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>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 8981e52..a063d19 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1670,6 +1670,16 @@
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);