X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu-qsbr.c;h=d3a6849ac04901097783fd0810b7a4aba4bf792c;hp=a239be036d416f68259c0f586f5d0ce7248385e9;hb=ae51baf267fc36ccc259f9287e2750c138ff80bc;hpb=3df2c3288ba01c46fa2c85167df7f03aa52ecc5f diff --git a/urcu-qsbr.c b/urcu-qsbr.c index a239be0..d3a6849 100644 --- a/urcu-qsbr.c +++ b/urcu-qsbr.c @@ -24,6 +24,7 @@ */ #define _GNU_SOURCE +#define _LGPL_SOURCE #include #include #include @@ -34,12 +35,19 @@ #include #include +#include "urcu/wfqueue.h" #include "urcu/map/urcu-qsbr.h" - #define BUILD_QSBR_LIB #include "urcu/static/urcu-qsbr.h" +#include "urcu-pointer.h" +#include "urcu/tls-compat.h" + +#include "urcu-die.h" + /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */ +#undef _LGPL_SOURCE #include "urcu-qsbr.h" +#define _LGPL_SOURCE void __attribute__((destructor)) rcu_exit(void); @@ -61,11 +69,11 @@ unsigned long rcu_gp_ctr = RCU_GP_ONLINE; * Written to only by each individual reader. Read by both the reader and the * writers. */ -struct rcu_reader __thread rcu_reader; +DEFINE_URCU_TLS(struct rcu_reader, rcu_reader); #ifdef DEBUG_YIELD unsigned int yield_active; -unsigned int __thread rand_yield; +DEFINE_URCU_TLS(unsigned int, rand_yield); #endif static CDS_LIST_HEAD(registry); @@ -76,17 +84,12 @@ static void mutex_lock(pthread_mutex_t *mutex) #ifndef DISTRUST_SIGNALS_EXTREME ret = pthread_mutex_lock(mutex); - if (ret) { - perror("Error in pthread mutex lock"); - exit(-1); - } + if (ret) + urcu_die(ret); #else /* #ifndef DISTRUST_SIGNALS_EXTREME */ while ((ret = pthread_mutex_trylock(mutex)) != 0) { - if (ret != EBUSY && ret != EINTR) { - printf("ret = %d, errno = %d\n", ret, errno); - perror("Error in pthread mutex lock"); - exit(-1); - } + if (ret != EBUSY && ret != EINTR) + urcu_die(ret); poll(NULL,0,10); } #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */ @@ -97,10 +100,8 @@ static void mutex_unlock(pthread_mutex_t *mutex) int ret; ret = pthread_mutex_unlock(mutex); - if (ret) { - perror("Error in pthread mutex unlock"); - exit(-1); - } + if (ret) + urcu_die(ret); } /* @@ -134,7 +135,7 @@ static void update_counter_and_wait(void) * quiescent state. Failure to do so could result in the writer * waiting forever while new readers are always accessing data * (no progress). Enforce compiler-order of store to rcu_gp_ctr - * before load rcu_reader ctr. + * before load URCU_TLS(rcu_reader).ctr. */ cmm_barrier(); @@ -150,26 +151,33 @@ static void update_counter_and_wait(void) */ for (;;) { wait_loops++; - if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { - uatomic_dec(&gp_futex); + if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { + uatomic_set(&gp_futex, -1); + /* + * Write futex before write waiting (the other side + * reads them in the opposite order). + */ + cmm_smp_wmb(); + cds_list_for_each_entry(index, ®istry, node) { + _CMM_STORE_SHARED(index->waiting, 1); + } /* Write futex before read reader_gp */ cmm_smp_mb(); } - cds_list_for_each_entry_safe(index, tmp, ®istry, node) { if (!rcu_gp_ongoing(&index->ctr)) cds_list_move(&index->node, &qsreaders); } if (cds_list_empty(®istry)) { - if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { + if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { /* Read reader_gp before write futex */ cmm_smp_mb(); uatomic_set(&gp_futex, 0); } break; } else { - if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { + if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { wait_gp(); } else { #ifndef HAS_INCOHERENT_CACHES @@ -194,21 +202,20 @@ void synchronize_rcu(void) { unsigned long was_online; - was_online = rcu_reader.ctr; + was_online = URCU_TLS(rcu_reader).ctr; /* All threads should read qparity before accessing data structure - * where new ptr points to. - */ - /* Write new ptr before changing the qparity */ - cmm_smp_mb(); - - /* + * where new ptr points to. In the "then" case, rcu_thread_offline + * includes a memory barrier. + * * Mark the writer thread offline to make sure we don't wait for * our own quiescent state. This allows using synchronize_rcu() * in threads registered as readers. */ if (was_online) - CMM_STORE_SHARED(rcu_reader.ctr, 0); + rcu_thread_offline(); + else + cmm_smp_mb(); mutex_lock(&rcu_gp_lock); @@ -225,7 +232,7 @@ void synchronize_rcu(void) * committing next rcu_gp_ctr update to memory. Failure to * do so could result in the writer waiting forever while new * readers are always accessing data (no progress). Enforce - * compiler-order of load rcu_reader ctr before store to + * compiler-order of load URCU_TLS(rcu_reader).ctr before store to * rcu_gp_ctr. */ cmm_barrier(); @@ -249,25 +256,26 @@ out: * freed. */ if (was_online) - _CMM_STORE_SHARED(rcu_reader.ctr, - CMM_LOAD_SHARED(rcu_gp_ctr)); - cmm_smp_mb(); + rcu_thread_online(); + else + cmm_smp_mb(); } #else /* !(CAA_BITS_PER_LONG < 64) */ void synchronize_rcu(void) { unsigned long was_online; - was_online = rcu_reader.ctr; + was_online = URCU_TLS(rcu_reader).ctr; /* * Mark the writer thread offline to make sure we don't wait for * our own quiescent state. This allows using synchronize_rcu() * in threads registered as readers. */ - cmm_smp_mb(); if (was_online) - CMM_STORE_SHARED(rcu_reader.ctr, 0); + rcu_thread_offline(); + else + cmm_smp_mb(); mutex_lock(&rcu_gp_lock); if (cds_list_empty(®istry)) @@ -277,9 +285,9 @@ out: mutex_unlock(&rcu_gp_lock); if (was_online) - _CMM_STORE_SHARED(rcu_reader.ctr, - CMM_LOAD_SHARED(rcu_gp_ctr)); - cmm_smp_mb(); + rcu_thread_online(); + else + cmm_smp_mb(); } #endif /* !(CAA_BITS_PER_LONG < 64) */ @@ -314,11 +322,11 @@ void rcu_thread_online(void) void rcu_register_thread(void) { - rcu_reader.tid = pthread_self(); - assert(rcu_reader.ctr == 0); + URCU_TLS(rcu_reader).tid = pthread_self(); + assert(URCU_TLS(rcu_reader).ctr == 0); mutex_lock(&rcu_gp_lock); - cds_list_add(&rcu_reader.node, ®istry); + cds_list_add(&URCU_TLS(rcu_reader).node, ®istry); mutex_unlock(&rcu_gp_lock); _rcu_thread_online(); } @@ -331,14 +339,20 @@ void rcu_unregister_thread(void) */ _rcu_thread_offline(); mutex_lock(&rcu_gp_lock); - cds_list_del(&rcu_reader.node); + cds_list_del(&URCU_TLS(rcu_reader).node); mutex_unlock(&rcu_gp_lock); } void rcu_exit(void) { - assert(cds_list_empty(®istry)); + /* + * Assertion disabled because call_rcu threads are now rcu + * readers, and left running at exit. + * assert(cds_list_empty(®istry)); + */ } +DEFINE_RCU_FLAVOR(rcu_flavor); + #include "urcu-call-rcu-impl.h" #include "urcu-defer-impl.h"