linux/kernel/power/process.c
Nigel Cunningham ff39593ad0 [PATCH] swsusp: thaw userspace and kernel space separately
Modify process thawing so that we can thaw kernel space without thawing
userspace, and thaw kernelspace first.  This will be useful in later
patches, where I intend to get swsusp thawing kernel threads only before
seeking to free memory.

Signed-off-by: Nigel Cunningham <nigel@suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:28 -08:00

185 lines
4.2 KiB
C

/*
* drivers/power/process.c - Functions for starting/stopping processes on
* suspend transitions.
*
* Originally from swsusp.
*/
#undef DEBUG
#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/module.h>
#include <linux/syscalls.h>
#include <linux/freezer.h>
/*
* Timeout for stopping processes
*/
#define TIMEOUT (20 * HZ)
static inline int freezeable(struct task_struct * p)
{
if ((p == current) ||
(p->flags & PF_NOFREEZE) ||
(p->exit_state == EXIT_ZOMBIE) ||
(p->exit_state == EXIT_DEAD) ||
(p->state == TASK_STOPPED))
return 0;
return 1;
}
/* Refrigerator is place where frozen processes are stored :-). */
void refrigerator(void)
{
/* Hmm, should we be allowed to suspend when there are realtime
processes around? */
long save;
save = current->state;
pr_debug("%s entered refrigerator\n", current->comm);
frozen_process(current);
spin_lock_irq(&current->sighand->siglock);
recalc_sigpending(); /* We sent fake signal, clean it up */
spin_unlock_irq(&current->sighand->siglock);
while (frozen(current)) {
current->state = TASK_UNINTERRUPTIBLE;
schedule();
}
pr_debug("%s left refrigerator\n", current->comm);
current->state = save;
}
static inline void freeze_process(struct task_struct *p)
{
unsigned long flags;
if (!freezing(p)) {
freeze(p);
spin_lock_irqsave(&p->sighand->siglock, flags);
signal_wake_up(p, 0);
spin_unlock_irqrestore(&p->sighand->siglock, flags);
}
}
static void cancel_freezing(struct task_struct *p)
{
unsigned long flags;
if (freezing(p)) {
pr_debug(" clean up: %s\n", p->comm);
do_not_freeze(p);
spin_lock_irqsave(&p->sighand->siglock, flags);
recalc_sigpending_tsk(p);
spin_unlock_irqrestore(&p->sighand->siglock, flags);
}
}
/* 0 = success, else # of processes that we failed to stop */
int freeze_processes(void)
{
int todo, nr_user, user_frozen;
unsigned long start_time;
struct task_struct *g, *p;
printk("Stopping tasks... ");
start_time = jiffies;
user_frozen = 0;
do {
nr_user = todo = 0;
read_lock(&tasklist_lock);
do_each_thread(g, p) {
if (!freezeable(p))
continue;
if (frozen(p))
continue;
if (p->state == TASK_TRACED && frozen(p->parent)) {
cancel_freezing(p);
continue;
}
if (p->mm && !(p->flags & PF_BORROWED_MM)) {
/* The task is a user-space one.
* Freeze it unless there's a vfork completion
* pending
*/
if (!p->vfork_done)
freeze_process(p);
nr_user++;
} else {
/* Freeze only if the user space is frozen */
if (user_frozen)
freeze_process(p);
todo++;
}
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
todo += nr_user;
if (!user_frozen && !nr_user) {
sys_sync();
start_time = jiffies;
}
user_frozen = !nr_user;
yield(); /* Yield is okay here */
if (todo && time_after(jiffies, start_time + TIMEOUT))
break;
} while(todo);
/* This does not unfreeze processes that are already frozen
* (we have slightly ugly calling convention in that respect,
* and caller must call thaw_processes() if something fails),
* but it cleans up leftover PF_FREEZE requests.
*/
if (todo) {
printk("\n");
printk(KERN_ERR "Stopping tasks timed out "
"after %d seconds (%d tasks remaining):\n",
TIMEOUT / HZ, todo);
read_lock(&tasklist_lock);
do_each_thread(g, p) {
if (freezeable(p) && !frozen(p))
printk(KERN_ERR " %s\n", p->comm);
cancel_freezing(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
return todo;
}
printk("done.\n");
BUG_ON(in_atomic());
return 0;
}
void thaw_some_processes(int all)
{
struct task_struct *g, *p;
int pass = 0; /* Pass 0 = Kernel space, 1 = Userspace */
printk("Restarting tasks... ");
read_lock(&tasklist_lock);
do {
do_each_thread(g, p) {
/*
* is_user = 0 if kernel thread or borrowed mm,
* 1 otherwise.
*/
int is_user = !!(p->mm && !(p->flags & PF_BORROWED_MM));
if (!freezeable(p) || (is_user != pass))
continue;
if (!thaw_process(p))
printk(KERN_INFO
"Strange, %s not stopped\n", p->comm);
} while_each_thread(g, p);
pass++;
} while (pass < 2 && all);
read_unlock(&tasklist_lock);
schedule();
printk("done.\n");
}
EXPORT_SYMBOL(refrigerator);