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| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2007-08-23 15:18:02 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2007-08-23 15:18:02 +0200 |
| commit | f549da848eca595abca14ebc5e1bf00fd72aa53d (patch) | |
| tree | 25069c378b06c23f9f12a9e08c8f670d899f188b /kernel | |
| parent | f8700df7c419781efb34696de7e7f49717f8ede7 (diff) | |
| download | blackbird-op-linux-f549da848eca595abca14ebc5e1bf00fd72aa53d.tar.gz blackbird-op-linux-f549da848eca595abca14ebc5e1bf00fd72aa53d.zip | |
sched: skip updating rq's next_balance under null SD
Was playing with sched_smt_power_savings/sched_mc_power_savings and
found out that while the scheduler domains are reconstructed when sysfs
settings change, rebalance_domains() can get triggered with null domain
on other cpus, which is setting next_balance to jiffies + 60*HZ.
Resulting in no idle/busy balancing for 60 seconds.
Fix this.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index d96030db8ff7..a4b22d93e00d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3043,6 +3043,7 @@ static inline void rebalance_domains(int cpu, enum cpu_idle_type idle) struct sched_domain *sd; /* Earliest time when we have to do rebalance again */ unsigned long next_balance = jiffies + 60*HZ; + int update_next_balance = 0; for_each_domain(cpu, sd) { if (!(sd->flags & SD_LOAD_BALANCE)) @@ -3079,8 +3080,10 @@ static inline void rebalance_domains(int cpu, enum cpu_idle_type idle) if (sd->flags & SD_SERIALIZE) spin_unlock(&balancing); out: - if (time_after(next_balance, sd->last_balance + interval)) + if (time_after(next_balance, sd->last_balance + interval)) { next_balance = sd->last_balance + interval; + update_next_balance = 1; + } /* * Stop the load balance at this level. There is another @@ -3090,7 +3093,14 @@ out: if (!balance) break; } - rq->next_balance = next_balance; + + /* + * next_balance will be updated only when there is a need. + * When the cpu is attached to null domain for ex, it will not be + * updated. + */ + if (likely(update_next_balance)) + rq->next_balance = next_balance; } /* |
