[PATCH tip/core/rcu 04/10] rcu: Switch last accelerate/advance to rcu_data structure

From: Paul E. McKenney
Date: Wed Aug 29 2018 - 19:08:28 EST


This commit removes ->last_accelerate and ->last_advance_all from the
rcu_dynticks structure and updates the code to access them from the
rcu_data structure.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.h | 4 ----
kernel/rcu/tree_plugin.h | 17 ++++++++---------
2 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 5d447ceba769..69bd6bec05bb 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -49,10 +49,6 @@ struct rcu_dynticks {
/* # times non-lazy CBs posted to CPU. */
unsigned long nonlazy_posted_snap;
/* idle-period nonlazy_posted snapshot. */
- unsigned long last_accelerate;
- /* Last jiffy CBs were accelerated. */
- unsigned long last_advance_all;
- /* Last jiffy CBs were all advanced. */
#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
};

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6511032371c1..45708164ddf9 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1597,16 +1597,14 @@ module_param(rcu_idle_lazy_gp_delay, int, 0644);
static bool __maybe_unused rcu_try_advance_all_cbs(void)
{
bool cbs_ready = false;
- struct rcu_data *rdp;
- struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+ struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
struct rcu_node *rnp;

/* Exit early if we advanced recently. */
- if (jiffies == rdtp->last_advance_all)
+ if (jiffies == rdp->last_advance_all)
return false;
- rdtp->last_advance_all = jiffies;
+ rdp->last_advance_all = jiffies;

- rdp = this_cpu_ptr(&rcu_data);
rnp = rdp->mynode;

/*
@@ -1635,6 +1633,7 @@ static bool __maybe_unused rcu_try_advance_all_cbs(void)
*/
int rcu_needs_cpu(u64 basemono, u64 *nextevt)
{
+ struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
unsigned long dj;

@@ -1655,7 +1654,7 @@ int rcu_needs_cpu(u64 basemono, u64 *nextevt)
invoke_rcu_core();
return 1;
}
- rdtp->last_accelerate = jiffies;
+ rdp->last_accelerate = jiffies;

/* Request timer delay depending on laziness, and round. */
if (!rdtp->all_lazy) {
@@ -1718,9 +1717,9 @@ static void rcu_prepare_for_idle(void)
* If we have not yet accelerated this jiffy, accelerate all
* callbacks on this CPU.
*/
- if (rdtp->last_accelerate == jiffies)
+ if (rdp->last_accelerate == jiffies)
return;
- rdtp->last_accelerate = jiffies;
+ rdp->last_accelerate = jiffies;
if (rcu_segcblist_pend_cbs(&rdp->cblist)) {
rnp = rdp->mynode;
raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
@@ -1769,7 +1768,7 @@ static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
unsigned long nlpd = rdtp->nonlazy_posted - rdtp->nonlazy_posted_snap;

sprintf(cp, "last_accelerate: %04lx/%04lx, nonlazy_posted: %ld, %c%c",
- rdtp->last_accelerate & 0xffff, jiffies & 0xffff,
+ rdp->last_accelerate & 0xffff, jiffies & 0xffff,
ulong2long(nlpd),
rdtp->all_lazy ? 'L' : '.',
rdp->tick_nohz_enabled_snap ? '.' : 'D');
--
2.17.1