[S390] ap: Use high-resolution timer for polling
The ap poll mechanism is converted to use a high-resolution timer for polling. This allows more specific polling. With this a new sysfs attribute is introduced to specify the polling rate in nanoseconds. Signed-off-by: Felix Beck <felix.beck@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
This commit is contained in:
parent
ad211790c0
commit
fe13723061
@ -34,13 +34,15 @@
|
||||
#include <linux/mutex.h>
|
||||
#include <asm/s390_rdev.h>
|
||||
#include <asm/reset.h>
|
||||
#include <linux/hrtimer.h>
|
||||
#include <linux/ktime.h>
|
||||
|
||||
#include "ap_bus.h"
|
||||
|
||||
/* Some prototypes. */
|
||||
static void ap_scan_bus(struct work_struct *);
|
||||
static void ap_poll_all(unsigned long);
|
||||
static void ap_poll_timeout(unsigned long);
|
||||
static enum hrtimer_restart ap_poll_timeout(struct hrtimer *);
|
||||
static int ap_poll_thread_start(void);
|
||||
static void ap_poll_thread_stop(void);
|
||||
static void ap_request_timeout(unsigned long);
|
||||
@ -80,12 +82,15 @@ static DECLARE_WORK(ap_config_work, ap_scan_bus);
|
||||
/*
|
||||
* Tasklet & timer for AP request polling.
|
||||
*/
|
||||
static struct timer_list ap_poll_timer = TIMER_INITIALIZER(ap_poll_timeout,0,0);
|
||||
static DECLARE_TASKLET(ap_tasklet, ap_poll_all, 0);
|
||||
static atomic_t ap_poll_requests = ATOMIC_INIT(0);
|
||||
static DECLARE_WAIT_QUEUE_HEAD(ap_poll_wait);
|
||||
static struct task_struct *ap_poll_kthread = NULL;
|
||||
static DEFINE_MUTEX(ap_poll_thread_mutex);
|
||||
static struct hrtimer ap_poll_timer;
|
||||
/* In LPAR poll with 4kHz frequency. Poll every 250000 nanoseconds.
|
||||
* If z/VM change to 1500000 nanoseconds to adjust to z/VM polling.*/
|
||||
static unsigned long long poll_timeout = 250000;
|
||||
|
||||
/**
|
||||
* ap_intructions_available() - Test if AP instructions are available.
|
||||
@ -636,11 +641,39 @@ static ssize_t ap_poll_thread_store(struct bus_type *bus,
|
||||
|
||||
static BUS_ATTR(poll_thread, 0644, ap_poll_thread_show, ap_poll_thread_store);
|
||||
|
||||
static ssize_t poll_timeout_show(struct bus_type *bus, char *buf)
|
||||
{
|
||||
return snprintf(buf, PAGE_SIZE, "%llu\n", poll_timeout);
|
||||
}
|
||||
|
||||
static ssize_t poll_timeout_store(struct bus_type *bus, const char *buf,
|
||||
size_t count)
|
||||
{
|
||||
unsigned long long time;
|
||||
ktime_t hr_time;
|
||||
|
||||
/* 120 seconds = maximum poll interval */
|
||||
if (sscanf(buf, "%llu\n", &time) != 1 || time < 1 || time > 120000000000)
|
||||
return -EINVAL;
|
||||
poll_timeout = time;
|
||||
hr_time = ktime_set(0, poll_timeout);
|
||||
|
||||
if (!hrtimer_is_queued(&ap_poll_timer) ||
|
||||
!hrtimer_forward(&ap_poll_timer, ap_poll_timer.expires, hr_time)) {
|
||||
ap_poll_timer.expires = hr_time;
|
||||
hrtimer_start(&ap_poll_timer, hr_time, HRTIMER_MODE_ABS);
|
||||
}
|
||||
return count;
|
||||
}
|
||||
|
||||
static BUS_ATTR(poll_timeout, 0644, poll_timeout_show, poll_timeout_store);
|
||||
|
||||
static struct bus_attribute *const ap_bus_attrs[] = {
|
||||
&bus_attr_ap_domain,
|
||||
&bus_attr_config_time,
|
||||
&bus_attr_poll_thread,
|
||||
NULL
|
||||
&bus_attr_poll_timeout,
|
||||
NULL,
|
||||
};
|
||||
|
||||
/**
|
||||
@ -895,9 +928,10 @@ ap_config_timeout(unsigned long ptr)
|
||||
*/
|
||||
static inline void ap_schedule_poll_timer(void)
|
||||
{
|
||||
if (timer_pending(&ap_poll_timer))
|
||||
if (hrtimer_is_queued(&ap_poll_timer))
|
||||
return;
|
||||
mod_timer(&ap_poll_timer, jiffies + AP_POLL_TIME);
|
||||
hrtimer_start(&ap_poll_timer, ktime_set(0, poll_timeout),
|
||||
HRTIMER_MODE_ABS);
|
||||
}
|
||||
|
||||
/**
|
||||
@ -1115,13 +1149,14 @@ EXPORT_SYMBOL(ap_cancel_message);
|
||||
|
||||
/**
|
||||
* ap_poll_timeout(): AP receive polling for finished AP requests.
|
||||
* @unused: Unused variable.
|
||||
* @unused: Unused pointer.
|
||||
*
|
||||
* Schedules the AP tasklet.
|
||||
* Schedules the AP tasklet using a high resolution timer.
|
||||
*/
|
||||
static void ap_poll_timeout(unsigned long unused)
|
||||
static enum hrtimer_restart ap_poll_timeout(struct hrtimer *unused)
|
||||
{
|
||||
tasklet_schedule(&ap_tasklet);
|
||||
return HRTIMER_NORESTART;
|
||||
}
|
||||
|
||||
/**
|
||||
@ -1344,6 +1379,14 @@ int __init ap_module_init(void)
|
||||
ap_config_timer.expires = jiffies + ap_config_time * HZ;
|
||||
add_timer(&ap_config_timer);
|
||||
|
||||
/* Setup the high resultion poll timer.
|
||||
* If we are running under z/VM adjust polling to z/VM polling rate.
|
||||
*/
|
||||
if (MACHINE_IS_VM)
|
||||
poll_timeout = 1500000;
|
||||
hrtimer_init(&ap_poll_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
|
||||
ap_poll_timer.function = ap_poll_timeout;
|
||||
|
||||
/* Start the low priority AP bus poll thread. */
|
||||
if (ap_thread_flag) {
|
||||
rc = ap_poll_thread_start();
|
||||
@ -1355,7 +1398,7 @@ int __init ap_module_init(void)
|
||||
|
||||
out_work:
|
||||
del_timer_sync(&ap_config_timer);
|
||||
del_timer_sync(&ap_poll_timer);
|
||||
hrtimer_cancel(&ap_poll_timer);
|
||||
destroy_workqueue(ap_work_queue);
|
||||
out_root:
|
||||
s390_root_dev_unregister(ap_root_device);
|
||||
@ -1386,7 +1429,7 @@ void ap_module_exit(void)
|
||||
ap_reset_domain();
|
||||
ap_poll_thread_stop();
|
||||
del_timer_sync(&ap_config_timer);
|
||||
del_timer_sync(&ap_poll_timer);
|
||||
hrtimer_cancel(&ap_poll_timer);
|
||||
destroy_workqueue(ap_work_queue);
|
||||
tasklet_kill(&ap_tasklet);
|
||||
s390_root_dev_unregister(ap_root_device);
|
||||
|
Loading…
Reference in New Issue
Block a user