make refrigerator cold

By marking it cold, then the code path in kernel thread usage of try_to_freeze() that is normally used be selected.

Don't think it matters that much for performance but the concordance of this patch struck me as humorous.

Signed-off-by Stephen Hemminger <[email protected]>

include/linux/freezer.h +1 -1

@@ -47,7 +47,7 @@ static inline bool should_send_signal(st
 /* Takes and releases task alloc lock using task_lock() */
 extern int thaw_process(struct task_struct *p);
 
-extern void refrigerator(void);
+extern void refrigerator(void) __cold;
 extern int freeze_processes(void);
 extern void thaw_processes(void);

Quoted 3 lines · Stephen Hemminger

By marking it cold, then the code path in kernel thread usage of try_to_freeze() that is normally used be selected.

Quoted 3 lines · Stephen Hemminger

By marking it cold, then the code path in kernel thread usage of try_to_freeze() that is normally used be selected.

Quoted 5 lines · On Tue, 22 Sep 2009 21:54:09 +0200 "Rafael J. Wysocki" <[email protected]> wrote:

Quoted 3 lines · Stephen Hemminger

By marking it cold, then the code path in kernel thread usage of try_to_freeze() that is normally used be selected.

In the code for try_to_freeze(), for optimization, it might help to tell the compiler to not favor the code path where the refigrator is being called.

Another way to do the same thing would be to do.

   if (unlikely(freezing(current))) {
	refrigerator();
	return 1;
   } else
	return 0;

or build unlikely into the freezing function (see need_resched).

I saw this by trying to minimize the number of intstructions in pktgen which is a special case.

Quoted 20 lines · Stephen Hemminger

Quoted 5 lines · On Tue, 22 Sep 2009 21:54:09 +0200 "Rafael J. Wysocki" <[email protected]> wrote:

Quoted 3 lines · Stephen Hemminger

By marking it cold, then the code path in kernel thread usage of try_to_freeze() that is normally used be selected.

In the code for try_to_freeze(), for optimization, it might help to tell the compiler to not favor the code path where the refigrator is being called.

Another way to do the same thing would be to do.

   if (unlikely(freezing(current))) {
	refrigerator();
	return 1;
   } else
	return 0;

Quoted 4 lines

or build unlikely into the freezing function (see need_resched).

I saw this by trying to minimize the number of intstructions in pktgen which is a special case.

OK, thanks.

Will it be fine with you if I add the patch to the suspend-2.6 tree with the above information in the changelog?

Rafael

Quoted 20 lines · Stephen Hemminger

Quoted 5 lines · On Tue, 22 Sep 2009 21:54:09 +0200 "Rafael J. Wysocki" <[email protected]> wrote:

Quoted 3 lines · Stephen Hemminger

By marking it cold, then the code path in kernel thread usage of try_to_freeze() that is normally used be selected.

In the code for try_to_freeze(), for optimization, it might help to tell the compiler to not favor the code path where the refigrator is being called.

Another way to do the same thing would be to do.

   if (unlikely(freezing(current))) {
	refrigerator();
	return 1;
   } else
	return 0;

Quoted 4 lines

or build unlikely into the freezing function (see need_resched).

I saw this by trying to minimize the number of intstructions in pktgen which is a special case.

OK, thanks.

Will it be fine with you if I add the patch to the suspend-2.6 tree with the above information in the changelog?

Rafael

Quoted 5 lines · On Tue, 22 Sep 2009 21:54:09 +0200 "Rafael J. Wysocki" <[email protected]> wrote:

Quoted 3 lines · Stephen Hemminger

By marking it cold, then the code path in kernel thread usage of try_to_freeze() that is normally used be selected.

In the code for try_to_freeze(), for optimization, it might help to tell the compiler to not favor the code path where the refigrator is being called.

Another way to do the same thing would be to do.

   if (unlikely(freezing(current))) {
	refrigerator();
	return 1;
   } else
	return 0;

or build unlikely into the freezing function (see need_resched).

I saw this by trying to minimize the number of intstructions in pktgen which is a special case.

By marking it cold, then the code path in kernel thread usage of try_to_freeze() that is normally used be selected.

Don't think it matters that much for performance but the concordance of this patch struck me as humorous.

Signed-off-by Stephen Hemminger <[email protected]>

include/linux/freezer.h +1 -1

@@ -47,7 +47,7 @@ static inline bool should_send_signal(st
 /* Takes and releases task alloc lock using task_lock() */
 extern int thaw_process(struct task_struct *p);
 
-extern void refrigerator(void);
+extern void refrigerator(void) __cold;
 extern int freeze_processes(void);
 extern void thaw_processes(void);