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, 7 insertions, 4 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 3b4efbe26445..6e3b63c06856 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -235,11 +235,14 @@ static struct ctl_table kern_table[] = {
 #ifdef CONFIG_SCHED_DEBUG
         {
                 .ctl_name       = CTL_UNNUMBERED,
-                .procname       = "sched_nr_latency",
-                .data           = &sysctl_sched_nr_latency,
+                .procname       = "sched_min_granularity_ns",
+                .data           = &sysctl_sched_min_granularity,
                 .maxlen         = sizeof(unsigned int),
                 .mode           = 0644,
-                .proc_handler   = &proc_dointvec,
+                .proc_handler   = &sched_nr_latency_handler,
+                .strategy       = &sysctl_intvec,
+                .extra1         = &min_sched_granularity_ns,
+                .extra2         = &max_sched_granularity_ns,
         },
         {
                 .ctl_name       = CTL_UNNUMBERED,
@@ -247,7 +250,7 @@ static struct ctl_table kern_table[] = {
                 .data           = &sysctl_sched_latency,
                 .maxlen         = sizeof(unsigned int),
                 .mode           = 0644,
-                .proc_handler   = &proc_dointvec_minmax,
+                .proc_handler   = &sched_nr_latency_handler,
                 .strategy       = &sysctl_intvec,
                 .extra1         = &min_sched_granularity_ns,
                 .extra2         = &max_sched_granularity_ns,