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Groups > linux.kernel > #1542451
| From | Boqun Feng <boqun.feng@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() |
| Date | 2016-12-15 03:50 +0100 |
| Message-ID | <sOuhj-8sr-9@gated-at.bofh.it> (permalink) |
| References | <sOuhj-8sr-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
->qsmask of an RCU leaf node is usually more sparse than the
corresponding cpu_possible_mask. So replace the
for_each_leaf_node_possible_cpu() in force_qs_rnp() with
for_each_leaf_node_cpu() to save several checks.
[Note we need to use "1UL << bit" instead of "1 << bit" to generate the
corresponding mask for a bit because @mask is unsigned long, this was
spotted by Colin Ian King <colin.king@canonical.com> and CoverityScan in
a previous version of this patch.]
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
kernel/rcu/tree.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 4e5b81c843de..1ef13e63bc95 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3046,13 +3046,11 @@ static void force_qs_rnp(struct rcu_state *rsp,
continue;
}
}
- for_each_leaf_node_possible_cpu(rnp, cpu) {
- unsigned long bit = leaf_node_cpu_bit(rnp, cpu);
- if ((rnp->qsmask & bit) != 0) {
- if (f(per_cpu_ptr(rsp->rda, cpu), isidle, maxj))
- mask |= bit;
- }
- }
+
+ for_each_leaf_node_cpu(rnp, rnp->qsmask, cpu)
+ if (f(per_cpu_ptr(rsp->rda, cpu), isidle, maxj))
+ mask |= leaf_node_cpu_bit(rnp, cpu);
+
if (mask != 0) {
/* Idle/offline CPUs, report (releases rnp->lock. */
rcu_report_qs_rnp(mask, rsp, rnp, rnp->gpnum, flags);
--
2.10.2
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[RFC v2 0/5] rcu: Introduce for_each_leaf_node_cpu() Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 03:50 +0100
[RFC v2 1/5] rcu: Introduce for_each_leaf_node_cpu() Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 03:50 +0100
Re: [RFC v2 1/5] rcu: Introduce for_each_leaf_node_cpu() Mark Rutland <mark.rutland@arm.com> - 2016-12-15 12:50 +0100
Re: [RFC v2 1/5] rcu: Introduce for_each_leaf_node_cpu() Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 15:40 +0100
Re: [RFC v2 1/5] rcu: Introduce for_each_leaf_node_cpu() Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 16:20 +0100
Re: [RFC v2 1/5] rcu: Introduce for_each_leaf_node_cpu() Mark Rutland <mark.rutland@arm.com> - 2016-12-15 16:20 +0100
[RFC v2.1 1/5] rcu: Introduce for_each_leaf_node_cpu() Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 16:30 +0100
Re: [RFC v2.1 1/5] rcu: Introduce for_each_leaf_node_cpu() Mark Rutland <mark.rutland@arm.com> - 2016-12-15 16:40 +0100
[RFC v2 2/5] rcu: Use for_each_leaf_node_cpu() in RCU stall checking Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 03:50 +0100
[RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 03:50 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Mark Rutland <mark.rutland@arm.com> - 2016-12-15 13:10 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 15:50 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Colin Ian King <colin.king@canonical.com> - 2016-12-15 16:00 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Boqun Feng <boqun.feng@gmail.com> - 2016-12-19 16:20 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-12-20 06:10 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Boqun Feng <boqun.feng@gmail.com> - 2016-12-20 07:00 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Boqun Feng <boqun.feng@gmail.com> - 2016-12-20 09:20 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-12-20 16:40 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-12-20 16:30 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Boqun Feng <boqun.feng@gmail.com> - 2016-12-21 03:40 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-12-21 04:50 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Boqun Feng <boqun.feng@gmail.com> - 2016-12-21 05:20 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-12-21 17:50 +0100
Re: [RFC v2 4/5] rcu: Use for_each_leaf_node_cpu() in force_qs_rnp() Boqun Feng <boqun.feng@gmail.com> - 2016-12-22 02:10 +0100
[RFC v2 5/5] rcu: Use for_each_leaf_node_cpu() in online CPU iteration Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 03:50 +0100
[RFC v2 3/5] rcu: Use for_each_leaf_node_cpu() in ->expmask iteration Boqun Feng <boqun.feng@gmail.com> - 2016-12-15 03:50 +0100
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