Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit aa6da514 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Remove "cpu" argument to rcu_needs_cpu() 



The "cpu" argument to rcu_needs_cpu() is always the current CPU, so drop
it.  This in turn allows the "cpu" argument to rcu_cpu_has_callbacks()
to be removed, which allows the uses of "cpu" in both functions to be
replaced with a this_cpu_ptr().  Again, the anticipated cross-CPU uses
of these functions has been replaced by NO_HZ_FULL.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarPranith Kumar <bobby.prani@gmail.com>
parent 38200cf2

include/linux/rcupdate.h

+1 −1
Original line number Diff line number Diff line
@@ -1103,7 +1103,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) 
	__kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))



#if defined(CONFIG_TINY_RCU) || defined(CONFIG_RCU_NOCB_CPU_ALL)

static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)

static inline int rcu_needs_cpu(unsigned long *delta_jiffies)

{

	*delta_jiffies = ULONG_MAX;

	return 0;

include/linux/rcutree.h

+1 −1
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ 


void rcu_note_context_switch(void);

#ifndef CONFIG_RCU_NOCB_CPU_ALL

int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies);

int rcu_needs_cpu(unsigned long *delta_jiffies);

#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */

void rcu_cpu_stall_reset(void);

kernel/rcu/tree.c

+2 −2
Original line number Diff line number Diff line
@@ -3159,7 +3159,7 @@ static int rcu_pending(void) 
 * non-NULL, store an indication of whether all callbacks are lazy.

 * (If there are no callbacks, all of them are deemed to be lazy.)

 */

static int __maybe_unused rcu_cpu_has_callbacks(int cpu, bool *all_lazy)

static int __maybe_unused rcu_cpu_has_callbacks(bool *all_lazy)

{

	bool al = true;

	bool hc = false;
@@ -3167,7 +3167,7 @@ static int __maybe_unused rcu_cpu_has_callbacks(int cpu, bool *all_lazy) 
	struct rcu_state *rsp;



	for_each_rcu_flavor(rsp) {

		rdp = per_cpu_ptr(rsp->rda, cpu);

		rdp = this_cpu_ptr(rsp->rda);

		if (!rdp->nxtlist)

			continue;

		hc = true;

kernel/rcu/tree_plugin.h

+6 −6
Original line number Diff line number Diff line
@@ -1512,10 +1512,10 @@ static void rcu_prepare_kthreads(int cpu) 
 * any flavor of RCU.

 */

#ifndef CONFIG_RCU_NOCB_CPU_ALL

int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)

int rcu_needs_cpu(unsigned long *delta_jiffies)

{

	*delta_jiffies = ULONG_MAX;

	return rcu_cpu_has_callbacks(cpu, NULL);

	return rcu_cpu_has_callbacks(NULL);

}

#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
@@ -1624,15 +1624,15 @@ static bool __maybe_unused rcu_try_advance_all_cbs(void) 
 * The caller must have disabled interrupts.

 */

#ifndef CONFIG_RCU_NOCB_CPU_ALL

int rcu_needs_cpu(int cpu, unsigned long *dj)

int rcu_needs_cpu(unsigned long *dj)

{

	struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);

	struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);



	/* Snapshot to detect later posting of non-lazy callback. */

	rdtp->nonlazy_posted_snap = rdtp->nonlazy_posted;



	/* If no callbacks, RCU doesn't need the CPU. */

	if (!rcu_cpu_has_callbacks(cpu, &rdtp->all_lazy)) {

	if (!rcu_cpu_has_callbacks(&rdtp->all_lazy)) {

		*dj = ULONG_MAX;

		return 0;

	}
@@ -1679,7 +1679,7 @@ static void rcu_prepare_for_idle(int cpu) 
	/* Handle nohz enablement switches conservatively. */

	tne = ACCESS_ONCE(tick_nohz_active);

	if (tne != rdtp->tick_nohz_enabled_snap) {

		if (rcu_cpu_has_callbacks(cpu, NULL))

		if (rcu_cpu_has_callbacks(NULL))

			invoke_rcu_core(); /* force nohz to see update. */

		rdtp->tick_nohz_enabled_snap = tne;

		return;

kernel/time/tick-sched.c

+1 −1
Original line number Diff line number Diff line
@@ -585,7 +585,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, 
		last_jiffies = jiffies;

	} while (read_seqretry(&jiffies_lock, seq));



	if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) ||

	if (rcu_needs_cpu(&rcu_delta_jiffies) ||

	    arch_needs_cpu() || irq_work_needs_cpu()) {

		next_jiffies = last_jiffies + 1;

		delta_jiffies = 1;