From ac367c1c621b75689f6d5cd8301d364ba2c9f292 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sat, 11 Mar 2017 07:14:06 -0800 Subject: srcu: Add grace-period sequence numbers This commit adds grace-period sequence numbers, which will be used to handle mid-boot grace periods and per-CPU callback lists. Signed-off-by: Paul E. McKenney --- kernel/rcu/srcu.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) (limited to 'kernel/rcu/srcu.c') diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c index 70286f6..d464986d 100644 --- a/kernel/rcu/srcu.c +++ b/kernel/rcu/srcu.c @@ -110,6 +110,7 @@ static inline void rcu_batch_move(struct rcu_batch *to, struct rcu_batch *from) static int init_srcu_struct_fields(struct srcu_struct *sp) { sp->completed = 0; + sp->srcu_gp_seq = 0; spin_lock_init(&sp->queue_lock); sp->srcu_state = SRCU_STATE_IDLE; rcu_batch_init(&sp->batch_queue); @@ -319,6 +320,15 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock); #define SYNCHRONIZE_SRCU_EXP_TRYCOUNT 12 /* + * Start an SRCU grace period. + */ +static void srcu_gp_start(struct srcu_struct *sp) +{ + WRITE_ONCE(sp->srcu_state, SRCU_STATE_SCAN1); + rcu_seq_start(&sp->srcu_gp_seq); +} + +/* * @@@ Wait until all pre-existing readers complete. Such readers * will have used the index specified by "idx". * the caller should ensures the ->completed is not changed while checking @@ -355,6 +365,15 @@ static void srcu_flip(struct srcu_struct *sp) } /* + * End an SRCU grace period. + */ +static void srcu_gp_end(struct srcu_struct *sp) +{ + rcu_seq_end(&sp->srcu_gp_seq); + WRITE_ONCE(sp->srcu_state, SRCU_STATE_DONE); +} + +/* * Enqueue an SRCU callback on the specified srcu_struct structure, * initiating grace-period processing if it is not already running. * @@ -392,7 +411,7 @@ void call_srcu(struct srcu_struct *sp, struct rcu_head *head, smp_mb__after_unlock_lock(); /* Caller's prior accesses before GP. */ rcu_batch_queue(&sp->batch_queue, head); if (READ_ONCE(sp->srcu_state) == SRCU_STATE_IDLE) { - WRITE_ONCE(sp->srcu_state, SRCU_STATE_SCAN1); + srcu_gp_start(sp); queue_delayed_work(system_power_efficient_wq, &sp->work, 0); } spin_unlock_irqrestore(&sp->queue_lock, flags); @@ -426,7 +445,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) smp_mb__after_unlock_lock(); /* Caller's prior accesses before GP. */ if (READ_ONCE(sp->srcu_state) == SRCU_STATE_IDLE) { /* steal the processing owner */ - WRITE_ONCE(sp->srcu_state, SRCU_STATE_SCAN1); + srcu_gp_start(sp); rcu_batch_queue(&sp->batch_check0, head); spin_unlock_irq(&sp->queue_lock); /* give the processing owner to work_struct */ @@ -561,7 +580,7 @@ static void srcu_advance_batches(struct srcu_struct *sp, int trycount) */ if (sp->srcu_state == SRCU_STATE_DONE) - WRITE_ONCE(sp->srcu_state, SRCU_STATE_SCAN1); + srcu_gp_start(sp); if (sp->srcu_state == SRCU_STATE_SCAN1) { idx = 1 ^ (sp->completed & 1); @@ -608,7 +627,7 @@ static void srcu_advance_batches(struct srcu_struct *sp, int trycount) */ rcu_batch_move(&sp->batch_done, &sp->batch_check1); - WRITE_ONCE(sp->srcu_state, SRCU_STATE_DONE); + srcu_gp_end(sp); } } -- cgit v1.1