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rcu: Switch lazy counts to rcu_data structure
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This commit removes ->all_lazy, ->nonlazy_posted and ->nonlazy_posted_snap
from the rcu_dynticks structure and updates the code to access them from
the rcu_data structure.

Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Lucas Lee Jing Yi <[email protected]>
Signed-off-by: Carlos Ayrton Lopez Arroyo <[email protected]>
Signed-off-by: clarencelol <[email protected]>
Signed-off-by: Anush02198 <[email protected]>
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paulmck authored and Anush02198 committed Jun 30, 2021
1 parent d5a20f3 commit ca1b520
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Showing 2 changed files with 10 additions and 20 deletions.
7 changes: 0 additions & 7 deletions kernel/rcu/tree.h
Original file line number Diff line number Diff line change
Expand Up @@ -43,13 +43,6 @@ struct rcu_dynticks {
atomic_t dynticks; /* Even value for idle, else odd. */
bool rcu_need_heavy_qs; /* GP old, need heavy quiescent state. */
bool rcu_urgent_qs; /* GP old need light quiescent state. */
#ifdef CONFIG_RCU_FAST_NO_HZ
bool all_lazy; /* Are all CPU's CBs lazy? */
unsigned long nonlazy_posted;
/* # times non-lazy CBs posted to CPU. */
unsigned long nonlazy_posted_snap;
/* idle-period nonlazy_posted snapshot. */
#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
};

/* Communicate arguments to a workqueue handler. */
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23 changes: 10 additions & 13 deletions kernel/rcu/tree_plugin.h
Original file line number Diff line number Diff line change
Expand Up @@ -1635,16 +1635,15 @@ 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;

lockdep_assert_irqs_disabled();

/* Snapshot to detect later posting of non-lazy callback. */
rdtp->nonlazy_posted_snap = rdtp->nonlazy_posted;
rdp->nonlazy_posted_snap = rdp->nonlazy_posted;

/* If no callbacks, RCU doesn't need the CPU. */
if (!rcu_cpu_has_callbacks(&rdtp->all_lazy)) {
if (!rcu_cpu_has_callbacks(&rdp->all_lazy)) {
*nextevt = KTIME_MAX;
return 0;
}
Expand All @@ -1658,7 +1657,7 @@ int rcu_needs_cpu(u64 basemono, u64 *nextevt)
rdp->last_accelerate = jiffies;

/* Request timer delay depending on laziness, and round. */
if (!rdtp->all_lazy) {
if (!rdp->all_lazy) {
dj = round_up(rcu_idle_gp_delay + jiffies,
rcu_idle_gp_delay) - jiffies;
} else {
Expand All @@ -1682,7 +1681,6 @@ static void rcu_prepare_for_idle(void)
{
bool needwake;
struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
struct rcu_node *rnp;
int tne;

Expand All @@ -1706,10 +1704,10 @@ static void rcu_prepare_for_idle(void)
* callbacks, invoke RCU core for the side-effect of recalculating
* idle duration on re-entry to idle.
*/
if (rdtp->all_lazy &&
rdtp->nonlazy_posted != rdtp->nonlazy_posted_snap) {
rdtp->all_lazy = false;
rdtp->nonlazy_posted_snap = rdtp->nonlazy_posted;
if (rdp->all_lazy &&
rdp->nonlazy_posted != rdp->nonlazy_posted_snap) {
rdp->all_lazy = false;
rdp->nonlazy_posted_snap = rdp->nonlazy_posted;
invoke_rcu_core();
return;
}
Expand Down Expand Up @@ -1755,7 +1753,7 @@ static void rcu_cleanup_after_idle(void)
*/
static void rcu_idle_count_callbacks_posted(void)
{
__this_cpu_add(rcu_dynticks.nonlazy_posted, 1);
__this_cpu_add(rcu_data.nonlazy_posted, 1);
}

#endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */
Expand All @@ -1765,13 +1763,12 @@ static void rcu_idle_count_callbacks_posted(void)
static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
{
struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
unsigned long nlpd = rdtp->nonlazy_posted - rdtp->nonlazy_posted_snap;
unsigned long nlpd = rdp->nonlazy_posted - rdp->nonlazy_posted_snap;

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

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