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authorRafael J. Wysocki <rjw@sisk.pl>2006-12-06 20:34:40 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-07 08:39:28 -0800
commit11b2ce2ba90f801e2a5ebba4e6b7da72d87f2b13 (patch)
treee7477edb04a15a3128523877558e1eb8694adbc9
parenta9b6f562f14dc28fb4b2415f0f275cede0abe9b5 (diff)
[PATCH] swsusp: Untangle freeze_processes
Move the loop from freeze_processes() to a separate function and call it independently for user space processes and kernel threads so that the order of freezing tasks is clearly visible. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@suspend2.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--kernel/power/process.c84
1 files changed, 54 insertions, 30 deletions
diff --git a/kernel/power/process.c b/kernel/power/process.c
index fd0ebb942f5..99eeb119b06 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -86,24 +86,23 @@ static inline int is_user_space(struct task_struct *p)
return p->mm && !(p->flags & PF_BORROWED_MM);
}
-/* 0 = success, else # of processes that we failed to stop */
-int freeze_processes(void)
+static unsigned int try_to_freeze_tasks(int freeze_user_space)
{
- int todo, nr_user, user_frozen;
- unsigned long start_time;
struct task_struct *g, *p;
+ unsigned long end_time;
+ unsigned int todo;
- printk("Stopping tasks... ");
- start_time = jiffies;
- user_frozen = 0;
+ end_time = jiffies + TIMEOUT;
do {
- nr_user = todo = 0;
+ 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) ||
p->parent->state == TASK_STOPPED)) {
@@ -111,51 +110,76 @@ int freeze_processes(void)
continue;
}
if (is_user_space(p)) {
+ if (!freeze_user_space)
+ continue;
+
/* Freeze the task unless there is 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++;
+ if (freeze_user_space)
+ continue;
+
+ 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))
+ if (todo && time_after(jiffies, end_time))
break;
- } while(todo);
+ } 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) {
+ /* 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.
+ */
printk("\n");
- printk(KERN_ERR "Stopping tasks timed out "
- "after %d seconds (%d tasks remaining):\n",
- TIMEOUT / HZ, todo);
+ printk(KERN_ERR "Stopping %s timed out after %d seconds "
+ "(%d tasks refusing to freeze):\n",
+ freeze_user_space ? "user space processes" :
+ "kernel threads",
+ TIMEOUT / HZ, todo);
read_lock(&tasklist_lock);
do_each_thread(g, p) {
+ if (is_user_space(p) == !freeze_user_space)
+ continue;
+
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;
}
+ return todo;
+}
+
+/**
+ * freeze_processes - tell processes to enter the refrigerator
+ *
+ * Returns 0 on success, or the number of processes that didn't freeze,
+ * although they were told to.
+ */
+int freeze_processes(void)
+{
+ unsigned int nr_unfrozen;
+
+ printk("Stopping tasks ... ");
+ nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE);
+ if (nr_unfrozen)
+ return nr_unfrozen;
+
+ sys_sync();
+ nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS);
+ if (nr_unfrozen)
+ return nr_unfrozen;
+
printk("done.\n");
BUG_ON(in_atomic());
return 0;