[PATCH v2 26/37] hrtimer: Add clock bases and hrtimer mode for soft irq context

Anna-Maria Gleixner
2017-10-22T21:46:25Z

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From: Anna-Maria Gleixner <anna-maria@linutronix.de>

hrtimer callback functions are always executed in hard interrupt
context. Users of hrtimer which need their timer function to be executed
in soft interrupt context, make use of tasklets to get the proper context.

Add additional hrtimer clock bases for timers which must expire in softirq
context, so the detour via the tasklet can be avoided. This is also
required for RT, where the majority of hrtimer is moved into softirq
hrtimer context.

The selection of the expiry mode happens via a mode bit. Introduce
HRTIMER_MODE_SOFT and the matching combinations with the ABS/REL/PINNED
bits and update the decoding of hrtimer_mode in tracepoints.

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>

---
include/linux/hrtimer.h | 14 ++++++++++++++
include/trace/events/timer.h | 6 +++++-
kernel/time/hrtimer.c | 20 ++++++++++++++++++++
3 files changed, 39 insertions(+), 1 deletion(-)

--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -33,14 +33,24 @@ struct hrtimer_cpu_base;
* HRTIMER_MODE_REL - Time value is relative to now
* HRTIMER_MODE_PINNED - Timer is bound to CPU (is only considered
* when starting the timer)
+ * HRTIMER_MODE_SOFT - Timer callback function will be executed in
+ * soft irq context
*/
enum hrtimer_mode {
HRTIMER_MODE_ABS = 0x00,
HRTIMER_MODE_REL = 0x01,
HRTIMER_MODE_PINNED = 0x02,
+ HRTIMER_MODE_SOFT = 0x04,

HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED,
HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED,
+
+ HRTIMER_MODE_ABS_SOFT = HRTIMER_MODE_ABS | HRTIMER_MODE_SOFT,
+ HRTIMER_MODE_REL_SOFT = HRTIMER_MODE_REL | HRTIMER_MODE_SOFT,
+
+ HRTIMER_MODE_ABS_PINNED_SOFT = HRTIMER_MODE_ABS_PINNED | HRTIMER_MODE_SOFT,
+ HRTIMER_MODE_REL_PINNED_SOFT = HRTIMER_MODE_REL_PINNED | HRTIMER_MODE_SOFT,
+
};

/*
@@ -151,6 +161,10 @@ enum hrtimer_base_type {
HRTIMER_BASE_REALTIME,
HRTIMER_BASE_BOOTTIME,
HRTIMER_BASE_TAI,
+ HRTIMER_BASE_MONOTONIC_SOFT,
+ HRTIMER_BASE_REALTIME_SOFT,
+ HRTIMER_BASE_BOOTTIME_SOFT,
+ HRTIMER_BASE_TAI_SOFT,
HRTIMER_MAX_CLOCK_BASES,
};

--- a/include/trace/events/timer.h
+++ b/include/trace/events/timer.h
@@ -147,7 +147,11 @@ DEFINE_EVENT(timer_class, timer_cancel,
{ HRTIMER_MODE_ABS, "ABS" }, \
{ HRTIMER_MODE_REL, "REL" }, \
{ HRTIMER_MODE_ABS_PINNED, "ABS|PINNED" }, \
- { HRTIMER_MODE_REL_PINNED, "REL|PINNED" })
+ { HRTIMER_MODE_REL_PINNED, "REL|PINNED" }, \
+ { HRTIMER_MODE_ABS_SOFT, "ABS|SOFT" }, \
+ { HRTIMER_MODE_REL_SOFT, "REL|SOFT" }, \
+ { HRTIMER_MODE_ABS_PINNED_SOFT, "ABS|PINNED|SOFT" }, \
+ { HRTIMER_MODE_REL_PINNED_SOFT, "REL|PINNED|SOFT" })

/**
* hrtimer_init - called when the hrtimer is initialized
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -92,6 +92,26 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base,
.clockid = CLOCK_TAI,
.get_time = &ktime_get_clocktai,
},
+ {
+ .index = HRTIMER_BASE_MONOTONIC_SOFT,
+ .clockid = CLOCK_MONOTONIC,
+ .get_time = &ktime_get,
+ },
+ {
+ .index = HRTIMER_BASE_REALTIME_SOFT,
+ .clockid = CLOCK_REALTIME,
+ .get_time = &ktime_get_real,
+ },
+ {
+ .index = HRTIMER_BASE_BOOTTIME_SOFT,
+ .clockid = CLOCK_BOOTTIME,
+ .get_time = &ktime_get_boottime,
+ },
+ {
+ .index = HRTIMER_BASE_TAI_SOFT,
+ .clockid = CLOCK_TAI,
+ .get_time = &ktime_get_clocktai,
+ },
}
};