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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-07-16 18:37:06 +0400 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-07-16 21:44:46 +0400 |
| commit | 187497fa5e9e9383820d33e48b87f8200a747c2a (patch) | |
| tree | 7941e912b1a123cf2213797ca49a70bdfa550778 | |
| parent | 1823172ab582eb54456fd1354869bb850a1196ba (diff) | |
| download | linux-187497fa5e9e9383820d33e48b87f8200a747c2a.tar.xz | |
rcu: Allow for NULL tick_nohz_full_mask when nohz_full= missing
If there isn't a nohz_full= kernel parameter specified, then
tick_nohz_full_mask can legitimately be NULL. This can cause
problems when RCU's boot code tries to cpumask_or() this value into
rcu_nocb_mask. In addition, if NO_HZ_FULL_ALL=y, there is no point
in doing the cpumask_or() in the first place because this will cause
RCU_NOCB_CPU_ALL=y, which in turn will have all bits already set in
rcu_nocb_mask.
This commit therefore avoids the cpumask_or() if NO_HZ_FULL_ALL=y
and checks for !tick_nohz_full_running otherwise, this latter check
catching cases when there was no nohz_full= kernel parameter specified.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index f62b7f2f6abd..00dc411e9676 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2479,9 +2479,10 @@ static void __init rcu_spawn_nocb_kthreads(struct rcu_state *rsp) if (rcu_nocb_mask == NULL) return; -#ifdef CONFIG_NO_HZ_FULL - cpumask_or(rcu_nocb_mask, rcu_nocb_mask, tick_nohz_full_mask); -#endif /* #ifdef CONFIG_NO_HZ_FULL */ +#if defined(CONFIG_NO_HZ_FULL) && !defined(CONFIG_NO_HZ_FULL_ALL) + if (tick_nohz_full_running) + cpumask_or(rcu_nocb_mask, rcu_nocb_mask, tick_nohz_full_mask); +#endif /* #if defined(CONFIG_NO_HZ_FULL) && !defined(CONFIG_NO_HZ_FULL_ALL) */ if (ls == -1) { ls = int_sqrt(nr_cpu_ids); rcu_nocb_leader_stride = ls; |