75 lines
2.4 KiB
Diff
75 lines
2.4 KiB
Diff
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From aa73fba3d63b8545159192725dbf8be085d875e7 Mon Sep 17 00:00:00 2001
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From: Mike Galbraith <efault@gmx.de>
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Date: Sun, 3 Sep 2017 04:48:10 +0200
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Subject: [PATCH 337/365] kernel/hrtimer/hotplug: don't wake ktimersoftd while
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holding the hrtimer base lock
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kernel/hrtimer: don't wakeup a process while holding the hrtimer base lock
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missed a path, namely hrtimers_dead_cpu() -> migrate_hrtimer_list(). Defer
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raising softirq until after base lock has been released there as well.
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Signed-off-by: Mike Galbraith <efault@gmx.de>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/time/hrtimer.c | 19 +++++++++++++------
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1 file changed, 13 insertions(+), 6 deletions(-)
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diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
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index bfe46fe6a700..b01e1fecdb25 100644
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--- a/kernel/time/hrtimer.c
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+++ b/kernel/time/hrtimer.c
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@@ -1848,7 +1848,7 @@ int hrtimers_prepare_cpu(unsigned int cpu)
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#ifdef CONFIG_HOTPLUG_CPU
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-static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
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+static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
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struct hrtimer_clock_base *new_base)
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{
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struct hrtimer *timer;
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@@ -1878,15 +1878,19 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
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}
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#ifdef CONFIG_PREEMPT_RT_BASE
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list_splice_tail(&old_base->expired, &new_base->expired);
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- if (!list_empty(&new_base->expired))
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- raise_softirq_irqoff(HRTIMER_SOFTIRQ);
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+ /*
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+ * Tell the caller to raise HRTIMER_SOFTIRQ. We can't safely
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+ * acquire ktimersoftd->pi_lock while the base lock is held.
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+ */
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+ return !list_empty(&new_base->expired);
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#endif
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+ return 0;
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}
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int hrtimers_dead_cpu(unsigned int scpu)
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{
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struct hrtimer_cpu_base *old_base, *new_base;
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- int i;
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+ int i, raise = 0;
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BUG_ON(cpu_online(scpu));
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tick_cancel_sched_timer(scpu);
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@@ -1902,13 +1906,16 @@ int hrtimers_dead_cpu(unsigned int scpu)
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raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
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for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
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- migrate_hrtimer_list(&old_base->clock_base[i],
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- &new_base->clock_base[i]);
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+ raise |= migrate_hrtimer_list(&old_base->clock_base[i],
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+ &new_base->clock_base[i]);
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}
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raw_spin_unlock(&old_base->lock);
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raw_spin_unlock(&new_base->lock);
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+ if (raise)
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+ raise_softirq_irqoff(HRTIMER_SOFTIRQ);
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+
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/* Check, if we got expired work to do */
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__hrtimer_peek_ahead_timers();
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local_irq_enable();
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--
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2.28.0
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