linux-kernel - [RFC][Patch 10/18] sched: update wake_affine path to use u64, s64 for weights

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Message-Id: <1303332697-16426-11-git-send-email-ncrao@google.com>
Date:	Wed, 20 Apr 2011 13:51:29 -0700
From:	Nikhil Rao <ncrao@...gle.com>
To:	Ingo Molnar <mingo@...e.hu>, Peter Zijlstra <peterz@...radead.org>
Cc:	Paul Turner <pjt@...gle.com>, Mike Galbraith <efault@....de>,
	linux-kernel@...r.kernel.org, Nikhil Rao <ncrao@...gle.com>
Subject: [RFC][Patch 10/18] sched: update wake_affine path to use u64, s64 for weights

Update the s64/u64 math in wake_affine() and effective_load() to handle
increased resolution.

Signed-off-by: Nikhil Rao <ncrao@...gle.com>
---
 kernel/sched_fair.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 029dd4f..2b030f4 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1388,7 +1388,7 @@ static void task_waking_fair(struct rq *rq, struct task_struct *p)
  * of group shares between cpus. Assuming the shares were perfectly aligned one
  * can calculate the shift in shares.
  */
-static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
+static s64 effective_load(struct task_group *tg, int cpu, s64 wl, s64 wg)
 {
 	struct sched_entity *se = tg->se[cpu];
 
@@ -1396,7 +1396,7 @@ static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
 		return wl;
 
 	for_each_sched_entity(se) {
-		long lw, w;
+		s64 lw, w;
 
 		tg = se->my_q->tg;
 		w = se->my_q->load.weight;
@@ -1409,7 +1409,7 @@ static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
 		wl += w;
 
 		if (lw > 0 && wl < lw)
-			wl = (wl * tg->shares) / lw;
+			wl = div64_s64(wl * tg->shares, lw);
 		else
 			wl = tg->shares;
 
@@ -1504,7 +1504,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
 
 	if (balanced ||
 	    (this_load <= load &&
-	     this_load + target_load(prev_cpu, idx) <= tl_per_task)) {
+	     this_load + target_load(prev_cpu, idx) <= (u64)tl_per_task)) {
 		/*
 		 * This domain has SD_WAKE_AFFINE and
 		 * p is cache cold in this domain, and
-- 
1.7.3.1

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