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Message-Id: <1460961854-3449-4-git-send-email-bill.huey@gmail.com>
Date: Sun, 17 Apr 2016 23:44:05 -0700
From: "Bill Huey (hui)" <bill.huey@...il.com>
To: Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Steven Rostedt <rostedt@...dmis.org>,
Alessandro Zummo <a.zummo@...ertech.it>,
linux-kernel@...r.kernel.org
Cc: luca abeni <luca.abeni@...tn.it>, Juri Lelli <juri.lelli@....com>,
Mike Galbraith <umgwanakikbuti@...il.com>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH RFC v2 03/12] Add cyclic support to rtc-dev.c
wait-queue changes to rtc_dev_read so that it can support overrun count
reporting when multiple threads are blocked against a single wait object.
ioctl() additions to allow for those calling it to admit the thread into
the cyclic scheduler.
Signed-off-by: Bill Huey (hui) <bill.huey@...il.com>
---
drivers/rtc/rtc-dev.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 167 insertions(+)
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index a6d9434..82c5cff 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -18,6 +18,15 @@
#include <linux/sched.h>
#include "rtc-core.h"
+#ifdef CONFIG_RTC_CYCLIC
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#include <../kernel/sched/sched.h>
+#include <../kernel/sched/cyclic.h>
+//#include <../kernel/sched/cyclic_rt.h>
+#endif
+
static dev_t rtc_devt;
#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
@@ -29,6 +38,10 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
struct rtc_device, char_dev);
const struct rtc_class_ops *ops = rtc->ops;
+#ifdef CONFIG_RTC_CYCLIC
+ reset_rt_overrun();
+#endif
+
if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
return -EBUSY;
@@ -153,13 +166,26 @@ rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
struct rtc_device *rtc = file->private_data;
+#ifdef CONFIG_RTC_CYCLIC
+ DEFINE_WAIT_FUNC(wait, single_default_wake_function);
+#else
DECLARE_WAITQUEUE(wait, current);
+#endif
unsigned long data;
+#ifdef CONFIG_RTC_CYCLIC
+ unsigned long flags;
+ int wake = 0, block = 0;
+#endif
ssize_t ret;
if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
return -EINVAL;
+#ifdef CONFIG_RTC_CYCLIC
+ if (rt_overrun_task_yield(current))
+ goto yield;
+printk("%s: 0 color = %d \n", __func__, current->rt.rt_overrun.color);
+#endif
add_wait_queue(&rtc->irq_queue, &wait);
do {
__set_current_state(TASK_INTERRUPTIBLE);
@@ -169,23 +195,65 @@ rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
rtc->irq_data = 0;
spin_unlock_irq(&rtc->irq_lock);
+#ifdef CONFIG_RTC_CYCLIC
+if (block) {
+ block = 0;
+ if (wake) {
+ printk("%s: wake \n", __func__);
+ wake = 0;
+ } else {
+ printk("%s: ~wake \n", __func__);
+ }
+}
+#endif
if (data != 0) {
+#ifdef CONFIG_RTC_CYCLIC
+ /* overrun reporting */
+ raw_spin_lock_irqsave(&rt_overrun_lock, flags);
+ if (_on_rt_overrun_admitted(current)) {
+ /* pass back to userspace */
+ data = rt_task_count(current);
+ rt_task_count(current) = 0;
+ }
+ raw_spin_unlock_irqrestore(&rt_overrun_lock, flags);
ret = 0;
+printk("%s: 1 color = %d \n", __func__, current->rt.rt_overrun.color);
break;
}
+#else
+ ret = 0;
+ break;
+ }
+#endif
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
+#ifdef CONFIG_RTC_CYCLIC
+printk("%s: 2 color = %d \n", __func__, current->rt.rt_overrun.color);
+#endif
break;
}
if (signal_pending(current)) {
+#ifdef CONFIG_RTC_CYCLIC
+printk("%s: 3 color = %d \n", __func__, current->rt.rt_overrun.color);
+#endif
ret = -ERESTARTSYS;
break;
}
+#ifdef CONFIG_RTC_CYCLIC
+ block = 1;
+#endif
schedule();
