The patch titled
pm_qos_requirement might sleep
has been added to the -mm tree. Its filename is
pm_qos_requirement-might-sleep.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: pm_qos_requirement might sleep
From: John Kacur <jkacur@xxxxxxxxx>
Make PM_QOS and CPU_IDLE play nicer when run with the RT-Preempt kernel.
CPU_IDLE polls the target_value's of some of the pm_qos parameters from
the idle loop causing sleeping locking warnings. Changing the
target_value to an atomic avoids this issue.
Remove the spinlock in pm_qos_requirement by making target_value an atomic
type.
Signed-off-by: mark gross <mgross@xxxxxxxxxxxxxxx>
Signed-off-by: John Kacur <jkacur@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/pm_qos_params.c | 25 +++++++++----------------
1 file changed, 9 insertions(+), 16 deletions(-)
diff -puN kernel/pm_qos_params.c~pm_qos_requirement-might-sleep kernel/pm_qos_params.c
--- a/kernel/pm_qos_params.c~pm_qos_requirement-might-sleep
+++ a/kernel/pm_qos_params.c
@@ -43,7 +43,7 @@
#include <linux/uaccess.h>
/*
- * locking rule: all changes to target_value or requirements or notifiers lists
+ * locking rule: all changes to requirements or notifiers lists
* or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
* held, taken with _irqsave. One lock to rule them all
*/
@@ -66,7 +66,7 @@ struct pm_qos_object {
struct miscdevice pm_qos_power_miscdev;
char *name;
s32 default_value;
- s32 target_value;
+ atomic_t target_value;
s32 (*comparitor)(s32, s32);
};
@@ -77,7 +77,7 @@ static struct pm_qos_object cpu_dma_pm_q
.notifiers = &cpu_dma_lat_notifier,
.name = "cpu_dma_latency",
.default_value = 2000 * USEC_PER_SEC,
- .target_value = 2000 * USEC_PER_SEC,
+ .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
.comparitor = min_compare
};
@@ -87,7 +87,7 @@ static struct pm_qos_object network_lat_
.notifiers = &network_lat_notifier,
.name = "network_latency",
.default_value = 2000 * USEC_PER_SEC,
- .target_value = 2000 * USEC_PER_SEC,
+ .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC),
.comparitor = min_compare
};
@@ -99,7 +99,7 @@ static struct pm_qos_object network_thro
.notifiers = &network_throughput_notifier,
.name = "network_throughput",
.default_value = 0,
- .target_value = 0,
+ .target_value = ATOMIC_INIT(0),
.comparitor = max_compare
};
@@ -150,11 +150,11 @@ static void update_target(int target)
extreme_value = pm_qos_array[target]->comparitor(
extreme_value, node->value);
}
- if (pm_qos_array[target]->target_value != extreme_value) {
+ if (atomic_read(&pm_qos_array[target]->target_value) != extreme_value) {
call_notifier = 1;
- pm_qos_array[target]->target_value = extreme_value;
+ atomic_set(&pm_qos_array[target]->target_value, extreme_value);
pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
- pm_qos_array[target]->target_value);
+ atomic_read(&pm_qos_array[target]->target_value));
}
spin_unlock_irqrestore(&pm_qos_lock, flags);
@@ -193,14 +193,7 @@ static int find_pm_qos_object_by_minor(i
*/
int pm_qos_requirement(int pm_qos_class)
{
- int ret_val;
- unsigned long flags;
-
- spin_lock_irqsave(&pm_qos_lock, flags);
- ret_val = pm_qos_array[pm_qos_class]->target_value;
- spin_unlock_irqrestore(&pm_qos_lock, flags);
-
- return ret_val;
+ return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
}
EXPORT_SYMBOL_GPL(pm_qos_requirement);
_
Patches currently in -mm which might be from jkacur@xxxxxxxxx are
pm_qos_requirement-might-sleep.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
