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Subject[PATCH rcu 04/14] rcu: Eliminate rcu_implicit_dynticks_qs() local variable ruqp
Date
The rcu_implicit_dynticks_qs() function's local variable ruqp references
the ->rcu_urgent_qs field in the rcu_data structure referenced by the
function parameter rdp, with a rather odd method for computing the
pointer to this field. This commit therefore simplifies things and
saves a couple of lines of code by replacing each instance of ruqp with
&rdp->need_heavy_qs.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tree.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 18d2f35d1450..0bfebec94277 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1219,7 +1219,6 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp)
static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
{
unsigned long jtsq;
- bool *ruqp;
struct rcu_node *rnp = rdp->mynode;

/*
@@ -1284,16 +1283,15 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
* is set way high.
*/
jtsq = READ_ONCE(jiffies_to_sched_qs);
- ruqp = per_cpu_ptr(&rcu_data.rcu_urgent_qs, rdp->cpu);
if (!READ_ONCE(rdp->rcu_need_heavy_qs) &&
(time_after(jiffies, rcu_state.gp_start + jtsq * 2) ||
time_after(jiffies, rcu_state.jiffies_resched) ||
rcu_state.cbovld)) {
WRITE_ONCE(rdp->rcu_need_heavy_qs, true);
/* Store rcu_need_heavy_qs before rcu_urgent_qs. */
- smp_store_release(ruqp, true);
+ smp_store_release(&rdp->rcu_urgent_qs, true);
} else if (time_after(jiffies, rcu_state.gp_start + jtsq)) {
- WRITE_ONCE(*ruqp, true);
+ WRITE_ONCE(rdp->rcu_urgent_qs, true);
}

/*
@@ -1307,7 +1305,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
if (tick_nohz_full_cpu(rdp->cpu) &&
(time_after(jiffies, READ_ONCE(rdp->last_fqs_resched) + jtsq * 3) ||
rcu_state.cbovld)) {
- WRITE_ONCE(*ruqp, true);
+ WRITE_ONCE(rdp->rcu_urgent_qs, true);
resched_cpu(rdp->cpu);
WRITE_ONCE(rdp->last_fqs_resched, jiffies);
}
--
2.31.1.189.g2e36527f23
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