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Date: Sun, 31 May 2015 05:07:42 +0000 (GMT)
From: EunTaik Lee <eun.taik.lee@...sung.com>
To: "rjw@...ysocki.net" <rjw@...ysocki.net>,
"pavel@....cz" <pavel@....cz>,
"len.brown@...el.com" <len.brown@...el.com>,
"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH v2] suspend/resume performance improvement
When a task that calls state_store() to suspend
the device has used up most of its time slice,
suspend sometimes take too long. (User noticeable)
Suspend/resume is a system wide operation.
So, instead of depending on a userspace task's time
slice, let kworker do the work to avoid a long wait
on the runqueue.
Signed-off-by: Eun Taik Lee <eun.taik.lee@...sung.com>
---
kernel/power/main.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 90 insertions(+), 5 deletions(-)
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 86e8157..848bf2d 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -15,7 +15,7 @@
#include <linux/workqueue.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
-
+#include <linux/completion.h>
#include "power.h"
DEFINE_MUTEX(pm_mutex);
@@ -335,15 +335,46 @@ static suspend_state_t decode_state(const char *buf, size_t n)
return PM_SUSPEND_ON;
}
+static struct workqueue_struct *suspend_helper_wq;
+struct state_store_params {
+ const char *buf;
+ size_t n;
+};
+
+struct suspend_helper_data {
+ struct work_struct work;
+ struct completion done;
+ struct state_store_params params;
+ int result;
+};
+struct suspend_helper_data suspend_helper_data;
+
+static ssize_t state_store_helper(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t n);
+
static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t n)
{
+ return state_store_helper(kobj, attr, buf, n);
+}
+
+power_attr(state);
+
+static void suspend_helper(struct work_struct *work)
+{
+ struct suspend_helper_data *data = (struct suspend_helper_data *)
+ container_of(work, struct suspend_helper_data, work);
+ const char *buf = data->params.buf;
+ size_t n = data->params.n;
suspend_state_t state;
- int error;
+ int error = 0;
+
+ pr_debug("%s: start!\n", __func__);
error = pm_autosleep_lock();
if (error)
- return error;
+ goto out_nolock;
if (pm_autosleep_state() > PM_SUSPEND_ON) {
error = -EBUSY;
@@ -358,12 +389,64 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
else
error = -EINVAL;
- out:
+out:
pm_autosleep_unlock();
+
+out_nolock:
+ /* set result and notify completion */
+ data->result = error;
+ complete(&data->done);
+
+ pr_debug("%s: result = %d\n", __func__, error);
+}
+
+static ssize_t state_store_helper(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ int error;
+ int freezable = 0;
+
+ /* we don't need to freeze. so tell the freezer */
+ if (!freezer_should_skip(current)) {
+ freezable = 1;
+ freezer_do_not_count();
+ pr_debug("%s: freezer should skip me (%s:%d)\n",
+ __func__, current->comm, current->pid);
+ }
+
+ suspend_helper_data.params.buf = buf;
+ suspend_helper_data.params.n = n;
+ init_completion(&suspend_helper_data.done);
+
+ /* use kworker for suspend resume */
+ queue_work(suspend_helper_wq, &suspend_helper_data.work);
+
+ /* wait for suspend/resume work to be complete */
+ wait_for_completion(&suspend_helper_data.done);
+
+ if (freezable) {
+ /* set ourself as freezable */
+ freezer_count();
+ }
+
+ error = suspend_helper_data.result;
+ pr_debug("%s: suspend_helper returned %d\n", __func__, error);
+
return error ? error : n;
}
-power_attr(state);
+static int suspend_helper_init(void)
+{
+ suspend_helper_wq = alloc_ordered_workqueue("suspend_helper", 0);
+ if (!suspend_helper_wq)
+ return -ENOMEM;
+
+ INIT_WORK(&suspend_helper_data.work, suspend_helper);
+ init_completion(&suspend_helper_data.done);
+
+ return 0;
+}
#ifdef CONFIG_PM_SLEEP
/*
@@ -640,6 +723,8 @@ static int __init pm_init(void)
if (error)
return error;
pm_print_times_init();
+ suspend_helper_init();
+
return pm_autosleep_init();
}
--
1.9.1
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