Commit d38c8fe4 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

Merge branches 'doc.2022.06.21a', 'fixes.2022.07.19a', 'nocb.2022.07.19a',... 

Merge branches 'doc.2022.06.21a', 'fixes.2022.07.19a', 'nocb.2022.07.19a', 'poll.2022.07.21a', 'rcu-tasks.2022.06.21a' and 'torture.2022.06.21a' into HEAD

doc.2022.06.21a: Documentation updates.
fixes.2022.07.19a: Miscellaneous fixes.
nocb.2022.07.19a: Callback-offload updates.
poll.2022.07.21a: Polled grace-period updates.
rcu-tasks.2022.06.21a: Tasks RCU updates.
torture.2022.06.21a: Torture-test updates.
parents 89f7f291 a03ae49c 0578e14c 28787e04 e72ee5e1 7bf336fb

Documentation/admin-guide/kernel-parameters.txt

+24 −0
Original line number Diff line number Diff line
@@ -3659,6 +3659,9 @@ 
			just as if they had also been called out in the

			rcu_nocbs= boot parameter.



			Note that this argument takes precedence over

			the CONFIG_RCU_NOCB_CPU_DEFAULT_ALL option.



	noiotrap	[SH] Disables trapped I/O port accesses.



	noirqdebug	[X86-32] Disables the code which attempts to detect and
@@ -4557,6 +4560,9 @@ 
			no-callback mode from boot but the mode may be

			toggled at runtime via cpusets.



			Note that this argument takes precedence over

			the CONFIG_RCU_NOCB_CPU_DEFAULT_ALL option.



	rcu_nocb_poll	[KNL]

			Rather than requiring that offloaded CPUs

			(specified by rcu_nocbs= above) explicitly
@@ -5799,6 +5805,24 @@ 
			expediting.  Set to zero to disable automatic

			expediting.



	srcutree.srcu_max_nodelay [KNL]

			Specifies the number of no-delay instances

			per jiffy for which the SRCU grace period

			worker thread will be rescheduled with zero

			delay. Beyond this limit, worker thread will

			be rescheduled with a sleep delay of one jiffy.



	srcutree.srcu_max_nodelay_phase [KNL]

			Specifies the per-grace-period phase, number of

			non-sleeping polls of readers. Beyond this limit,

			grace period worker thread will be rescheduled

			with a sleep delay of one jiffy, between each

			rescan of the readers, for a grace period phase.



	srcutree.srcu_retry_check_delay [KNL]

			Specifies number of microseconds of non-sleeping

			delay between each non-sleeping poll of readers.



	srcutree.small_contention_lim [KNL]

			Specifies the number of update-side contention

			events per jiffy will be tolerated before

include/linux/rcupdate.h

+20 −8
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ void call_rcu(struct rcu_head *head, rcu_callback_t func); 
void rcu_barrier_tasks(void);

void rcu_barrier_tasks_rude(void);

void synchronize_rcu(void);

unsigned long get_completed_synchronize_rcu(void);



#ifdef CONFIG_PREEMPT_RCU
@@ -169,12 +170,23 @@ void synchronize_rcu_tasks(void); 
# endif



# ifdef CONFIG_TASKS_TRACE_RCU

// Bits for ->trc_reader_special.b.need_qs field.

#define TRC_NEED_QS		0x1  // Task needs a quiescent state.

#define TRC_NEED_QS_CHECKED	0x2  // Task has been checked for needing quiescent state.



u8 rcu_trc_cmpxchg_need_qs(struct task_struct *t, u8 old, u8 new);

void rcu_tasks_trace_qs_blkd(struct task_struct *t);



# define rcu_tasks_trace_qs(t)							\

	do {									\

		if (!likely(READ_ONCE((t)->trc_reader_checked)) &&	\

		    !unlikely(READ_ONCE((t)->trc_reader_nesting))) {	\

			smp_store_release(&(t)->trc_reader_checked, true); \

			smp_mb(); /* Readers partitioned by store. */	\

		int ___rttq_nesting = READ_ONCE((t)->trc_reader_nesting);	\

										\

		if (likely(!READ_ONCE((t)->trc_reader_special.b.need_qs)) &&	\

		    likely(!___rttq_nesting)) {					\

			rcu_trc_cmpxchg_need_qs((t), 0,	TRC_NEED_QS_CHECKED);	\

		} else if (___rttq_nesting && ___rttq_nesting != INT_MIN &&	\

			   !READ_ONCE((t)->trc_reader_special.b.blocked)) {	\

			rcu_tasks_trace_qs_blkd(t);				\

		}								\

	} while (0)

# else
@@ -184,7 +196,7 @@ void synchronize_rcu_tasks(void); 
#define rcu_tasks_qs(t, preempt)					\

do {									\

	rcu_tasks_classic_qs((t), (preempt));				\

	rcu_tasks_trace_qs((t));					\

	rcu_tasks_trace_qs(t);						\

} while (0)



# ifdef CONFIG_TASKS_RUDE_RCU

include/linux/rcupdate_trace.h

+1 −1
Original line number Diff line number Diff line
@@ -75,7 +75,7 @@ static inline void rcu_read_unlock_trace(void) 
	nesting = READ_ONCE(t->trc_reader_nesting) - 1;

	barrier(); // Critical section before disabling.

	// Disable IPI-based setting of .need_qs.

	WRITE_ONCE(t->trc_reader_nesting, INT_MIN);

	WRITE_ONCE(t->trc_reader_nesting, INT_MIN + nesting);

	if (likely(!READ_ONCE(t->trc_reader_special.s)) || nesting) {

		WRITE_ONCE(t->trc_reader_nesting, nesting);

		return;  // We assume shallow reader nesting.

include/linux/rcutiny.h

+20 −1
Original line number Diff line number Diff line
@@ -23,6 +23,16 @@ static inline void cond_synchronize_rcu(unsigned long oldstate) 
	might_sleep();

}



static inline unsigned long start_poll_synchronize_rcu_expedited(void)

{

	return start_poll_synchronize_rcu();

}



static inline void cond_synchronize_rcu_expedited(unsigned long oldstate)

{

	cond_synchronize_rcu(oldstate);

}



extern void rcu_barrier(void);



static inline void synchronize_rcu_expedited(void)
@@ -38,7 +48,7 @@ static inline void synchronize_rcu_expedited(void) 
 */

extern void kvfree(const void *addr);



static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)

static inline void __kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)

{

	if (head) {

		call_rcu(head, func);
@@ -51,6 +61,15 @@ static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func) 
	kvfree((void *) func);

}



#ifdef CONFIG_KASAN_GENERIC

void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func);

#else

static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)

{

	__kvfree_call_rcu(head, func);

}

#endif



void rcu_qs(void);



static inline void rcu_softirq_qs(void)

include/linux/rcutree.h

+2 −0
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ bool rcu_eqs_special_set(int cpu); 
void rcu_momentary_dyntick_idle(void);

void kfree_rcu_scheduler_running(void);

bool rcu_gp_might_be_stalled(void);

unsigned long start_poll_synchronize_rcu_expedited(void);

void cond_synchronize_rcu_expedited(unsigned long oldstate);

unsigned long get_state_synchronize_rcu(void);

unsigned long start_poll_synchronize_rcu(void);

bool poll_state_synchronize_rcu(unsigned long oldstate);