From: Paul E. McKenney Date: Tue, 29 Sep 2015 16:45:00 +0000 (-0700) Subject: rcu: Clarify role of ->expmaskinitnext X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=1de6e56ddc043437d335ee0455a1b34b73510c91;p=linux-beck.git rcu: Clarify role of ->expmaskinitnext Analogy with the ->qsmaskinitnext field might lead one to believe that ->expmaskinitnext tracks online CPUs. This belief is incorrect: Any CPU that has ever been online will have its bit set in the ->expmaskinitnext field. This commit therefore adds a comment to make this clear, at least to people who read comments. Signed-off-by: Paul E. McKenney --- diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index f32bebb6bc90..8151971a8978 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -178,6 +178,8 @@ struct rcu_node { /* beginning of each expedited GP. */ unsigned long expmaskinitnext; /* Online CPUs for next expedited GP. */ + /* Any CPU that has ever been online will */ + /* have its bit set. */ unsigned long grpmask; /* Mask to apply to parent qsmask. */ /* Only one bit will be set in this mask. */ int grplo; /* lowest-numbered CPU or group here. */