UPSTREAM: sched/headers: Move loadavg related definitions from <linux/sched.h> to <linux/sched/loadavg.h>

Move these bits to <linux/sched/loadavg.h>, to reduce the size and
complexity of <linux/sched.h>.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

(cherry picked from commit dea38c74cb9205341f52b8d8ae18f61247a43ea8)

Bug: 111308141
Test: modified lmkd to use PSI and tested using lmkd_unit_test

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: If827d04c87fa957f684a7a879766d9c910b1da90
diff --git a/include/linux/sched/loadavg.h b/include/linux/sched/loadavg.h
index 3ae74be..c392e28 100644
--- a/include/linux/sched/loadavg.h
+++ b/include/linux/sched/loadavg.h
@@ -3,4 +3,31 @@
 
 #include <linux/sched.h>
 
+/*
+ * These are the constant used to fake the fixed-point load-average
+ * counting. Some notes:
+ *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
+ *    a load-average precision of 10 bits integer + 11 bits fractional
+ *  - if you want to count load-averages more often, you need more
+ *    precision, or rounding will get you. With 2-second counting freq,
+ *    the EXP_n values would be 1981, 2034 and 2043 if still using only
+ *    11 bit fractions.
+ */
+extern unsigned long avenrun[];		/* Load averages */
+extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
+
+#define FSHIFT		11		/* nr of bits of precision */
+#define FIXED_1		(1<<FSHIFT)	/* 1.0 as fixed-point */
+#define LOAD_FREQ	(5*HZ+1)	/* 5 sec intervals */
+#define EXP_1		1884		/* 1/exp(5sec/1min) as fixed-point */
+#define EXP_5		2014		/* 1/exp(5sec/5min) */
+#define EXP_15		2037		/* 1/exp(5sec/15min) */
+
+#define CALC_LOAD(load,exp,n) \
+	load *= exp; \
+	load += n*(FIXED_1-exp); \
+	load >>= FSHIFT;
+
+extern void calc_global_load(unsigned long ticks);
+
 #endif /* _LINUX_SCHED_LOADAVG_H */