74 lines
2.2 KiB
Diff
74 lines
2.2 KiB
Diff
Date: Wed, 26 Jun 2013 15:28:11 -0400
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From: Steven Rostedt <rostedt@goodmis.org>
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Subject: rt,ntp: Move call to schedule_delayed_work() to helper thread
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.8/older/patches-4.8.6-rt5.tar.xz
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The ntp code for notify_cmos_timer() is called from a hard interrupt
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context. schedule_delayed_work() under PREEMPT_RT_FULL calls spinlocks
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that have been converted to mutexes, thus calling schedule_delayed_work()
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from interrupt is not safe.
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Add a helper thread that does the call to schedule_delayed_work and wake
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up that thread instead of calling schedule_delayed_work() directly.
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This is only for CONFIG_PREEMPT_RT_FULL, otherwise the code still calls
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schedule_delayed_work() directly in irq context.
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Note: There's a few places in the kernel that do this. Perhaps the RT
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code should have a dedicated thread that does the checks. Just register
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a notifier on boot up for your check and wake up the thread when
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needed. This will be a todo.
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Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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[bigeasy: use swork_queue() instead a helper thread]
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/time/ntp.c | 26 ++++++++++++++++++++++++++
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1 file changed, 26 insertions(+)
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--- a/kernel/time/ntp.c
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+++ b/kernel/time/ntp.c
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@@ -17,6 +17,7 @@
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#include <linux/module.h>
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#include <linux/rtc.h>
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#include <linux/math64.h>
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+#include <linux/swork.h>
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#include "ntp_internal.h"
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#include "timekeeping_internal.h"
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@@ -568,10 +569,35 @@ static void sync_cmos_clock(struct work_
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&sync_cmos_work, timespec64_to_jiffies(&next));
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}
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+
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+static void run_clock_set_delay(struct swork_event *event)
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+{
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+ queue_delayed_work(system_power_efficient_wq, &sync_cmos_work, 0);
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+}
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+
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+static struct swork_event ntp_cmos_swork;
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+
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+void ntp_notify_cmos_timer(void)
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+{
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+ swork_queue(&ntp_cmos_swork);
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+}
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+
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+static __init int create_cmos_delay_thread(void)
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+{
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+ WARN_ON(swork_get());
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+ INIT_SWORK(&ntp_cmos_swork, run_clock_set_delay);
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+ return 0;
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+}
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+early_initcall(create_cmos_delay_thread);
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+
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+#else
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+
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void ntp_notify_cmos_timer(void)
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{
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queue_delayed_work(system_power_efficient_wq, &sync_cmos_work, 0);
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}
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+#endif /* CONFIG_PREEMPT_RT_FULL */
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#else
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void ntp_notify_cmos_timer(void) { }
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