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authorThomas Gleixner <tglx@linutronix.de>2018-01-15 01:30:51 +0300
committerIngo Molnar <mingo@kernel.org>2018-01-16 04:35:44 +0300
commitae67badaa1643253998cb21d5782e4ea7c231a29 (patch)
tree9d12382a6e79d9d6420796d2cca2c6853b9aeed2 /include/linux/hrtimer.h
parent57957fb519449803df30d10da433c27aaad17fa5 (diff)
downloadlinux-ae67badaa1643253998cb21d5782e4ea7c231a29.tar.xz
hrtimer: Optimize the hrtimer code by using static keys for migration_enable/nohz_active
The hrtimer_cpu_base::migration_enable and ::nohz_active fields were originally introduced to avoid accessing global variables for these decisions. Still that results in a (cache hot) load and conditional branch, which can be avoided by using static keys. Implement it with static keys and optimize for the most critical case of high performance networking which tends to disable the timer migration functionality. No change in functionality. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: keescook@chromium.org Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1801142327490.2371@nanos Link: https://lkml.kernel.org/r/20171221104205.7269-2-anna-maria@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/hrtimer.h')
-rw-r--r--include/linux/hrtimer.h4
1 files changed, 0 insertions, 4 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 012c37fdb688..79b2a8d29d8c 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -153,8 +153,6 @@ enum hrtimer_base_type {
* @cpu: cpu number
* @active_bases: Bitfield to mark bases with active timers
* @clock_was_set_seq: Sequence counter of clock was set events
- * @migration_enabled: The migration of hrtimers to other cpus is enabled
- * @nohz_active: The nohz functionality is enabled
* @expires_next: absolute time of the next event which was scheduled
* via clock_set_next_event()
* @next_timer: Pointer to the first expiring timer
@@ -178,8 +176,6 @@ struct hrtimer_cpu_base {
unsigned int cpu;
unsigned int active_bases;
unsigned int clock_was_set_seq;
- bool migration_enabled;
- bool nohz_active;
#ifdef CONFIG_HIGH_RES_TIMERS
unsigned int in_hrtirq : 1,
hres_active : 1,