container freezer: add TIF_FREEZE flag to all architectures

This patch series introduces a cgroup subsystem that utilizes the swsusp
freezer to freeze a group of tasks.  It's immediately useful for batch job
management scripts.  It should also be useful in the future for
implementing container checkpoint/restart.

The freezer subsystem in the container filesystem defines a cgroup file
named freezer.state.  Reading freezer.state will return the current state
of the cgroup.  Writing "FROZEN" to the state file will freeze all tasks
in the cgroup.  Subsequently writing "RUNNING" will unfreeze the tasks in
the cgroup.

* Examples of usage :

   # mkdir /containers/freezer
   # mount -t cgroup -ofreezer freezer  /containers
   # mkdir /containers/0
   # echo $some_pid > /containers/0/tasks

to get status of the freezer subsystem :

   # cat /containers/0/freezer.state
   RUNNING

to freeze all tasks in the container :

   # echo FROZEN > /containers/0/freezer.state
   # cat /containers/0/freezer.state
   FREEZING
   # cat /containers/0/freezer.state
   FROZEN

to unfreeze all tasks in the container :

   # echo RUNNING > /containers/0/freezer.state
   # cat /containers/0/freezer.state
   RUNNING

This patch:

The first step in making the refrigerator() available to all
architectures, even for those without power management.

The purpose of such a change is to be able to use the refrigerator() in a
new control group subsystem which will implement a control group freezer.

[akpm@linux-foundation.org: fix sparc]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Pavel Machek <pavel@suse.cz>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Nigel Cunningham <nigel@tuxonice.net>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 4 insertions, 0 deletions

diff --git a/arch/sparc/include/asm/thread_info_32.h b/arch/sparc/include/asm/thread_info_32.h
index 29899fd5b1b2..80fe547c3f45 100644
--- a/arch/sparc/include/asm/thread_info_32.h
+++ b/arch/sparc/include/asm/thread_info_32.h
@@ -135,6 +135,7 @@ BTFIXUPDEF_CALL(void, free_thread_info, struct thread_info *)
 #define TIF_POLLING_NRFLAG      9       /* true if poll_idle() is polling
                                          * TIF_NEED_RESCHED */
 #define TIF_MEMDIE              10
+#define TIF_FREEZE              11      /* is freezing for suspend */
 
 /* as above, but as bit values */
 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
@@ -148,6 +149,7 @@ BTFIXUPDEF_CALL(void, free_thread_info, struct thread_info *)
 #define _TIF_DO_NOTIFY_RESUME_MASK      (_TIF_NOTIFY_RESUME | \
                                          _TIF_SIGPENDING | \
                                          _TIF_RESTORE_SIGMASK)
+#define _TIF_FREEZE             (1<<TIF_FREEZE)
 
 #endif /* __KERNEL__ */
 
diff --git a/arch/sparc/include/asm/thread_info_64.h b/arch/sparc/include/asm/thread_info_64.h
index c0a737d7292c..639ac805448a 100644
--- a/arch/sparc/include/asm/thread_info_64.h
+++ b/arch/sparc/include/asm/thread_info_64.h
@@ -237,6 +237,7 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define TIF_ABI_PENDING         12
 #define TIF_MEMDIE              13
 #define TIF_POLLING_NRFLAG      14
+#define TIF_FREEZE              15      /* is freezing for suspend */
 
 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
@@ -249,6 +250,7 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 #define _TIF_ABI_PENDING        (1<<TIF_ABI_PENDING)
 #define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
+#define _TIF_FREEZE             (1<<TIF_FREEZE)
 
 #define _TIF_USER_WORK_MASK     ((0xff << TI_FLAG_WSAVED_SHIFT) | \
                                  _TIF_DO_NOTIFY_RESUME_MASK | \