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authorChristian Ehrhardt <ehrhardt@linux.vnet.ibm.com>2009-11-30 12:16:46 +0100
committerIngo Molnar <mingo@elte.hu>2009-12-09 10:03:58 +0100
commit0bcdcf28c979869f44e05121b96ff2cfb05bd8e6 (patch)
treec70b8fb37fec9badf95ac2ea679407334f580ae5 /kernel/sched.c
parent57785df5ac53c70da9fb53696130f3c551bfe1f9 (diff)
downloadlinux-0bcdcf28c979869f44e05121b96ff2cfb05bd8e6.tar.gz
sched: Fix missing sched tunable recalculation on cpu add/remove
Based on Peter Zijlstras patch suggestion this enables recalculation of the scheduler tunables in response of a change in the number of cpus. It also adds a max of eight cpus that are considered in that scaling. Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1259579808-11357-2-git-send-email-ehrhardt@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c29
1 files changed, 16 insertions, 13 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 3878f5018007..b54ecf84b6be 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -814,6 +814,7 @@ const_debug unsigned int sysctl_sched_nr_migrate = 32;
* default: 0.25ms
*/
unsigned int sysctl_sched_shares_ratelimit = 250000;
+unsigned int normalized_sysctl_sched_shares_ratelimit = 250000;
/*
* Inject some fuzzyness into changing the per-cpu group shares
@@ -1814,6 +1815,7 @@ static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
#endif
static void calc_load_account_active(struct rq *this_rq);
+static void update_sysctl(void);
static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
{
@@ -7028,22 +7030,23 @@ cpumask_var_t nohz_cpu_mask;
*
* This idea comes from the SD scheduler of Con Kolivas:
*/
-static inline void sched_init_granularity(void)
+static void update_sysctl(void)
{
- unsigned int factor = 1 + ilog2(num_online_cpus());
- const unsigned long limit = 200000000;
-
- sysctl_sched_min_granularity *= factor;
- if (sysctl_sched_min_granularity > limit)
- sysctl_sched_min_granularity = limit;
-
- sysctl_sched_latency *= factor;
- if (sysctl_sched_latency > limit)
- sysctl_sched_latency = limit;
+ unsigned int cpus = min(num_online_cpus(), 8U);
+ unsigned int factor = 1 + ilog2(cpus);
- sysctl_sched_wakeup_granularity *= factor;
+#define SET_SYSCTL(name) \
+ (sysctl_##name = (factor) * normalized_sysctl_##name)
+ SET_SYSCTL(sched_min_granularity);
+ SET_SYSCTL(sched_latency);
+ SET_SYSCTL(sched_wakeup_granularity);
+ SET_SYSCTL(sched_shares_ratelimit);
+#undef SET_SYSCTL
+}
- sysctl_sched_shares_ratelimit *= factor;
+static inline void sched_init_granularity(void)
+{
+ update_sysctl();
}
#ifdef CONFIG_SMP