diff mbox series

[v3,14/25] context_tracking, rcu: Rename rcu_dynticks_curr_cpu_in_eqs() into rcu_watching_curr_cpu()

Message ID 20240724144325.3307148-15-vschneid@redhat.com (mailing list archive)
State Accepted
Commit 45e70dcbfc5ce2dbc8435dbb296d8385d0116866
Headers show
Series context_tracking, rcu: Spring cleaning of dynticks references | expand

Commit Message

Valentin Schneider July 24, 2024, 2:43 p.m. UTC 
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, reflect that change in the related helpers.

Note that "watching" is the opposite of "in EQS", so the negation is lifted
out of the helper and into the callsites.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
---
 include/linux/context_tracking.h | 12 ++++++++----
 kernel/context_tracking.c        |  6 +++---
 kernel/rcu/tree.c                |  6 +++---
 3 files changed, 14 insertions(+), 10 deletions(-)

Comments

Frederic Weisbecker July 25, 2024, 12:10 p.m. UTC | #1 
Le Wed, Jul 24, 2024 at 04:43:14PM +0200, Valentin Schneider a écrit :
> The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
> RCU_WATCHING, reflect that change in the related helpers.
> 
> Note that "watching" is the opposite of "in EQS", so the negation is lifted
> out of the helper and into the callsites.
> 
> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

You may need to update the patch title on this one.

Thanks.
Valentin Schneider July 25, 2024, 2:46 p.m. UTC | #2 
On 25/07/24 14:10, Frederic Weisbecker wrote:
> Le Wed, Jul 24, 2024 at 04:43:14PM +0200, Valentin Schneider a écrit :
>> The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
>> RCU_WATCHING, reflect that change in the related helpers.
>>
>> Note that "watching" is the opposite of "in EQS", so the negation is lifted
>> out of the helper and into the callsites.
>>
>> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
>> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
>
> You may need to update the patch title on this one.
>

Duh, there's a few of these, sorry about & thanks for spotting them.

> Thanks.
diff mbox series

Patch

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index a6c36780cc3bd..d53092ffa9dba 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -113,13 +113,17 @@  extern void ct_idle_enter(void);
 extern void ct_idle_exit(void);
 
 /*
- * Is the current CPU in an extended quiescent state?
+ * Is RCU watching the current CPU (IOW, it is not in an extended quiescent state)?
+ *
+ * Note that this returns the actual boolean data (watching / not watching),
+ * whereas ct_rcu_watching() returns the RCU_WATCHING subvariable of
+ * context_tracking.state.
  *
  * No ordering, as we are sampling CPU-local information.
  */
-static __always_inline bool rcu_dynticks_curr_cpu_in_eqs(void)
+static __always_inline bool rcu_is_watching_curr_cpu(void)
 {
-	return !(raw_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_RCU_WATCHING);
+	return raw_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_RCU_WATCHING;
 }
 
 /*
@@ -140,7 +144,7 @@  static __always_inline bool warn_rcu_enter(void)
 	 * lots of the actual reporting also relies on RCU.
 	 */
 	preempt_disable_notrace();
-	if (rcu_dynticks_curr_cpu_in_eqs()) {
+	if (!rcu_is_watching_curr_cpu()) {
 		ret = true;
 		ct_state_inc(CT_RCU_WATCHING);
 	}
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 1c16a7336360f..e64bb746cd9b3 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -212,7 +212,7 @@  void noinstr ct_nmi_exit(void)
 	 * to us!)
 	 */
 	WARN_ON_ONCE(ct_nmi_nesting() <= 0);
-	WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs());
+	WARN_ON_ONCE(!rcu_is_watching_curr_cpu());
 
 	/*
 	 * If the nesting level is not 1, the CPU wasn't RCU-idle, so
@@ -271,7 +271,7 @@  void noinstr ct_nmi_enter(void)
 	 * to be in the outermost NMI handler that interrupted an RCU-idle
 	 * period (observation due to Andy Lutomirski).
 	 */
-	if (rcu_dynticks_curr_cpu_in_eqs()) {
+	if (!rcu_is_watching_curr_cpu()) {
 
 		if (!in_nmi())
 			rcu_task_enter();
@@ -281,7 +281,7 @@  void noinstr ct_nmi_enter(void)
 		// ... but is watching here.
 
 		instrumentation_begin();
-		// instrumentation for the noinstr rcu_dynticks_curr_cpu_in_eqs()
+		// instrumentation for the noinstr rcu_is_watching_curr_cpu()
 		instrument_atomic_read(&ct->state, sizeof(ct->state));
 		// instrumentation for the noinstr ct_kernel_enter_state()
 		instrument_atomic_write(&ct->state, sizeof(ct->state));
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8a88d278e198e..90a0c14f80542 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -593,7 +593,7 @@  void rcu_irq_exit_check_preempt(void)
 	RCU_LOCKDEP_WARN(ct_nmi_nesting() !=
 			 CT_NESTING_IRQ_NONIDLE,
 			 "Bad RCU  nmi_nesting counter\n");
-	RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(),
+	RCU_LOCKDEP_WARN(!rcu_is_watching_curr_cpu(),
 			 "RCU in extended quiescent state!");
 }
 #endif /* #ifdef CONFIG_PROVE_RCU */
@@ -633,7 +633,7 @@  void __rcu_irq_enter_check_tick(void)
 	if (in_nmi())
 		return;
 
-	RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(),
+	RCU_LOCKDEP_WARN(!rcu_is_watching_curr_cpu(),
 			 "Illegal rcu_irq_enter_check_tick() from extended quiescent state");
 
 	if (!tick_nohz_full_cpu(rdp->cpu) ||
@@ -715,7 +715,7 @@  notrace bool rcu_is_watching(void)
 	bool ret;
 
 	preempt_disable_notrace();
-	ret = !rcu_dynticks_curr_cpu_in_eqs();
+	ret = rcu_is_watching_curr_cpu();
 	preempt_enable_notrace();
 	return ret;
 }