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From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org,
	Morten Rasmussen <morten.rasmussen@arm.com>
Subject: [PATCH 2/7] sched/fair: Fix comment in calculate_imbalance()
Date: Fri, 29 Apr 2016 20:32:39 +0100	[thread overview]
Message-ID: <1461958364-675-3-git-send-email-dietmar.eggemann@arm.com> (raw)
In-Reply-To: <1461958364-675-1-git-send-email-dietmar.eggemann@arm.com>

The comment survived from commit 2dd73a4f09be ("[PATCH] sched:
implement smpnice") in which the selection of busiest and
busiest->avg_load (max_load) was based on if(avg_load > max_load
&& sum_nr_running > group->cpu_power / SCHED_LOAD_SCALE).

Commit b18855500fc4 ("sched/balancing: Fix 'local->avg_load >
sds->avg_load' case in calculate_imbalance()") added the second
operand of the or operator.

Update this comment accordingly and also use the current variable
names.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
---
 kernel/sched/fair.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c77e01b55ec2..bc19fee94f39 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6998,9 +6998,10 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
 	}
 
 	/*
-	 * In the presence of smp nice balancing, certain scenarios can have
-	 * max load less than avg load(as we skip the groups at or below
-	 * its cpu_capacity, while calculating max_load..)
+	 * Avg load of busiest sg can be less and avg load of local sg can
+	 * be greater than avg load across all sgs of sd because avg load
+	 * factors in sg capacity and sgs with smaller group_type are
+	 * skipped when updating the busiest sg.
 	 */
 	if (busiest->avg_load <= sds->avg_load ||
 	    local->avg_load >= sds->avg_load) {
-- 
1.9.1

  parent reply	other threads:[~2016-04-29 19:33 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-29 19:32 [PATCH 0/7] sched/fair: fixes and cleanups Dietmar Eggemann
2016-04-29 19:32 ` [PATCH 1/7] sched/fair: Remove remaining power aware scheduling comments Dietmar Eggemann
2016-05-05  9:42   ` [tip:sched/core] sched/fair: Remove stale " tip-bot for Dietmar Eggemann
2016-04-29 19:32 ` Dietmar Eggemann [this message]
2016-05-05  9:42   ` [tip:sched/core] sched/fair: Fix comment in calculate_imbalance() tip-bot for Dietmar Eggemann
2016-04-29 19:32 ` [PATCH 3/7] sched/fair: Correct unit of load_above_capacity Dietmar Eggemann
2016-05-03 10:52   ` Peter Zijlstra
2016-05-03 14:56     ` Morten Rasmussen
2016-05-12 10:31   ` [tip:sched/core] " tip-bot for Morten Rasmussen
2016-05-12 21:48     ` Yuyang Du
2016-05-13  8:22       ` Vincent Guittot
2016-05-19 15:36         ` Morten Rasmussen
2016-05-20  8:17           ` Vincent Guittot
2016-05-23 20:24           ` Yuyang Du
2016-05-30 22:35             ` Yuyang Du
2016-04-29 19:32 ` [PATCH 4/7] sched/fair: Clean up the logic in fix_small_imbalance() Dietmar Eggemann
2016-05-03 10:12   ` Peter Zijlstra
2016-05-03 16:53     ` Dietmar Eggemann
2016-04-29 19:32 ` [PATCH 5/7] sched/fair: Remove cpu_avg_load_per_task() Dietmar Eggemann
2016-04-29 19:32 ` [PATCH 6/7] sched/fair: Reorder code in update_sd_lb_stats() Dietmar Eggemann
2016-04-29 19:32 ` [PATCH 7/7] sched/fair: Use group_cfs_rq(se) instead of se->my_q Dietmar Eggemann

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