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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-09-29 18:45:00 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-12-04 21:26:50 +0100 |
| commit | 1de6e56ddc043437d335ee0455a1b34b73510c91 (patch) | |
| tree | dba0371b7d30a406027764a4e782faa0ff0d3d4b /kernel/rcu/tree.h | |
| parent | rcu: Short-circuit synchronize_sched_expedited() if only one CPU (diff) | |
| download | linux-1de6e56ddc043437d335ee0455a1b34b73510c91.tar.xz linux-1de6e56ddc043437d335ee0455a1b34b73510c91.zip | |
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 <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/tree.h')
| -rw-r--r-- | kernel/rcu/tree.h | 2 |
1 files changed, 2 insertions, 0 deletions
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. */ |