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Subject[PATCH] Thaw userspace and kernel space separately.
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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>

diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index 266373f..294ebea 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -1,5 +1,8 @@
/* Freezer declarations */

+#define FREEZER_KERNEL_THREADS 0
+#define FREEZER_ALL_THREADS 1
+
#ifdef CONFIG_PM
/*
* Check if a process has been frozen
@@ -57,7 +60,8 @@ static inline void frozen_process(struct

extern void refrigerator(void);
extern int freeze_processes(void);
-extern void thaw_processes(void);
+#define thaw_processes() do { thaw_some_processes(FREEZER_ALL_THREADS); } while(0)
+#define thaw_kernel_threads() do { thaw_some_processes(FREEZER_KERNEL_THREADS); } while(0)

static inline int try_to_freeze(void)
{
@@ -67,6 +71,9 @@ static inline int try_to_freeze(void)
} else
return 0;
}
+
+extern void thaw_some_processes(int all);
+
#else
static inline int frozen(struct task_struct *p) { return 0; }
static inline int freezing(struct task_struct *p) { return 0; }
diff --git a/kernel/power/process.c b/kernel/power/process.c
index fedabad..4a001fe 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -153,18 +153,29 @@ int freeze_processes(void)
return 0;
}

-void thaw_processes(void)
+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_each_thread(g, p) {
- if (!freezeable(p))
- continue;
- if (!thaw_process(p))
- printk(KERN_INFO "Strange, %s not stopped\n", p->comm);
- } while_each_thread(g, p);
+ 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();

-
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