sched/fair: Kill the unused 'sched_shares_window_ns' tunable

The last user of this tunable was removed in 2012 in commit:

  82958366 ("sched: Replace update_shares weight distribution with per-entity computation")

Delete it since its very existence confuses people.
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161019141059.26408-1-matt@codeblueprint.co.ukSigned-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/sched/sysctl.h

@@ -36,7 +36,6 @@ extern unsigned int sysctl_numa_balancing_scan_size;
 extern unsigned int sysctl_sched_migration_cost;
 extern unsigned int sysctl_sched_nr_migrate;
 extern unsigned int sysctl_sched_time_avg;
-extern unsigned int sysctl_sched_shares_window;
 
 int sched_proc_update_handler(struct ctl_table *table, int write,
 		void __user *buffer, size_t *length,

kernel/sched/fair.c

@@ -93,13 +93,6 @@ unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL;
 
 const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
 
-/*
- * The exponential sliding  window over which load is averaged for shares
- * distribution.
- * (default: 10msec)
- */
-unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL;
-
 #ifdef CONFIG_CFS_BANDWIDTH
 /*
  * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool

kernel/sysctl.c

@@ -347,13 +347,6 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{
-		.procname	= "sched_shares_window_ns",
-		.data		= &sysctl_sched_shares_window,
-		.maxlen		= sizeof(unsigned int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
 #ifdef CONFIG_SCHEDSTATS
 	{
 		.procname	= "sched_schedstats",