sched: reintroduce the sched_min_granularity tunable

we lost the sched_min_granularity tunable to a clever optimization
that uses the sched_latency/min_granularity ratio - but the ratio
is quite unintuitive to users and can also crash the kernel if the
ratio is set to 0. So reintroduce the min_granularity tunable,
while keeping the ratio maintained internally.

no functionality changed.

[ mingo@elte.hu: some fixlets. ]

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 1 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 155d7438f7..5457b6234e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1460,12 +1460,16 @@ extern void sched_idle_next(void);
 
 #ifdef CONFIG_SCHED_DEBUG
 extern unsigned int sysctl_sched_latency;
-extern unsigned int sysctl_sched_nr_latency;
+extern unsigned int sysctl_sched_min_granularity;
 extern unsigned int sysctl_sched_wakeup_granularity;
 extern unsigned int sysctl_sched_batch_wakeup_granularity;
 extern unsigned int sysctl_sched_child_runs_first;
 extern unsigned int sysctl_sched_features;
 extern unsigned int sysctl_sched_migration_cost;
+
+int sched_nr_latency_handler(struct ctl_table *table, int write,
+                struct file *file, void __user *buffer, size_t *length,
+                loff_t *ppos);
 #endif
 
 extern unsigned int sysctl_sched_compat_yield;