[RFC PATCH 4/4] Container Freezer: Skip frozen cgroups during power management resume

[matthltc@us.ibm.com]

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When a system is resumed after a suspend, it will also unfreeze 
frozen cgroups. 

This patchs modifies the resume sequence to skip the tasks which 
are part of a frozen control group. 

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Cc: linux-pm@lists.linux-foundation.org
---
 kernel/power/process.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux-2.6.25-rc5-mm1/kernel/power/process.c
===================================================================
--- linux-2.6.25-rc5-mm1.orig/kernel/power/process.c
+++ linux-2.6.25-rc5-mm1/kernel/power/process.c
@@ -11,10 +11,11 @@
 #include <linux/interrupt.h>
 #include <linux/suspend.h>
 #include <linux/module.h>
 #include <linux/syscalls.h>
 #include <linux/freezer.h>
+#include <linux/cgroup_freezer.h>
 
 /* 
  * Timeout for stopping processes
  */
 #define TIMEOUT	(20 * HZ)
@@ -150,10 +151,13 @@ static void thaw_tasks(int thaw_user_spa
 			continue;
 
 		if (!p->mm == thaw_user_space)
 			continue;
 
+		if (cgroup_frozen(p))
+			continue;
+
 		thaw_process(p);
 	} while_each_thread(g, p);
 	read_unlock(&tasklist_lock);
 }
 

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