diff options
Diffstat (limited to 'libre/linux-libre-pae/0003-tick-Detect-and-fix-jiffies-update-stall.patch')
| -rw-r--r-- | libre/linux-libre-pae/0003-tick-Detect-and-fix-jiffies-update-stall.patch | 86 |
1 files changed, 0 insertions, 86 deletions
diff --git a/libre/linux-libre-pae/0003-tick-Detect-and-fix-jiffies-update-stall.patch b/libre/linux-libre-pae/0003-tick-Detect-and-fix-jiffies-update-stall.patch deleted file mode 100644 index 0d1985b9c..000000000 --- a/libre/linux-libre-pae/0003-tick-Detect-and-fix-jiffies-update-stall.patch +++ /dev/null @@ -1,86 +0,0 @@ -From 03b70547975933214e3edcbb3c99e05142172266 Mon Sep 17 00:00:00 2001 -From: Frederic Weisbecker <frederic@kernel.org> -Date: Wed, 2 Feb 2022 01:01:07 +0100 -Subject: [PATCH 3/7] tick: Detect and fix jiffies update stall - -On some rare cases, the timekeeper CPU may be delaying its jiffies -update duty for a while. Known causes include: - -* The timekeeper is waiting on stop_machine in a MULTI_STOP_DISABLE_IRQ - or MULTI_STOP_RUN state. Disabled interrupts prevent from timekeeping - updates while waiting for the target CPU to complete its - stop_machine() callback. - -* The timekeeper vcpu has VMEXIT'ed for a long while due to some overload - on the host. - -Detect and fix these situations with emergency timekeeping catchups. - -Original-patch-by: Paul E. McKenney <paulmck@kernel.org> -Signed-off-by: Frederic Weisbecker <frederic@kernel.org> -Cc: Thomas Gleixner <tglx@linutronix.de> ---- - kernel/time/tick-sched.c | 17 +++++++++++++++++ - kernel/time/tick-sched.h | 4 ++++ - 2 files changed, 21 insertions(+) - -diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c -index 5e80ee44c32a..0578c9301b17 100644 ---- a/kernel/time/tick-sched.c -+++ b/kernel/time/tick-sched.c -@@ -169,6 +169,8 @@ static ktime_t tick_init_jiffy_update(void) - return period; - } - -+#define MAX_STALLED_JIFFIES 5 -+ - static void tick_sched_do_timer(struct tick_sched *ts, ktime_t now) - { - int cpu = smp_processor_id(); -@@ -196,6 +198,21 @@ static void tick_sched_do_timer(struct tick_sched *ts, ktime_t now) - if (tick_do_timer_cpu == cpu) - tick_do_update_jiffies64(now); - -+ /* -+ * If jiffies update stalled for too long (timekeeper in stop_machine() -+ * or VMEXIT'ed for several msecs), force an update. -+ */ -+ if (ts->last_tick_jiffies != jiffies) { -+ ts->stalled_jiffies = 0; -+ ts->last_tick_jiffies = READ_ONCE(jiffies); -+ } else { -+ if (++ts->stalled_jiffies == MAX_STALLED_JIFFIES) { -+ tick_do_update_jiffies64(now); -+ ts->stalled_jiffies = 0; -+ ts->last_tick_jiffies = READ_ONCE(jiffies); -+ } -+ } -+ - if (ts->inidle) - ts->got_idle_tick = 1; - } -diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h -index d952ae393423..504649513399 100644 ---- a/kernel/time/tick-sched.h -+++ b/kernel/time/tick-sched.h -@@ -49,6 +49,8 @@ enum tick_nohz_mode { - * @timer_expires_base: Base time clock monotonic for @timer_expires - * @next_timer: Expiry time of next expiring timer for debugging purpose only - * @tick_dep_mask: Tick dependency mask - is set, if someone needs the tick -+ * @last_tick_jiffies: Value of jiffies seen on last tick -+ * @stalled_jiffies: Number of stalled jiffies detected across ticks - */ - struct tick_sched { - struct hrtimer sched_timer; -@@ -77,6 +79,8 @@ struct tick_sched { - u64 next_timer; - ktime_t idle_expires; - atomic_t tick_dep_mask; -+ unsigned long last_tick_jiffies; -+ unsigned int stalled_jiffies; - }; - - extern struct tick_sched *tick_get_tick_sched(int cpu); --- -2.36.1 - |