[v4 RFC PATCH 3/4] timers: /proc/sys sysctl hook to enable timermigration

From: Arun R Bharadwaj
Date: Wed Apr 01 2009 - 07:36:31 EST


* Arun R Bharadwaj <arun@xxxxxxxxxxxxxxxxxx> [2009-04-01 17:01:28]:

This patch creates the /proc/sys sysctl interface at
/proc/sys/kernel/timer_migration

Timer migration is enabled by default.

To disable timer migration, when CONFIG_SCHED_DEBUG = y,

echo 0 > /proc/sys/kernel/timer_migration

Signed-off-by: Arun R Bharadwaj <arun@xxxxxxxxxxxxxxxxxx>
---
include/linux/sched.h | 1 +
kernel/sched.c | 1 +
kernel/sysctl.c | 8 ++++++++
3 files changed, 10 insertions(+)

Index: linux.trees.git/include/linux/sched.h
===================================================================
--- linux.trees.git.orig/include/linux/sched.h
+++ linux.trees.git/include/linux/sched.h
@@ -1763,6 +1763,7 @@ extern unsigned int sysctl_sched_child_r
extern unsigned int sysctl_sched_features;
extern unsigned int sysctl_sched_migration_cost;
extern unsigned int sysctl_sched_nr_migrate;
+extern unsigned int sysctl_timer_migration;

int sched_nr_latency_handler(struct ctl_table *table, int write,
struct file *file, void __user *buffer, size_t *length,
Index: linux.trees.git/kernel/sysctl.c
===================================================================
--- linux.trees.git.orig/kernel/sysctl.c
+++ linux.trees.git/kernel/sysctl.c
@@ -328,6 +328,14 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "timer_migration",
+ .data = &sysctl_timer_migration,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
#endif
{
.ctl_name = CTL_UNNUMBERED,
Index: linux.trees.git/kernel/sched.c
===================================================================
--- linux.trees.git.orig/kernel/sched.c
+++ linux.trees.git/kernel/sched.c
@@ -7445,6 +7445,7 @@ static void sched_domain_node_span(int n
#endif /* CONFIG_NUMA */

int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
+const_debug unsigned int sysctl_timer_migration = 1;

/*
* The cpus mask in sched_group and sched_domain hangs off the end.
--
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