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sched: Remove unnecessary RCU exclusion 

As Nick pointed out, and realized by myself when doing:
   sched: Fix balance vs hotplug race
the patch:
   sched: for_each_domain() vs RCU

is wrong, sched_domains are freed after synchronize_sched(), which
means disabling preemption is enough.

Reported-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-12-01 12:21:47 +01:00 committed by Ingo Molnar
parent 6cecd084d0
commit fb58bac5c7
1 changed files with 2 additions and 7 deletions
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9
kernel/sched_fair.c
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@ -1403,7 +1403,6 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag
new_cpu = prev_cpu; new_cpu = prev_cpu;
} }
rcu_read_lock();
for_each_domain(cpu, tmp) { for_each_domain(cpu, tmp) {
/* /*
* If power savings logic is enabled for a domain, see if we * If power savings logic is enabled for a domain, see if we
@ -1484,10 +1483,8 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag
update_shares(tmp); update_shares(tmp);
} }
if (affine_sd && wake_affine(affine_sd, p, sync)) { if (affine_sd && wake_affine(affine_sd, p, sync))
new_cpu = cpu; return cpu;
goto out;
}
while (sd) { while (sd) {
int load_idx = sd->forkexec_idx; int load_idx = sd->forkexec_idx;
@ -1528,8 +1525,6 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag
/* while loop will break here if sd == NULL */ /* while loop will break here if sd == NULL */
} }
out:
rcu_read_unlock();
return new_cpu; return new_cpu;
} }
#endif /* CONFIG_SMP */ #endif /* CONFIG_SMP */