sched: allow architectures to specify sched_clock_stable

Allow CONFIG_HAVE_UNSTABLE_SCHED_CLOCK architectures to still specify
that their sched_clock() implementation is reliable.

This will be used by x86 to switch on a faster sched_clock_cpu()
implementation on certain CPU types.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar
2009-02-26 20:20:29 +01:00
parent 694593e337
commit b342501cd3
2 changed files with 30 additions and 25 deletions

View File

@@ -1670,6 +1670,16 @@ static inline int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask)
return set_cpus_allowed_ptr(p, &new_mask);
}
/*
* Architectures can set this to 1 if they have specified
* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK in their arch Kconfig,
* but then during bootup it turns out that sched_clock()
* is reliable after all:
*/
#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
extern int sched_clock_stable;
#endif
extern unsigned long long sched_clock(void);
extern void sched_clock_init(void);