linux-kernel - [PATCH v2 08/19] sched/numa: Remove unused task_capacity from numa

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Date:   Wed, 20 Jun 2018 22:32:49 +0530
From:   Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Rik van Riel <riel@...riel.com>,
        Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH v2 08/19] sched/numa: Remove unused task_capacity from numa_stats

task_capacity field in struct numa_stats is redundant.
Also move nr_running for better packing within the struct.

No functional changes.

Running SPECjbb2005 on a 4 node machine and comparing bops/JVM
JVMS  LAST_PATCH  WITH_PATCH  %CHANGE
16    25308.6     25377.3     0.271
1     72964       72287       -0.92

Acked-by: Mel Gorman <mgorman@...hsingularity.net>
Acked-by: Rik van Riel <riel@...riel.com>
Signed-off-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
---
 kernel/sched/fair.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ed60fbd..0580a27 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1411,14 +1411,12 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
 
 /* Cached statistics for all CPUs within a node */
 struct numa_stats {
-	unsigned long nr_running;
 	unsigned long load;
 
 	/* Total compute capacity of CPUs on a node */
 	unsigned long compute_capacity;
 
-	/* Approximate capacity in terms of runnable tasks on a node */
-	unsigned long task_capacity;
+	unsigned int nr_running;
 	int has_free_capacity;
 };
 
@@ -1456,9 +1454,9 @@ static void update_numa_stats(struct numa_stats *ns, int nid)
 	smt = DIV_ROUND_UP(SCHED_CAPACITY_SCALE * cpus, ns->compute_capacity);
 	capacity = cpus / smt; /* cores */
 
-	ns->task_capacity = min_t(unsigned, capacity,
+	capacity = min_t(unsigned, capacity,
 		DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE));
-	ns->has_free_capacity = (ns->nr_running < ns->task_capacity);
+	ns->has_free_capacity = (ns->nr_running < capacity);
 }
 
 struct task_numa_env {
-- 
1.8.3.1