![Ingo Molnar](/assets/img/avatar_default.png)
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
242 lines
5.5 KiB
C
242 lines
5.5 KiB
C
/*
|
|
* drivers/power/process.c - Functions for starting/stopping processes on
|
|
* suspend transitions.
|
|
*
|
|
* Originally from swsusp.
|
|
*/
|
|
|
|
|
|
#undef DEBUG
|
|
|
|
#include <linux/interrupt.h>
|
|
#include <linux/oom.h>
|
|
#include <linux/suspend.h>
|
|
#include <linux/module.h>
|
|
#include <linux/sched/debug.h>
|
|
#include <linux/sched/task.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/freezer.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/kmod.h>
|
|
#include <trace/events/power.h>
|
|
|
|
/*
|
|
* Timeout for stopping processes
|
|
*/
|
|
unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC;
|
|
|
|
static int try_to_freeze_tasks(bool user_only)
|
|
{
|
|
struct task_struct *g, *p;
|
|
unsigned long end_time;
|
|
unsigned int todo;
|
|
bool wq_busy = false;
|
|
ktime_t start, end, elapsed;
|
|
unsigned int elapsed_msecs;
|
|
bool wakeup = false;
|
|
int sleep_usecs = USEC_PER_MSEC;
|
|
|
|
start = ktime_get_boottime();
|
|
|
|
end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs);
|
|
|
|
if (!user_only)
|
|
freeze_workqueues_begin();
|
|
|
|
while (true) {
|
|
todo = 0;
|
|
read_lock(&tasklist_lock);
|
|
for_each_process_thread(g, p) {
|
|
if (p == current || !freeze_task(p))
|
|
continue;
|
|
|
|
if (!freezer_should_skip(p))
|
|
todo++;
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
|
|
if (!user_only) {
|
|
wq_busy = freeze_workqueues_busy();
|
|
todo += wq_busy;
|
|
}
|
|
|
|
if (!todo || time_after(jiffies, end_time))
|
|
break;
|
|
|
|
if (pm_wakeup_pending()) {
|
|
wakeup = true;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* We need to retry, but first give the freezing tasks some
|
|
* time to enter the refrigerator. Start with an initial
|
|
* 1 ms sleep followed by exponential backoff until 8 ms.
|
|
*/
|
|
usleep_range(sleep_usecs / 2, sleep_usecs);
|
|
if (sleep_usecs < 8 * USEC_PER_MSEC)
|
|
sleep_usecs *= 2;
|
|
}
|
|
|
|
end = ktime_get_boottime();
|
|
elapsed = ktime_sub(end, start);
|
|
elapsed_msecs = ktime_to_ms(elapsed);
|
|
|
|
if (todo) {
|
|
pr_cont("\n");
|
|
pr_err("Freezing of tasks %s after %d.%03d seconds "
|
|
"(%d tasks refusing to freeze, wq_busy=%d):\n",
|
|
wakeup ? "aborted" : "failed",
|
|
elapsed_msecs / 1000, elapsed_msecs % 1000,
|
|
todo - wq_busy, wq_busy);
|
|
|
|
if (wq_busy)
|
|
show_workqueue_state();
|
|
|
|
if (!wakeup) {
|
|
read_lock(&tasklist_lock);
|
|
for_each_process_thread(g, p) {
|
|
if (p != current && !freezer_should_skip(p)
|
|
&& freezing(p) && !frozen(p))
|
|
sched_show_task(p);
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
} else {
|
|
pr_cont("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000,
|
|
elapsed_msecs % 1000);
|
|
}
|
|
|
|
return todo ? -EBUSY : 0;
|
|
}
|
|
|
|
/**
|
|
* freeze_processes - Signal user space processes to enter the refrigerator.
|
|
* The current thread will not be frozen. The same process that calls
|
|
* freeze_processes must later call thaw_processes.
|
|
*
|
|
* On success, returns 0. On failure, -errno and system is fully thawed.
