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authorThomas Gleixner <tglx@linutronix.de>2021-07-13 15:39:50 +0200
committerThomas Gleixner <tglx@linutronix.de>2021-08-10 17:57:22 +0200
commit66f7b0c8aadd2785fc29f2c71477ebc16f4e38cc (patch)
tree9a248c6ed85efc63d1299653de76991c7f280d2a
parente71a4153b7c256ec103e79875398553808aeffd2 (diff)
timerfd: Provide timerfd_resume()
Resuming timekeeping is a clock-was-set event and uses the clock-was-set notification mechanism. This is in the way of making the clock-was-set update for hrtimers selective so unnecessary IPIs are avoided when a CPU base does not have timers queued which are affected by the clock setting. Provide a seperate timerfd_resume() interface so the resume logic and the clock-was-set mechanism can be distangled in the core code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210713135158.395287410@linutronix.de
-rw-r--r--fs/timerfd.c16
-rw-r--r--include/linux/hrtimer.h2
2 files changed, 18 insertions, 0 deletions
diff --git a/fs/timerfd.c b/fs/timerfd.c
index c5509d2448e3..e9c96a0c79f1 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -115,6 +115,22 @@ void timerfd_clock_was_set(void)
rcu_read_unlock();
}
+static void timerfd_resume_work(struct work_struct *work)
+{
+ timerfd_clock_was_set();
+}
+
+static DECLARE_WORK(timerfd_work, timerfd_resume_work);
+
+/*
+ * Invoked from timekeeping_resume(). Defer the actual update to work so
+ * timerfd_clock_was_set() runs in task context.
+ */
+void timerfd_resume(void)
+{
+ schedule_work(&timerfd_work);
+}
+
static void __timerfd_remove_cancel(struct timerfd_ctx *ctx)
{
if (ctx->might_cancel) {
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 77295af72426..253c6e25f331 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -349,8 +349,10 @@ hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
#ifdef CONFIG_TIMERFD
extern void timerfd_clock_was_set(void);
+extern void timerfd_resume(void);
#else
static inline void timerfd_clock_was_set(void) { }
+static inline void timerfd_resume(void) { }
#endif
extern void hrtimers_resume(void);