[tip:timers/core] hrtimer: Prepare handling of hard and softirq based hrtimers

From: tip-bot for Anna-Maria Gleixner
Date: Mon Jan 15 2018 - 22:55:09 EST


Commit-ID: c458b1d102036eaa2c70e03000c959bd491c2037
Gitweb: https://git.kernel.org/tip/c458b1d102036eaa2c70e03000c959bd491c2037
Author: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
AuthorDate: Thu, 21 Dec 2017 11:41:56 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 16 Jan 2018 03:01:20 +0100

hrtimer: Prepare handling of hard and softirq based hrtimers

The softirq based hrtimer can utilize most of the existing hrtimers
functions, but need to operate on a different data set.

Add an 'active_mask' parameter to various functions so the hard and soft bases
can be selected. Fixup the existing callers and hand in the ACTIVE_HARD
mask.

Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: keescook@xxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20171221104205.7269-28-anna-maria@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/time/hrtimer.c | 38 +++++++++++++++++++++++++++++---------
1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index e2353f5..ba4674e 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -60,6 +60,15 @@
#include "tick-internal.h"

/*
+ * Masks for selecting the soft and hard context timers from
+ * cpu_base->active
+ */
+#define MASK_SHIFT (HRTIMER_BASE_MONOTONIC_SOFT)
+#define HRTIMER_ACTIVE_HARD ((1U << MASK_SHIFT) - 1)
+#define HRTIMER_ACTIVE_SOFT (HRTIMER_ACTIVE_HARD << MASK_SHIFT)
+#define HRTIMER_ACTIVE_ALL (HRTIMER_ACTIVE_SOFT | HRTIMER_ACTIVE_HARD)
+
+/*
* The timer bases:
*
* There are more clockids than hrtimer bases. Thus, we index
@@ -507,13 +516,24 @@ static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base,
return expires_next;
}

-static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
+/*
+ * Recomputes cpu_base::*next_timer and returns the earliest expires_next but
+ * does not set cpu_base::*expires_next, that is done by hrtimer_reprogram.
+ *
+ * @active_mask must be one of:
+ * - HRTIMER_ACTIVE,
+ * - HRTIMER_ACTIVE_SOFT, or
+ * - HRTIMER_ACTIVE_HARD.
+ */
+static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base,
+ unsigned int active_mask)
{
- unsigned int active = cpu_base->active_bases;
+ unsigned int active;
ktime_t expires_next = KTIME_MAX;

cpu_base->next_timer = NULL;

+ active = cpu_base->active_bases & active_mask;
expires_next = __hrtimer_next_event_base(cpu_base, active, expires_next);

return expires_next;
@@ -553,7 +573,7 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
{
ktime_t expires_next;

- expires_next = __hrtimer_get_next_event(cpu_base);
+ expires_next = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_HARD);

if (skip_equal && expires_next == cpu_base->expires_next)
return;
@@ -1074,7 +1094,7 @@ u64 hrtimer_get_next_event(void)
raw_spin_lock_irqsave(&cpu_base->lock, flags);

if (!__hrtimer_hres_active(cpu_base))
- expires = __hrtimer_get_next_event(cpu_base);
+ expires = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_HARD);

raw_spin_unlock_irqrestore(&cpu_base->lock, flags);

@@ -1248,10 +1268,10 @@ static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
}

static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now,
- unsigned long flags)
+ unsigned long flags, unsigned int active_mask)
{
struct hrtimer_clock_base *base;
- unsigned int active = cpu_base->active_bases;
+ unsigned int active = cpu_base->active_bases & active_mask;

for_each_active_base(base, cpu_base, active) {
struct timerqueue_node *node;
@@ -1314,10 +1334,10 @@ retry:
*/
cpu_base->expires_next = KTIME_MAX;

- __hrtimer_run_queues(cpu_base, now, flags);
+ __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD);

/* Reevaluate the clock bases for the next expiry */
- expires_next = __hrtimer_get_next_event(cpu_base);
+ expires_next = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_HARD);
/*
* Store the new expiry value so the migration code can verify
* against it.
@@ -1421,7 +1441,7 @@ void hrtimer_run_queues(void)

raw_spin_lock_irqsave(&cpu_base->lock, flags);
now = hrtimer_update_base(cpu_base);
- __hrtimer_run_queues(cpu_base, now, flags);
+ __hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD);
raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
}