lkml.org 
[lkml]   [2019]   [Nov]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH RFC 1/3] cpuidle: Replace use_deepest_state flag by use_latency
Date
We want to specify a latency constraint when choosing an idle state at
play_idle time. Instead of duplicating the information in the
structure or propagate the latency in the call stack, change the
use_deepest_state by use_latency to introduce this constraint.

A zero latency constraint means "do not use the deepest idle state
path" as the 'use_deepest_state' boolean was used in the
cpuidle_idle_call.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/cpuidle/cpuidle.c | 6 +++---
include/linux/cpuidle.h | 6 +++---
kernel/sched/idle.c | 6 +++---
3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 44ae39f2b47a..f68a6c9e8482 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -100,19 +100,19 @@ static int find_deepest_state(struct cpuidle_driver *drv,

/**
* cpuidle_use_deepest_state - Set/clear governor override flag.
- * @enable: New value of the flag.
+ * @latency: A latency constraint
*
* Set/unset the current CPU to use the deepest idle state (override governors
* going forward if set).
*/
-void cpuidle_use_deepest_state(bool enable)
+void cpuidle_use_latency(unsigned int latency)
{
struct cpuidle_device *dev;

preempt_disable();
dev = cpuidle_get_device();
if (dev)
- dev->use_deepest_state = enable;
+ dev->use_latency = latency;
preempt_enable();
}

diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index d23a3b1ddcf6..32018704f4ea 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -83,8 +83,8 @@ struct cpuidle_driver_kobj;
struct cpuidle_device {
unsigned int registered:1;
unsigned int enabled:1;
- unsigned int use_deepest_state:1;
unsigned int poll_time_limit:1;
+ unsigned int use_latency;
unsigned int cpu;
ktime_t next_hrtimer;

@@ -210,7 +210,7 @@ extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev);
extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
struct cpuidle_device *dev);
-extern void cpuidle_use_deepest_state(bool enable);
+extern void cpuidle_use_latency(unsigned int latency);
#else
static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
@@ -218,7 +218,7 @@ static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
{return -ENODEV; }
-static inline void cpuidle_use_deepest_state(bool enable)
+static inline void cpuidle_use_latency(unsigned int latency)
{
}
#endif
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 8dad5aa600ea..00e064d3dfe1 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -165,7 +165,7 @@ static void cpuidle_idle_call(void)
* until a proper wakeup interrupt happens.
*/

- if (idle_should_enter_s2idle() || dev->use_deepest_state) {
+ if (idle_should_enter_s2idle() || dev->use_latency) {
if (idle_should_enter_s2idle()) {
rcu_idle_enter();

@@ -328,7 +328,7 @@ void play_idle(unsigned long duration_us)
rcu_sleep_check();
preempt_disable();
current->flags |= PF_IDLE;
- cpuidle_use_deepest_state(true);
+ cpuidle_use_latency(1);

it.done = 0;
hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
@@ -339,7 +339,7 @@ void play_idle(unsigned long duration_us)
while (!READ_ONCE(it.done))
do_idle();

- cpuidle_use_deepest_state(false);
+ cpuidle_use_latency(0);
current->flags &= ~PF_IDLE;

preempt_fold_need_resched();
--
2.17.1
\
 
 \ /
  Last update: 2019-11-13 19:55    [W:0.049 / U:2.920 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site