+#ifdef CONFIG_RTC_CYCLIC
+ /* debugging */
+ wake = 1;
+#endif
} while (1);
set_current_state(TASK_RUNNING);
remove_wait_queue(&rtc->irq_queue, &wait);
+#ifdef CONFIG_RTC_CYCLIC
+ret:
+#endif
if (ret == 0) {
/* Check for any data updates */
if (rtc->ops->read_callback)
@@ -201,6 +269,29 @@ rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
sizeof(unsigned long);
}
return ret;
+
+#ifdef CONFIG_RTC_CYCLIC
+yield:
+
+ spin_lock_irq(&rtc->irq_lock);
+ data = rtc->irq_data;
+ rtc->irq_data = 0;
+ spin_unlock_irq(&rtc->irq_lock);
+
+ raw_spin_lock_irqsave(&rt_overrun_lock, flags);
+ if (_on_rt_overrun_admitted(current)) {
+ /* pass back to userspace */
+ data = rt_task_count(current);
+ rt_task_count(current) = 0;
+ }
+ else {
+ }
+
+ raw_spin_unlock_irqrestore(&rt_overrun_lock, flags);
+ ret = 0;
+
+ goto ret;
+#endif
}
static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
@@ -215,6 +306,56 @@ static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
}
+#ifdef CONFIG_RTC_CYCLIC
+extern asmlinkage __visible void __sched notrace preempt_schedule(void);
+
+/* yield behavior * /
+int rt_overrun_task_yield_block(struct task_struct *p)
+{
+ struct rq *rq = task_rq(p);
+ unsigned int block = 1;
+
+ if (test_case)
+ else
+ return 1;
+
+ if (rt_overrun_task_is_best_effort(p)) {
+ // assert that it should be on the rq
+ // move to the end, let pick_next_task_rt() deal with the next runnable task
+ requeue_task_rt2(rq, p, false);
+
+ //clear_overrun_log();
+
+ if (_cond_resched()) {
+ // we reschedule here
+ }
+
+ block = 0;
+ }
+
+ return block;
+} */
+
+int test_admit(u64 slots)
+{
+ /* Only allow the current task to be admitted for now
+ * and allow for /proc to show the slot pattern
+ * in a global fashion */
+ return rt_overrun_task_admit(current, slots);
+}
+
+int test_yield(u64 slots)
+{
+ rt_task_yield(current) = slots;
+ return 0;
+}
+
+void test_replenish(void)
+{
+ rt_overrun_task_replenish(current);
+}
+#endif
+
static long rtc_dev_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
@@ -223,6 +364,9 @@ static long rtc_dev_ioctl(struct file *file,
const struct rtc_class_ops *ops = rtc->ops;
struct rtc_time tm;
struct rtc_wkalrm alarm;
+#ifdef CONFIG_RTC_CYCLIC
+ u64 slots;
+#endif
void __user *uarg = (void __user *) arg;
err = mutex_lock_interruptible(&rtc->ops_lock);
@@ -250,6 +394,12 @@ static long rtc_dev_ioctl(struct file *file,
!capable(CAP_SYS_RESOURCE))
err = -EACCES;
break;
+#ifdef CONFIG_RTC_CYCLIC
+ case RTC_OV_REPLEN:
+ test_replenish();
+ err = -EACCES;
+ break;
+#endif
}
if (err)
@@ -380,7 +530,21 @@ static long rtc_dev_ioctl(struct file *file,
case RTC_IRQP_READ:
err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
break;
+#ifdef CONFIG_RTC_CYCLIC
+ case RTC_OV_YIELD:
+ mutex_unlock(&rtc->ops_lock);
+ if (copy_from_user(&slots, uarg, sizeof(u64)))
+ return -EFAULT;
+
+ return test_yield(slots);
+
+ case RTC_OV_ADMIT:
+ mutex_unlock(&rtc->ops_lock);
+ if (copy_from_user(&slots, uarg, sizeof(u64)))
+ return -EFAULT;
+ return test_admit(slots);
+#endif
case RTC_WKALM_SET:
mutex_unlock(&rtc->ops_lock);
if (copy_from_user(&alarm, uarg, sizeof(alarm)))
@@ -424,6 +588,9 @@ static int rtc_dev_release(struct inode *inode, struct file *file)
{
struct rtc_device *rtc = file->private_data;
+#ifdef CONFIG_RTC_CYCLIC
+ rt_overrun_entries_delete_all(rtc);
+#endif
/* We shut down the repeating IRQs that userspace enabled,
* since nothing is listening to them.
* - Update (UIE) ... currently only managed through ioctls
--
2.5.0
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