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| author | Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> | 2009-11-30 12:16:46 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-12-09 10:03:58 +0100 |
| commit | 0bcdcf28c979869f44e05121b96ff2cfb05bd8e6 (patch) | |
| tree | c70b8fb37fec9badf95ac2ea679407334f580ae5 /kernel/sched.c | |
| parent | 57785df5ac53c70da9fb53696130f3c551bfe1f9 (diff) | |
| download | linux-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.c | 29 |
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 |