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context_tracking, rcu: Rename rcu_dynticks_curr_cpu_in_eqs() into rcu_is_watching_curr_cpu()

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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>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
This commit is contained in:
Valentin Schneider 2024-04-16 11:01:23 +02:00 committed by Neeraj Upadhyay
parent b1b91fd1be
commit fda7020713
3 changed files with 14 additions and 10 deletions
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12
include/linux/context_tracking.h
View File

@ -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);
}

6
kernel/context_tracking.c
View File

@ -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));

6
kernel/rcu/tree.c
View File

@ -601,7 +601,7 @@ 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 */
@ -641,7 +641,7 @@ 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) ||
@ -723,7 +723,7 @@ 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;
}