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| author |   Zhouyi Zhou <zhouzhouyi@gmail.com> | 2019-03-20 03:33:00 +0000 |
|---|---|---|
| committer |   Paul E. McKenney <paulmck@linux.ibm.com> | 2019-03-26 14:38:38 -0700 |
| commit | 5d8a752e31aaa4c9703f201956a40b45ed791217 (patch) | |
| tree | c4e933bb91846e5d8f89e90fedd5b10b90cce9fd | |
| parent | rcu: Update jiffies_to_sched_qs and adjust_jiffies_till_sched_qs() comments (diff) | |
| download | linux-dev-5d8a752e31aaa4c9703f201956a40b45ed791217.tar.xz linux-dev-5d8a752e31aaa4c9703f201956a40b45ed791217.zip | |
rcu: Fix force_qs_rnp() header comment
Previously, threads blocked on offlining CPUS were migrated to the
root rcu_node structure, thus requiring RCU priority boosting on this
structure. However, since commit d19fb8d1f3f6 ("rcu: Don't migrate
blocked tasks even if all corresponding CPUs offline"), RCU does not
migrate blocked tasks. Consequently, RCU no longer does RCU priority
boosting on the root rcu_node structure as of commit 1be0085b515e ("rcu:
Don't initiate RCU priority boosting on root rcu_node").
This commit therefore brings comments for the force_qs_rnp() function's
header comment in line with this new no-root-boosting reality.
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
[ paulmck: Also remove obsolete comment on suppressing new grace periods. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| -rw-r--r-- | kernel/rcu/tree.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index e117732bcd5d..abc8512ceb5f 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2548,11 +2548,11 @@ void rcu_sched_clock_irq(int user) } /* - * Scan the leaf rcu_node structures, processing dyntick state for any that - * have not yet encountered a quiescent state, using the function specified. - * Also initiate boosting for any threads blocked on the root rcu_node. - * - * The caller must have suppressed start of new grace periods. + * Scan the leaf rcu_node structures. For each structure on which all + * CPUs have reported a quiescent state and on which there are tasks + * blocking the current grace period, initiate RCU priority boosting. + * Otherwise, invoke the specified function to check dyntick state for + * each CPU that has not yet reported a quiescent state. */ static void force_qs_rnp(int (*f)(struct rcu_data *rdp)) { |