[RFC][PATCH 4/4] time: Introduce tk_fast_raw

From: Peter Zijlstra
Date: Thu Mar 19 2015 - 05:39:40 EST


Add the NMI safe CLOCK_MONOTONIC_RAW accessor..

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
kernel/time/timekeeping.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -59,6 +59,7 @@ struct tk_fast {
};

static struct tk_fast tk_fast_mono ____cacheline_aligned;
+static struct tk_fast tk_fast_raw ____cacheline_aligned;

/* flag for if timekeeping is suspended */
int __read_mostly timekeeping_suspended;
@@ -434,6 +435,12 @@ u64 ktime_get_mono_fast_ns(void)
}
EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);

+u64 ktime_get_raw_fast_ns(void)
+{
+ return __ktime_get_fast_ns(&tk_fast_raw);
+}
+EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
+
/* Suspend-time cycles value for halted fast timekeeper. */
static cycle_t cycles_at_suspend;

@@ -461,6 +468,11 @@ static void halt_fast_timekeeper(struct
cycles_at_suspend = tkr->read(tkr->clock);
tkr_dummy.read = dummy_clock_read;
update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
+
+ tkr = &tk->tkr_raw;
+ memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
+ tkr_dummy.read = dummy_clock_read;
+ update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
}

#ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
@@ -592,6 +604,7 @@ static void timekeeping_update(struct ti
sizeof(tk_core.timekeeper));

update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
+ update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
}

/**


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