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

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Date:   Mon, 15 Jan 2018 19:51:41 -0800
From:   tip-bot for Anna-Maria Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mingo@...nel.org, hpa@...or.com, hch@....de, peterz@...radead.org,
        linux-kernel@...r.kernel.org, john.stultz@...aro.org,
        tglx@...utronix.de, torvalds@...ux-foundation.org,
        anna-maria@...utronix.de
Subject: [tip:timers/core] hrtimer: Prepare handling of hard and softirq
 based hrtimers

Commit-ID:  c458b1d102036eaa2c70e03000c959bd491c2037
Gitweb:     https://git.kernel.org/tip/c458b1d102036eaa2c70e03000c959bd491c2037
Author:     Anna-Maria Gleixner <anna-maria@...utronix.de>
AuthorDate: Thu, 21 Dec 2017 11:41:56 +0100
Committer:  Ingo Molnar <mingo@...nel.org>
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@...utronix.de>
Cc: Christoph Hellwig <hch@....de>
Cc: John Stultz <john.stultz@...aro.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: keescook@...omium.org
Link: http://lkml.kernel.org/r/20171221104205.7269-28-anna-maria@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 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);
 }