sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD

There are several definitions of those functions/macros in places that
mess with fixed-point load averages.  Provide an official version.

[akpm@linux-foundation.org: fix missed conversion in block/blk-iolatency.c]
Link: http://lkml.kernel.org/r/20180828172258.3185-5-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Suren Baghdasaryan <surenb@google.com>
Tested-by: Daniel Drake <drake@endlessm.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <jweiner@fb.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Enderborg <peter.enderborg@sony.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 35c48d7..28f80d2 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -153,7 +153,7 @@
 #define BLKIOLATENCY_MAX_WIN_SIZE NSEC_PER_SEC
 /*
  * These are the constants used to fake the fixed-point moving average
- * calculation just like load average.  The call to CALC_LOAD folds
+ * calculation just like load average.  The call to calc_load() folds
  * (FIXED_1 (2048) - exp_factor) * new_sample into lat_avg.  The sampling
  * window size is bucketed to try to approximately calculate average
  * latency such that 1/exp (decay rate) is [1 min, 2.5 min) when windows
@@ -248,7 +248,7 @@
 		return;
 
 	/*
-	 * CALC_LOAD takes in a number stored in fixed point representation.
+	 * calc_load() takes in a number stored in fixed point representation.
 	 * Because we are using this for IO time in ns, the values stored
 	 * are significantly larger than the FIXED_1 denominator (2048).
 	 * Therefore, rounding errors in the calculation are negligible and
@@ -257,7 +257,9 @@
 	exp_idx = min_t(int, BLKIOLATENCY_NR_EXP_FACTORS - 1,
 			div64_u64(iolat->cur_win_nsec,
 				  BLKIOLATENCY_EXP_BUCKET_SIZE));
-	CALC_LOAD(iolat->lat_avg, iolatency_exp_factors[exp_idx], stat->rqs.mean);
+	iolat->lat_avg = calc_load(iolat->lat_avg,
+				   iolatency_exp_factors[exp_idx],
+				   stat->rqs.mean);
 }
 
 static inline bool iolatency_may_queue(struct iolatency_grp *iolat,