sched: Make tunable scaling style configurable

As scaling now takes place on all kind of cpu add/remove events a user
that configures values via proc should be able to configure if his set
values are still rescaled or kept whatever happens.

As the comments state that log2 was just a second guess that worked the
interface is not just designed for on/off, but to choose a scaling type.
Currently this allows none, log and linear, but more important it allwos
us to keep the interface even if someone has an even better idea how to
scale the values.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1259579808-11357-3-git-send-email-ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 14 insertions, 0 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index e5cc53514caa..d10406e5fdfe 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -251,6 +251,8 @@ static int min_sched_granularity_ns = 100000;		/* 100 usecs */
 static int max_sched_granularity_ns = NSEC_PER_SEC;     /* 1 second */
 static int min_wakeup_granularity_ns;                   /* 0 usecs */
 static int max_wakeup_granularity_ns = NSEC_PER_SEC;    /* 1 second */
+static int min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
+static int max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1;
 #endif
 
 static struct ctl_table kern_table[] = {
@@ -306,6 +308,18 @@ static struct ctl_table kern_table[] = {
         },
         {
                 .ctl_name       = CTL_UNNUMBERED,
+                .procname       = "sched_tunable_scaling",
+                .data           = &sysctl_sched_tunable_scaling,
+                .maxlen         = sizeof(enum sched_tunable_scaling),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec_minmax,
+                .strategy       = &sysctl_intvec,
+                .extra1         = &min_sched_tunable_scaling,
+                .extra2         = &max_sched_tunable_scaling,
+        },
+
+        {
+                .ctl_name       = CTL_UNNUMBERED,
                 .procname       = "sched_shares_thresh",
                 .data           = &sysctl_sched_shares_thresh,
                 .maxlen         = sizeof(unsigned int),