Commit 4dca1af4 authored by Ankur Arora's avatar Ankur Arora Committed by Boqun Feng
Browse files

rcu: rename PREEMPT_AUTO to PREEMPT_LAZY 



Replace mentions of PREEMPT_AUTO with PREEMPT_LAZY.

Also, since PREMPT_LAZY implies PREEMPTION, we can reduce the
TASKS_RCU selection criteria from this:

  NEED_TASKS_RCU && (PREEMPTION || PREEMPT_AUTO)

to this:

  NEED_TASKS_RCU && PREEMPTION

CC: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Reviewed-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarAnkur Arora <ankur.a.arora@oracle.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarBoqun Feng <boqun.feng@gmail.com>
parent ad6b5b73

include/linux/srcutiny.h

+1 −1
Original line number Diff line number Diff line
@@ -64,7 +64,7 @@ static inline int __srcu_read_lock(struct srcu_struct *ssp) 
{

	int idx;



	preempt_disable();  // Needed for PREEMPT_AUTO

	preempt_disable();  // Needed for PREEMPT_LAZY

	idx = ((READ_ONCE(ssp->srcu_idx) + 1) & 0x2) >> 1;

	WRITE_ONCE(ssp->srcu_lock_nesting[idx], READ_ONCE(ssp->srcu_lock_nesting[idx]) + 1);

	preempt_enable();

kernel/rcu/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -91,7 +91,7 @@ config NEED_TASKS_RCU 


config TASKS_RCU

	bool

	default NEED_TASKS_RCU && (PREEMPTION || PREEMPT_AUTO)

	default NEED_TASKS_RCU && PREEMPTION

	select IRQ_WORK



config FORCE_TASKS_RUDE_RCU

kernel/rcu/srcutiny.c

+7 −7
Original line number Diff line number Diff line
@@ -98,7 +98,7 @@ void __srcu_read_unlock(struct srcu_struct *ssp, int idx) 
{

	int newval;



	preempt_disable();  // Needed for PREEMPT_AUTO

	preempt_disable();  // Needed for PREEMPT_LAZY

	newval = READ_ONCE(ssp->srcu_lock_nesting[idx]) - 1;

	WRITE_ONCE(ssp->srcu_lock_nesting[idx], newval);

	preempt_enable();
@@ -120,7 +120,7 @@ void srcu_drive_gp(struct work_struct *wp) 
	struct srcu_struct *ssp;



	ssp = container_of(wp, struct srcu_struct, srcu_work);

	preempt_disable();  // Needed for PREEMPT_AUTO

	preempt_disable();  // Needed for PREEMPT_LAZY

	if (ssp->srcu_gp_running || ULONG_CMP_GE(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max))) {

		preempt_enable();

		return; /* Already running or nothing to do. */
@@ -138,7 +138,7 @@ void srcu_drive_gp(struct work_struct *wp) 
	WRITE_ONCE(ssp->srcu_gp_waiting, true);  /* srcu_read_unlock() wakes! */

	preempt_enable();

	swait_event_exclusive(ssp->srcu_wq, !READ_ONCE(ssp->srcu_lock_nesting[idx]));

	preempt_disable();  // Needed for PREEMPT_AUTO

	preempt_disable();  // Needed for PREEMPT_LAZY

	WRITE_ONCE(ssp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */

	WRITE_ONCE(ssp->srcu_idx, ssp->srcu_idx + 1);

	preempt_enable();
@@ -159,7 +159,7 @@ void srcu_drive_gp(struct work_struct *wp) 
	 * at interrupt level, but the ->srcu_gp_running checks will

	 * straighten that out.

	 */

	preempt_disable();  // Needed for PREEMPT_AUTO

	preempt_disable();  // Needed for PREEMPT_LAZY

	WRITE_ONCE(ssp->srcu_gp_running, false);

	idx = ULONG_CMP_LT(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max));

	preempt_enable();
@@ -172,7 +172,7 @@ static void srcu_gp_start_if_needed(struct srcu_struct *ssp) 
{

	unsigned long cookie;



	preempt_disable();  // Needed for PREEMPT_AUTO

	preempt_disable();  // Needed for PREEMPT_LAZY

	cookie = get_state_synchronize_srcu(ssp);

	if (ULONG_CMP_GE(READ_ONCE(ssp->srcu_idx_max), cookie)) {

		preempt_enable();
@@ -199,7 +199,7 @@ void call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp, 


	rhp->func = func;

	rhp->next = NULL;

	preempt_disable();  // Needed for PREEMPT_AUTO

	preempt_disable();  // Needed for PREEMPT_LAZY

	local_irq_save(flags);

	*ssp->srcu_cb_tail = rhp;

	ssp->srcu_cb_tail = &rhp->next;
@@ -261,7 +261,7 @@ unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp) 
{

	unsigned long ret;



	preempt_disable();  // Needed for PREEMPT_AUTO

	preempt_disable();  // Needed for PREEMPT_LAZY

	ret = get_state_synchronize_srcu(ssp);

	srcu_gp_start_if_needed(ssp);

	preempt_enable();