2008-08-19 23:22:49

by Matt Helsley

Subject: [PATCH 2/6] Container Freezer: uninline thaw_process()

Now that the cgroup freezer system also calls thaw_process() inlining these
functions uses more space. Uninlining returns some space:

Before:
text data bss dec hex filename
4260872 275532 290816 4827220 49a854 vmlinux
After:
text data bss dec hex filename
4260852 275532 290816 4827200 49a840 vmlinux

Signed-off-by: Matt Helsley <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
---
include/linux/freezer.h | 29 +++--------------------------
kernel/freezer.c | 31 +++++++++++++++++++++++++++++++
2 files changed, 34 insertions(+), 26 deletions(-)

Index: linux-2.6.27-rc1-mm1/include/linux/freezer.h
===================================================================
--- linux-2.6.27-rc1-mm1.orig/include/linux/freezer.h
+++ linux-2.6.27-rc1-mm1/include/linux/freezer.h
@@ -46,34 +46,11 @@ static inline bool should_send_signal(st

/*
* Wake up a frozen process
- *
- * task_lock() is needed to prevent the race with refrigerator() which may
- * occur if the freezing of tasks fails. Namely, without the lock, if the
- * freezing of tasks failed, thaw_tasks() might have run before a task in
- * refrigerator() could call frozen_process(), in which case the task would be
- * frozen and no one would thaw it.
*/
-static inline int __thaw_process(struct task_struct *p)
-{
- if (frozen(p)) {
- p->flags &= ~PF_FROZEN;
- return 1;
- }
- clear_freeze_flag(p);
- return 0;
-}
+extern int __thaw_process(struct task_struct *p);

-static inline int thaw_process(struct task_struct *p)
-{
- task_lock(p);
- if (__thaw_process(p) == 1) {
- task_unlock(p);
- wake_up_process(p);
- return 1;
- }
- task_unlock(p);
- return 0;
-}
+/* Takes and releases task alloc lock using task_lock() */
+extern int thaw_process(struct task_struct *p);

extern void refrigerator(void);
extern int freeze_processes(void);
Index: linux-2.6.27-rc1-mm1/kernel/freezer.c
===================================================================
--- linux-2.6.27-rc1-mm1.orig/kernel/freezer.c
+++ linux-2.6.27-rc1-mm1/kernel/freezer.c
@@ -120,3 +120,34 @@ void cancel_freezing(struct task_struct
spin_unlock_irqrestore(&p->sighand->siglock, flags);
}
}
+
+/*
+ * Wake up a frozen process
+ *
+ * task_lock() is needed to prevent the race with refrigerator() which may
+ * occur if the freezing of tasks fails. Namely, without the lock, if the
+ * freezing of tasks failed, thaw_tasks() might have run before a task in
+ * refrigerator() could call frozen_process(), in which case the task would be
+ * frozen and no one would thaw it.
+ */
+int __thaw_process(struct task_struct *p)
+{
+ if (frozen(p)) {
+ p->flags &= ~PF_FROZEN;
+ return 1;
+ }
+ clear_freeze_flag(p);
+ return 0;
+}
+
+int thaw_process(struct task_struct *p)
+{
+ task_lock(p);
+ if (__thaw_process(p) == 1) {
+ task_unlock(p);
+ wake_up_process(p);
+ return 1;
+ }
+ task_unlock(p);
+ return 0;
+}

--

2008-08-20 16:57:17

by Pavel Machek

Subject: Re: [PATCH 2/6] Container Freezer: uninline thaw_process()

On Tue 2008-08-19 16:22:34, Matt Helsley wrote:
> Now that the cgroup freezer system also calls thaw_process() inlining these
> functions uses more space. Uninlining returns some space:
>
> Before:
> text data bss dec hex filename
> 4260872 275532 290816 4827220 49a854 vmlinux
> After:
> text data bss dec hex filename
> 4260852 275532 290816 4827200 49a840 vmlinux


20 bytes...

Does it still compile out if freezer is disabled?

Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html