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rcu: Implement rcu_segcblist_is_offloaded() config dependent 

This commit simplifies the use of the rcu_segcblist_is_offloaded() API so
that its callers no longer need to check the RCU_NOCB_CPU Kconfig option.
Note that rcu_segcblist_is_offloaded() is defined in the header file,
which means that the generated code should be just as efficient as before.

Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Frederic Weisbecker 2020-09-21 14:43:40 +02:00 committed by Paul E. McKenney
parent 1eafe075bf
commit e3771c850d
2 changed files with 8 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/rcu/rcu_segcblist.h
View File

@ -62,7 +62,7 @@ static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
/* Is the specified rcu_segcblist offloaded? */ /* Is the specified rcu_segcblist offloaded? */
static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp) static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
{ {
return rsclp->offloaded; return IS_ENABLED(CONFIG_RCU_NOCB_CPU) && rsclp->offloaded;
} }
/* /*

21
kernel/rcu/tree.c
View File

@ -1603,8 +1603,7 @@ static bool __note_gp_changes(struct rcu_node *rnp, struct rcu_data *rdp)
{ {
bool ret = false; bool ret = false;
bool need_qs; bool need_qs;
const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);
rcu_segcblist_is_offloaded(&rdp->cblist);
raw_lockdep_assert_held_rcu_node(rnp); raw_lockdep_assert_held_rcu_node(rnp);
@ -2048,8 +2047,7 @@ static void rcu_gp_cleanup(void)
needgp = true; needgp = true;
} }
/* Advance CBs to reduce false positives below. */ /* Advance CBs to reduce false positives below. */
offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);
rcu_segcblist_is_offloaded(&rdp->cblist);
if ((offloaded || !rcu_accelerate_cbs(rnp, rdp)) && needgp) { if ((offloaded || !rcu_accelerate_cbs(rnp, rdp)) && needgp) {
WRITE_ONCE(rcu_state.gp_flags, RCU_GP_FLAG_INIT); WRITE_ONCE(rcu_state.gp_flags, RCU_GP_FLAG_INIT);
WRITE_ONCE(rcu_state.gp_req_activity, jiffies); WRITE_ONCE(rcu_state.gp_req_activity, jiffies);
@ -2248,8 +2246,7 @@ rcu_report_qs_rdp(struct rcu_data *rdp)
unsigned long flags; unsigned long flags;
unsigned long mask; unsigned long mask;
bool needwake = false; bool needwake = false;
const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);
rcu_segcblist_is_offloaded(&rdp->cblist);
struct rcu_node *rnp; struct rcu_node *rnp;
WARN_ON_ONCE(rdp->cpu != smp_processor_id()); WARN_ON_ONCE(rdp->cpu != smp_processor_id());
@ -2417,8 +2414,7 @@ static void rcu_do_batch(struct rcu_data *rdp)
{ {
int div; int div;
unsigned long flags; unsigned long flags;
const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);
rcu_segcblist_is_offloaded(&rdp->cblist);
struct rcu_head *rhp; struct rcu_head *rhp;
struct rcu_cblist rcl = RCU_CBLIST_INITIALIZER(rcl); struct rcu_cblist rcl = RCU_CBLIST_INITIALIZER(rcl);
long bl, count; long bl, count;
@ -2675,8 +2671,7 @@ static __latent_entropy void rcu_core(void)
unsigned long flags; unsigned long flags;
struct rcu_data *rdp = raw_cpu_ptr(&rcu_data); struct rcu_data *rdp = raw_cpu_ptr(&rcu_data);
struct rcu_node *rnp = rdp->mynode; struct rcu_node *rnp = rdp->mynode;
const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);
rcu_segcblist_is_offloaded(&rdp->cblist);
if (cpu_is_offline(smp_processor_id())) if (cpu_is_offline(smp_processor_id()))
return; return;
@ -2978,8 +2973,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func)
rcu_segcblist_n_cbs(&rdp->cblist)); rcu_segcblist_n_cbs(&rdp->cblist));
/* Go handle any RCU core processing required. */ /* Go handle any RCU core processing required. */
if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) && if (unlikely(rcu_segcblist_is_offloaded(&rdp->cblist))) {
unlikely(rcu_segcblist_is_offloaded(&rdp->cblist))) {
__call_rcu_nocb_wake(rdp, was_alldone, flags); /* unlocks */ __call_rcu_nocb_wake(rdp, was_alldone, flags); /* unlocks */
} else { } else {
__call_rcu_core(rdp, head, flags); __call_rcu_core(rdp, head, flags);
@ -3712,8 +3706,7 @@ static int rcu_pending(int user)
/* Has RCU gone idle with this CPU needing another grace period? */ /* Has RCU gone idle with this CPU needing another grace period? */
if (!gp_in_progress && rcu_segcblist_is_enabled(&rdp->cblist) && if (!gp_in_progress && rcu_segcblist_is_enabled(&rdp->cblist) &&
(!IS_ENABLED(CONFIG_RCU_NOCB_CPU) || !rcu_segcblist_is_offloaded(&rdp->cblist) &&
!rcu_segcblist_is_offloaded(&rdp->cblist)) &&
!rcu_segcblist_restempty(&rdp->cblist, RCU_NEXT_READY_TAIL)) !rcu_segcblist_restempty(&rdp->cblist, RCU_NEXT_READY_TAIL))
return 1; return 1;