HRTIMER_BASE_REALTIME,
		HRTIMER_BASE_BOOTTIME,
		HRTIMER_BASE_TAI,
		HRTIMER_BASE_MONOTONIC_RAW,
		HRTIMER_MAX_CLOCK_BASES,
		};

kernel/time/hrtimer.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -90,12 +90,18 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
		.clockid = CLOCK_TAI,
		.get_time = &ktime_get_clocktai,
		},
		{
		.index = HRTIMER_BASE_MONOTONIC_RAW,
		.clockid = CLOCK_MONOTONIC_RAW,
		.get_time = &ktime_get_raw,
		},
		}
		};

		static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
		[CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
		[CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
		[CLOCK_MONOTONIC_RAW] = HRTIMER_BASE_MONOTONIC_RAW,
		[CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
		[CLOCK_TAI] = HRTIMER_BASE_TAI,
		};
		@@ -1268,6 +1274,9 @@ static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now)
		if (!(active & 0x01))
		continue;

		if (unlikely(base->index == HRTIMER_BASE_MONOTONIC_RAW))
		basenow = ktime_get_raw();
		else
		basenow = ktime_add(now, base->offset);

		while ((node = timerqueue_getnext(&base->active))) {

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