From: Anna-Maria Behnsen <anna-maria@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
John Stultz <john.stultz@linaro.org>,
Eric Dumazet <edumazet@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
linux-pm@vger.kernel.org, Arjan van de Ven <arjan@infradead.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Rik van Riel <riel@redhat.com>,
Anna-Maria Behnsen <anna-maria@linutronix.de>
Subject: [PATCH v3 10/17] timer: Add get next timer interrupt functionality for remote CPUs
Date: Tue, 25 Oct 2022 15:58:43 +0200 [thread overview]
Message-ID: <20221025135850.51044-11-anna-maria@linutronix.de> (raw)
In-Reply-To: <20221025135850.51044-1-anna-maria@linutronix.de>
To prepare for the conversion of the NOHZ timer placement to a pull at
expiry time model it's required to have functionality available getting the
next timer interrupt on a remote CPU.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
kernel/time/tick-internal.h | 3 +++
kernel/time/timer.c | 41 +++++++++++++++++++++++++++++++++++++
2 files changed, 44 insertions(+)
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 6f5f164506d5..7b65abc9d803 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -170,6 +170,9 @@ DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
extern void forward_and_idle_timer_bases(unsigned long basej, u64 basem,
struct timer_events *tevt);
+extern void get_next_timer_interrupt_remote(unsigned long basej, u64 basem,
+ struct timer_events *tevt,
+ unsigned int cpu);
void timer_clear_idle(void);
#define CLOCK_SET_WALL \
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 167ae89f0f46..54631e86763f 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1744,6 +1744,47 @@ static unsigned long get_next_timer_interrupt(struct timer_base *base_local,
return local_first ? nextevt_local : nextevt_global;
}
+/**
+ * get_next_timer_interrupt_remote
+ * @basej: base time jiffies
+ * @basem: base time clock monotonic
+ * @tevt: Pointer to the storage for the expiry values
+ * @cpu: Remote CPU
+ *
+ * Stores the next pending local and global timer expiry values in the
+ * struct pointed to by @tevt. If a queue is empty the corresponding
+ * field is set to KTIME_MAX. If local event expires before global
+ * event, global event is set to KTIME_MAX as well.
+ */
+void get_next_timer_interrupt_remote(unsigned long basej, u64 basem,
+ struct timer_events *tevt,
+ unsigned int cpu)
+{
+ struct timer_base *base_local, *base_global;
+ unsigned long flags;
+
+ /* Preset local / global events */
+ tevt->local = tevt->global = KTIME_MAX;
+
+ /*
+ * Pretend that there is no timer pending if the cpu is offline.
+ * Possible pending timers will be migrated later to an active cpu.
+ */
+ if (cpu_is_offline(cpu))
+ return;
+
+ base_local = per_cpu_ptr(&timer_bases[BASE_LOCAL], cpu);
+ base_global = per_cpu_ptr(&timer_bases[BASE_GLOBAL], cpu);
+
+ raw_spin_lock_irqsave(&base_local->lock, flags);
+ raw_spin_lock_nested(&base_global->lock, SINGLE_DEPTH_NESTING);
+
+ get_next_timer_interrupt(base_local, base_global, basej, basem, tevt);
+
+ raw_spin_unlock(&base_global->lock);
+ raw_spin_unlock_irqrestore(&base_local->lock, flags);
+}
+
/**
* forward_and_idle_timer_bases
* @basej: base time jiffies
--
2.30.2
next prev parent reply other threads:[~2022-10-25 14:00 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-25 13:58 [PATCH v3 00/17] timer: Move from a push remote at enqueue to a pull at expiry model Anna-Maria Behnsen
2022-10-25 13:58 ` [PATCH v3 01/17] cpufreq: Prepare timer flags for hierarchical timer pull model Anna-Maria Behnsen
2022-10-26 13:54 ` Frederic Weisbecker
2022-10-31 15:22 ` Anna-Maria Behnsen
2022-10-25 13:58 ` [PATCH v3 02/17] tick-sched: Warn when next tick seems to be in the past Anna-Maria Behnsen
2022-10-25 22:11 ` Frederic Weisbecker
2022-10-25 13:58 ` [PATCH v3 03/17] timer: Move store of next event into __next_timer_interrupt() Anna-Maria Behnsen
2022-10-26 9:33 ` Frederic Weisbecker
2022-10-25 13:58 ` [PATCH v3 04/17] timer: Split next timer interrupt logic Anna-Maria Behnsen
2022-10-26 9:40 ` Frederic Weisbecker
2022-10-25 13:58 ` [PATCH v3 05/17] timer: Rework idle logic Anna-Maria Behnsen
2022-10-26 13:27 ` Frederic Weisbecker
2022-10-25 13:58 ` [PATCH v3 06/17] timer: Keep the pinned timers separate from the others Anna-Maria Behnsen
2022-10-26 15:26 ` Frederic Weisbecker
2022-10-25 13:58 ` [PATCH v3 07/17] timer: Retrieve next expiry of pinned/non-pinned timers seperately Anna-Maria Behnsen
2022-10-25 13:58 ` [PATCH v3 08/17] timer: Rename get_next_timer_interrupt() Anna-Maria Behnsen
2022-10-25 13:58 ` [PATCH v3 09/17] timer: Split out "get next timer interrupt" functionality Anna-Maria Behnsen
2022-10-25 13:58 ` Anna-Maria Behnsen [this message]
2022-10-25 13:58 ` [PATCH v3 11/17] timer: Restructure internal locking Anna-Maria Behnsen
2022-10-25 13:58 ` [PATCH v3 12/17] timer: Check if timers base is handled already Anna-Maria Behnsen
2022-10-25 13:58 ` [PATCH v3 13/17] tick/sched: Split out jiffies update helper function Anna-Maria Behnsen
2022-10-25 13:58 ` [PATCH v3 14/17] timer: Implement the hierarchical pull model Anna-Maria Behnsen
2022-10-25 16:36 ` kernel test robot
2022-10-26 5:35 ` kernel test robot
2022-10-27 7:38 ` kernel test robot
2022-10-25 13:58 ` [PATCH v3 15/17] timer_migration: Add tracepoints Anna-Maria Behnsen
2022-10-25 13:58 ` [PATCH v3 16/17] add_timer_on(): Make sure callers have TIMER_PINNED flag Anna-Maria Behnsen
2022-10-25 13:58 ` [PATCH v3 17/17] timer: Always queue timers on the local CPU Anna-Maria Behnsen
2022-10-27 7:22 ` kernel test robot
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