From 25cc6d18cb2fc9964adf2c1edb53c5539e279382 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Sat, 30 Jan 2010 13:28:35 -0500 Subject: [PATCH] URCU: rename light/heavy barriers to slave/master Signed-off-by: Mathieu Desnoyers --- urcu-static.h | 31 +++++++++++++++++++++++-------- urcu.c | 20 ++++++++++---------- 2 files changed, 33 insertions(+), 18 deletions(-) diff --git a/urcu-static.h b/urcu-static.h index 5a75dde..f2c452a 100644 --- a/urcu-static.h +++ b/urcu-static.h @@ -160,10 +160,25 @@ static inline void debug_yield_init(void) } #endif +/* + * RCU memory barrier broadcast group. Currently, only broadcast to all process + * threads is supported (group 0). + * + * Slave barriers are only guaranteed to be ordered wrt master barriers. + * + * The pair ordering is detailed as (O: ordered, X: not ordered) : + * slave master + * slave X O + * master O O + */ + +#define MB_GROUP_ALL 0 +#define RCU_MB_GROUP MB_GROUP_ALL + #ifdef RCU_MEMBARRIER extern int has_sys_membarrier; -static inline void smp_mb_light() +static inline void smp_mb_slave(int group) { if (likely(has_sys_membarrier)) barrier(); @@ -173,14 +188,14 @@ static inline void smp_mb_light() #endif #ifdef RCU_MB -static inline void smp_mb_light() +static inline void smp_mb_slave(int group) { smp_mb(); } #endif #ifdef RCU_SIGNAL -static inline void smp_mb_light() +static inline void smp_mb_slave(int group) { barrier(); } @@ -255,9 +270,9 @@ static inline void _rcu_read_lock(void) _STORE_SHARED(rcu_reader.ctr, _LOAD_SHARED(rcu_gp_ctr)); /* * Set active readers count for outermost nesting level before - * accessing the pointer. See smp_mb_heavy(). + * accessing the pointer. See smp_mb_master(). */ - smp_mb_light(); + smp_mb_slave(RCU_MB_GROUP); } else { _STORE_SHARED(rcu_reader.ctr, tmp + RCU_GP_COUNT); } @@ -270,13 +285,13 @@ static inline void _rcu_read_unlock(void) tmp = rcu_reader.ctr; /* * Finish using rcu before decrementing the pointer. - * See smp_mb_heavy(). + * See smp_mb_master(). */ if (likely((tmp & RCU_GP_CTR_NEST_MASK) == RCU_GP_COUNT)) { - smp_mb_light(); + smp_mb_slave(RCU_MB_GROUP); _STORE_SHARED(rcu_reader.ctr, rcu_reader.ctr - RCU_GP_COUNT); /* write rcu_reader.ctr before read futex */ - smp_mb_light(); + smp_mb_slave(RCU_MB_GROUP); wake_up_gp(); } else { _STORE_SHARED(rcu_reader.ctr, rcu_reader.ctr - RCU_GP_COUNT); diff --git a/urcu.c b/urcu.c index ffdab3c..5e8c612 100644 --- a/urcu.c +++ b/urcu.c @@ -121,7 +121,7 @@ static void mutex_unlock(pthread_mutex_t *mutex) } #ifdef RCU_MEMBARRIER -static void smp_mb_heavy(void) +static void smp_mb_master(int group) { if (likely(has_sys_membarrier)) membarrier(MEMBARRIER_EXPEDITED); @@ -131,7 +131,7 @@ static void smp_mb_heavy(void) #endif #ifdef RCU_MB -static void smp_mb_heavy(void) +static void smp_mb_master(int group) { smp_mb(); } @@ -181,7 +181,7 @@ static void force_mb_all_readers(void) smp_mb(); /* read ->need_mb before ending the barrier */ } -static void smp_mb_heavy(void) +static void smp_mb_master(int group) { force_mb_all_readers(); } @@ -193,7 +193,7 @@ static void smp_mb_heavy(void) static void wait_gp(void) { /* Read reader_gp before read futex */ - smp_mb_heavy(); + smp_mb_master(RCU_MB_GROUP); if (uatomic_read(&gp_futex) == -1) futex_async(&gp_futex, FUTEX_WAIT, -1, NULL, NULL, 0); @@ -230,7 +230,7 @@ void update_counter_and_wait(void) if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { uatomic_dec(&gp_futex); /* Write futex before read reader_gp */ - smp_mb_heavy(); + smp_mb_master(RCU_MB_GROUP); } list_for_each_entry_safe(index, tmp, ®istry, head) { @@ -242,7 +242,7 @@ void update_counter_and_wait(void) if (list_empty(®istry)) { if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { /* Read reader_gp before write futex */ - smp_mb_heavy(); + smp_mb_master(RCU_MB_GROUP); uatomic_set(&gp_futex, 0); } break; @@ -260,7 +260,7 @@ void update_counter_and_wait(void) if (list_empty(®istry)) { if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { /* Read reader_gp before write futex */ - smp_mb_heavy(); + smp_mb_master(RCU_MB_GROUP); uatomic_set(&gp_futex, 0); } break; @@ -270,7 +270,7 @@ void update_counter_and_wait(void) wait_gp(); break; /* only escape switch */ case KICK_READER_LOOPS: - smp_mb_heavy(); + smp_mb_master(RCU_MB_GROUP); wait_loops = 0; break; /* only escape switch */ default: @@ -294,7 +294,7 @@ void synchronize_rcu(void) * where new ptr points to. Must be done within rcu_gp_lock because it * iterates on reader threads.*/ /* Write new ptr before changing the qparity */ - smp_mb_heavy(); + smp_mb_master(RCU_MB_GROUP); /* * Wait for previous parity to be empty of readers. @@ -324,7 +324,7 @@ void synchronize_rcu(void) /* Finish waiting for reader threads before letting the old ptr being * freed. Must be done within rcu_gp_lock because it iterates on reader * threads. */ - smp_mb_heavy(); + smp_mb_master(RCU_MB_GROUP); out: mutex_unlock(&rcu_gp_lock); } -- 2.34.1