|
|
*/
|
|
int freeze_processes(void)
|
|
{
|
|
int error;
|
|
|
|
error = __usermodehelper_disable(UMH_FREEZING);
|
|
if (error)
|
|
return error;
|
|
|
|
/* Make sure this task doesn't get frozen */
|
|
current->flags |= PF_SUSPEND_TASK;
|
|
|
|
if (!pm_freezing)
|
|
atomic_inc(&system_freezing_cnt);
|
|
|
|
pm_wakeup_clear();
|
|
pr_info("Freezing user space processes ... ");
|
|
pm_freezing = true;
|
|
error = try_to_freeze_tasks(true);
|
|
if (!error) {
|
|
__usermodehelper_set_disable_depth(UMH_DISABLED);
|
|
pr_cont("done.");
|
|
}
|
|
pr_cont("\n");
|
|
BUG_ON(in_atomic());
|
|
|
|
/*
|
|
* Now that the whole userspace is frozen we need to disbale
|
|
* the OOM killer to disallow any further interference with
|
|
* killable tasks. There is no guarantee oom victims will
|
|
* ever reach a point they go away we have to wait with a timeout.
|
|
*/
|
|
if (!error && !oom_killer_disable(msecs_to_jiffies(freeze_timeout_msecs)))
|
|
error = -EBUSY;
|
|
|
|
if (error)
|
|
thaw_processes();
|
|
return error;
|
|
}
|
|
|
|
/**
|
|
* freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
|
|
*
|
|
* On success, returns 0. On failure, -errno and only the kernel threads are
|
|
* thawed, so as to give a chance to the caller to do additional cleanups
|
|
* (if any) before thawing the userspace tasks. So, it is the responsibility
|
|
* of the caller to thaw the userspace tasks, when the time is right.
|
|
*/
|
|
int freeze_kernel_threads(void)
|
|
{
|
|
int error;
|
|
|
|
pr_info("Freezing remaining freezable tasks ... ");
|
|
|
|
pm_nosig_freezing = true;
|
|
error = try_to_freeze_tasks(false);
|
|
if (!error)
|
|
pr_cont("done.");
|
|
|
|
pr_cont("\n");
|
|
BUG_ON(in_atomic());
|
|
|
|
if (error)
|
|
thaw_kernel_threads();
|
|
return error;
|
|
}
|
|
|
|
void thaw_processes(void)
|
|
{
|
|
struct task_struct *g, *p;
|
|
struct task_struct *curr = current;
|
|
|
|
trace_suspend_resume(TPS("thaw_processes"), 0, true);
|
|
if (pm_freezing)
|
|
atomic_dec(&system_freezing_cnt);
|
|
pm_freezing = false;
|
|
pm_nosig_freezing = false;
|
|
|
|
oom_killer_enable();
|
|
|
|
pr_info("Restarting tasks ... ");
|
|
|
|
__usermodehelper_set_disable_depth(UMH_FREEZING);
|
|
thaw_workqueues();
|
|
|
|
read_lock(&tasklist_lock);
|
|
for_each_process_thread(g, p) {
|
|
/* No other threads should have PF_SUSPEND_TASK set */
|
|
WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK));
|
|
__thaw_task(p);
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
|
|
WARN_ON(!(curr->flags & PF_SUSPEND_TASK));
|
|
curr->flags &= ~PF_SUSPEND_TASK;
|
|
|
|
usermodehelper_enable();
|
|
|
|
schedule();
|
|
pr_cont("done.\n");
|
|
trace_suspend_resume(TPS("thaw_processes"), 0, false);
|
|
}
|
|
|
|
void thaw_kernel_threads(void)
|
|
{
|
|
struct task_struct *g, *p;
|
|
|
|
pm_nosig_freezing = false;
|
|
pr_info("Restarting kernel threads ... ");
|
|
|
|
thaw_workqueues();
|
|
|
|
read_lock(&tasklist_lock);
|
|
for_each_process_thread(g, p) {
|
|
if (p->flags & (PF_KTHREAD | PF_WQ_WORKER))
|
|
__thaw_task(p);
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
|
|
schedule();
|
|
pr_cont("done.\n");
|
|
}
|