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Date: Thu, 26 Feb 2015 09:48:50 +0100
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: Joakim Hernberg <jhernberg@...hemy.lu>
Cc: Daniel Wagner <wagi@...om.org>, John Kacur <jkacur@...hat.com>,
linux-rt-users <linux-rt-users@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>, rostedt@...dmis.org
Subject: Re: [ANNOUNCE] 3.18.7-rt1
* Sebastian Andrzej Siewior | 2015-02-25 14:55:01 [+0100]:
>Okay. I applied a slightly modified version of it. That init() is
>From 8334ac498f104c00e5d93e3e83d3bcec1a993cec Mon Sep 17 00:00:00 2001
From: Daniel Wagner <wagi@...om.org>
Date: Tue, 17 Feb 2015 09:37:44 +0100
Subject: [PATCH] thermal: Defer thermal wakups to threads
On RT the spin lock in pkg_temp_thermal_platfrom_thermal_notify will
call schedule while we run in irq context.
[<ffffffff816850ac>] dump_stack+0x4e/0x8f
[<ffffffff81680f7d>] __schedule_bug+0xa6/0xb4
[<ffffffff816896b4>] __schedule+0x5b4/0x700
[<ffffffff8168982a>] schedule+0x2a/0x90
[<ffffffff8168a8b5>] rt_spin_lock_slowlock+0xe5/0x2d0
[<ffffffff8168afd5>] rt_spin_lock+0x25/0x30
[<ffffffffa03a7b75>] pkg_temp_thermal_platform_thermal_notify+0x45/0x134 [x86_pkg_temp_thermal]
[<ffffffff8103d4db>] ? therm_throt_process+0x1b/0x160
[<ffffffff8103d831>] intel_thermal_interrupt+0x211/0x250
[<ffffffff8103d8c1>] smp_thermal_interrupt+0x21/0x40
[<ffffffff8169415d>] thermal_interrupt+0x6d/0x80
Let's defer the work to a kthread.
Signed-off-by: Daniel Wagner <daniel.wagner@...-carit.de>
[bigeasy: reoder init/denit position. TODO: flush swork on exit]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
drivers/thermal/x86_pkg_temp_thermal.c | 51 ++++++++++++++++++++++++++++++++--
1 file changed, 48 insertions(+), 3 deletions(-)
diff --git a/drivers/thermal/x86_pkg_temp_thermal.c b/drivers/thermal/x86_pkg_temp_thermal.c
index 9ea3d9d49ffc..ab7c400a9d5c 100644
--- a/drivers/thermal/x86_pkg_temp_thermal.c
+++ b/drivers/thermal/x86_pkg_temp_thermal.c
@@ -29,6 +29,7 @@
#include <linux/pm.h>
#include <linux/thermal.h>
#include <linux/debugfs.h>
+#include <linux/work-simple.h>
#include <asm/cpu_device_id.h>
#include <asm/mce.h>
@@ -352,7 +353,7 @@ static void pkg_temp_thermal_threshold_work_fn(struct work_struct *work)
}
}
-static int pkg_temp_thermal_platform_thermal_notify(__u64 msr_val)
+static void platform_thermal_notify_work(struct swork_event *event)
{
unsigned long flags;
int cpu = smp_processor_id();
@@ -369,7 +370,7 @@ static int pkg_temp_thermal_platform_thermal_notify(__u64 msr_val)
pkg_work_scheduled[phy_id]) {
disable_pkg_thres_interrupt();
spin_unlock_irqrestore(&pkg_work_lock, flags);
- return -EINVAL;
+ return;
}
pkg_work_scheduled[phy_id] = 1;
spin_unlock_irqrestore(&pkg_work_lock, flags);
@@ -378,9 +379,48 @@ static int pkg_temp_thermal_platform_thermal_notify(__u64 msr_val)
schedule_delayed_work_on(cpu,
&per_cpu(pkg_temp_thermal_threshold_work, cpu),
msecs_to_jiffies(notify_delay_ms));
+}
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+static struct swork_event notify_work;
+
+static int thermal_notify_work_init(void)
+{
+ int err;
+
+ err = swork_get();
+ if (!err)
+ return err;
+
+ INIT_SWORK(¬ify_work, platform_thermal_notify_work);
return 0;
}
+static void thermal_notify_work_cleanup(void)
+{
+ swork_put();
+}
+
+static int pkg_temp_thermal_platform_thermal_notify(__u64 msr_val)
+{
+ swork_queue(¬ify_work);
+ return 0;
+}
+
+#else /* !CONFIG_PREEMPT_RT_FULL */
+
+static int thermal_notify_work_init(void) { return 0; }
+
+static int thermal_notify_work_cleanup(void) { }
+
+static int pkg_temp_thermal_platform_thermal_notify(__u64 msr_val)
+{
+ platform_thermal_notify_work(NULL);
+
+ return 0;
+}
+#endif /* CONFIG_PREEMPT_RT_FULL */
+
static int find_siblings_cpu(int cpu)
{
int i;
@@ -584,6 +624,9 @@ static int __init pkg_temp_thermal_init(void)
if (!x86_match_cpu(pkg_temp_thermal_ids))
return -ENODEV;
+ if (!thermal_notify_work_init())
+ return -ENODEV;
+
spin_lock_init(&pkg_work_lock);
platform_thermal_package_notify =
pkg_temp_thermal_platform_thermal_notify;
@@ -594,6 +637,7 @@ static int __init pkg_temp_thermal_init(void)
for_each_online_cpu(i)
if (get_core_online(i))
goto err_ret;
+
__register_hotcpu_notifier(&pkg_temp_thermal_notifier);
cpu_notifier_register_done();
@@ -608,7 +652,7 @@ static int __init pkg_temp_thermal_init(void)
kfree(pkg_work_scheduled);
platform_thermal_package_notify = NULL;
platform_thermal_package_rate_control = NULL;
-
+ thermal_notify_work_cleanup();
return -ENODEV;
}
@@ -633,6 +677,7 @@ static void __exit pkg_temp_thermal_exit(void)
mutex_unlock(&phy_dev_list_mutex);
platform_thermal_package_notify = NULL;
platform_thermal_package_rate_control = NULL;
+ thermal_notify_work_cleanup();
for_each_online_cpu(i)
cancel_delayed_work_sync(
&per_cpu(pkg_temp_thermal_threshold_work, i));
--
2.1.4
--
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