Commit fda70207 authored by Valentin Schneider's avatar Valentin Schneider Committed by Neeraj Upadhyay
Browse files

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



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: default avatarValentin Schneider <vschneid@redhat.com>
Reviewed-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Signed-off-by: default avatarNeeraj Upadhyay <neeraj.upadhyay@kernel.org>
parent b1b91fd1

include/linux/context_tracking.h

+8 −4
Original line number Diff line number Diff line
@@ -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);

	}

kernel/context_tracking.c

+3 −3
Original line number Diff line number Diff line
@@ -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));

kernel/rcu/tree.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

}