From c13c2e55160906ebe65756d8674558eda123912d Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Mon, 6 May 2013 10:30:57 -0400 Subject: [PATCH] urcu-bp: introduce struct urcu_gp Make urcu-bp similar to urcu-qsbr and other urcu flavors. Signed-off-by: Mathieu Desnoyers --- urcu-bp.c | 12 +++--------- urcu/map/urcu-bp.h | 3 +-- urcu/static/urcu-bp.h | 24 +++++++++++++++--------- 3 files changed, 19 insertions(+), 20 deletions(-) diff --git a/urcu-bp.c b/urcu-bp.c index 8207a41..ef1e687 100644 --- a/urcu-bp.c +++ b/urcu-bp.c @@ -109,13 +109,7 @@ unsigned int rcu_yield_active; DEFINE_URCU_TLS(unsigned int, rcu_rand_yield); #endif -/* - * Global grace period counter. - * Contains the current RCU_GP_CTR_PHASE. - * Also has a RCU_GP_COUNT of 1, to accelerate the reader fast path. - * Written to only by writer with mutex taken. Read by both writer and readers. - */ -unsigned long rcu_gp_ctr = RCU_GP_COUNT; +struct rcu_gp rcu_gp = { .ctr = RCU_GP_COUNT }; /* * Pointer to registry elements. Written to only by each individual reader. Read @@ -174,7 +168,7 @@ static void wait_for_readers(struct cds_list_head *input_readers, /* * Wait for each thread URCU_TLS(rcu_reader).ctr to either * indicate quiescence (not nested), or observe the current - * rcu_gp_ctr value. + * rcu_gp.ctr value. */ for (;;) { wait_loops++; @@ -250,7 +244,7 @@ void synchronize_rcu(void) cmm_smp_mb(); /* Switch parity: 0 -> 1, 1 -> 0 */ - CMM_STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE); + CMM_STORE_SHARED(rcu_gp.ctr, rcu_gp.ctr ^ RCU_GP_CTR_PHASE); /* * Must commit qparity update to memory before waiting for other parity diff --git a/urcu/map/urcu-bp.h b/urcu/map/urcu-bp.h index 8c819a6..92863fe 100644 --- a/urcu/map/urcu-bp.h +++ b/urcu/map/urcu-bp.h @@ -46,8 +46,7 @@ #define rcu_exit rcu_exit_bp #define synchronize_rcu synchronize_rcu_bp #define rcu_reader rcu_reader_bp -#define rcu_gp_ctr rcu_gp_ctr_bp -#define rcu_gp_futex rcu_gp_futex_bp /* unused */ +#define rcu_gp rcu_gp_bp #define get_cpu_call_rcu_data get_cpu_call_rcu_data_bp #define get_call_rcu_thread get_call_rcu_thread_bp diff --git a/urcu/static/urcu-bp.h b/urcu/static/urcu-bp.h index 2f36520..1052c44 100644 --- a/urcu/static/urcu-bp.h +++ b/urcu/static/urcu-bp.h @@ -130,12 +130,18 @@ static inline void rcu_debug_yield_init(void) */ extern void rcu_bp_register(void); -/* - * Global quiescent period counter with low-order bits unused. - * Using a int rather than a char to eliminate false register dependencies - * causing stalls on some architectures. - */ -extern unsigned long rcu_gp_ctr; +struct rcu_gp { + /* + * Global grace period counter. + * Contains the current RCU_GP_CTR_PHASE. + * Also has a RCU_GP_COUNT of 1, to accelerate the reader fast path. + * Written to only by writer with mutex taken. + * Read by both writer and readers. + */ + unsigned long ctr; +} __attribute__((aligned(CAA_CACHE_LINE_SIZE))); + +extern struct rcu_gp rcu_gp; struct rcu_reader { /* Data used by both reader and synchronize_rcu() */ @@ -166,13 +172,13 @@ static inline enum rcu_state rcu_reader_state(unsigned long *ctr) v = CMM_LOAD_SHARED(*ctr); if (!(v & RCU_GP_CTR_NEST_MASK)) return RCU_READER_INACTIVE; - if (!((v ^ rcu_gp_ctr) & RCU_GP_CTR_PHASE)) + if (!((v ^ rcu_gp.ctr) & RCU_GP_CTR_PHASE)) return RCU_READER_ACTIVE_CURRENT; return RCU_READER_ACTIVE_OLD; } /* - * Helper for _rcu_read_lock(). The format of rcu_gp_ctr (as well as + * Helper for _rcu_read_lock(). The format of rcu_gp.ctr (as well as * the per-thread rcu_reader.ctr) has the upper bits containing a count of * _rcu_read_lock() nesting, and a lower-order bit that contains either zero * or RCU_GP_CTR_PHASE. The smp_mb_slave() ensures that the accesses in @@ -181,7 +187,7 @@ static inline enum rcu_state rcu_reader_state(unsigned long *ctr) static inline void _rcu_read_lock_update(unsigned long tmp) { if (caa_likely(!(tmp & RCU_GP_CTR_NEST_MASK))) { - _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, _CMM_LOAD_SHARED(rcu_gp_ctr)); + _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, _CMM_LOAD_SHARED(rcu_gp.ctr)); cmm_smp_mb(); } else _CMM_STORE_SHARED(URCU_TLS(rcu_reader)->ctr, tmp + RCU_GP_COUNT); -- 2.34.1