X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu.c;h=2d5c510aa6744418c5557d642b451e0afae415cd;hp=be6d4bdfc55b32d624011280c972d6f2772f2853;hb=708d89f0b396d20522fe87cc80d91072bb9fcb02;hpb=3a71751ee010b48e1a1fa7081617ec6f82d5c0ba diff --git a/urcu.c b/urcu.c index be6d4bd..2d5c510 100644 --- a/urcu.c +++ b/urcu.c @@ -25,6 +25,7 @@ #define _BSD_SOURCE #define _GNU_SOURCE +#define _LGPL_SOURCE #include #include #include @@ -35,11 +36,18 @@ #include #include +#include "urcu/wfcqueue.h" #include "urcu/map/urcu.h" - #include "urcu/static/urcu.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.h" +#define _LGPL_SOURCE /* * If a reader is really non-cooperative and refuses to commit its @@ -55,7 +63,7 @@ #ifdef RCU_MEMBARRIER static int init_done; -int has_sys_membarrier; +int rcu_has_sys_membarrier; void __attribute__((constructor)) rcu_init(void); #endif @@ -75,7 +83,7 @@ void __attribute__((destructor)) rcu_exit(void); static pthread_mutex_t rcu_gp_lock = PTHREAD_MUTEX_INITIALIZER; -int32_t gp_futex; +int32_t rcu_gp_futex; /* * Global grace period counter. @@ -89,11 +97,11 @@ unsigned long rcu_gp_ctr = RCU_GP_COUNT; * 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; +unsigned int rcu_yield_active; +DEFINE_URCU_TLS(unsigned int, rcu_rand_yield); #endif static CDS_LIST_HEAD(registry); @@ -104,20 +112,15 @@ 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 (CMM_LOAD_SHARED(rcu_reader.need_mb)) { + if (ret != EBUSY && ret != EINTR) + urcu_die(ret); + if (CMM_LOAD_SHARED(URCU_TLS(rcu_reader).need_mb)) { cmm_smp_mb(); - _CMM_STORE_SHARED(rcu_reader.need_mb, 0); + _CMM_STORE_SHARED(URCU_TLS(rcu_reader).need_mb, 0); cmm_smp_mb(); } poll(NULL,0,10); @@ -130,16 +133,14 @@ 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); } #ifdef RCU_MEMBARRIER static void smp_mb_master(int group) { - if (likely(has_sys_membarrier)) + if (caa_likely(rcu_has_sys_membarrier)) membarrier(MEMBARRIER_EXPEDITED); else cmm_smp_mb(); @@ -209,43 +210,26 @@ static void wait_gp(void) { /* Read reader_gp before read futex */ smp_mb_master(RCU_MB_GROUP); - if (uatomic_read(&gp_futex) == -1) - futex_async(&gp_futex, FUTEX_WAIT, -1, + if (uatomic_read(&rcu_gp_futex) == -1) + futex_async(&rcu_gp_futex, FUTEX_WAIT, -1, NULL, NULL, 0); } -void update_counter_and_wait(void) +static void wait_for_readers(void) { CDS_LIST_HEAD(qsreaders); int wait_loops = 0; struct rcu_reader *index, *tmp; - /* Switch parity: 0 -> 1, 1 -> 0 */ - CMM_STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE); - - /* - * Must commit rcu_gp_ctr update to memory before waiting for 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. - */ - cmm_barrier(); - /* - * - * Adding a cmm_smp_mb() which is _not_ formally required, but makes the - * model easier to understand. It does not have a big performance impact - * anyway, given this is the write-side. - */ - cmm_smp_mb(); - - /* - * Wait for each thread rcu_reader.ctr count to become 0. + * Wait for each thread URCU_TLS(rcu_reader).ctr to either + * indicate quiescence (not nested), or observe the current + * rcu_gp_ctr value. */ for (;;) { wait_loops++; if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { - uatomic_dec(&gp_futex); + uatomic_dec(&rcu_gp_futex); /* Write futex before read reader_gp */ smp_mb_master(RCU_MB_GROUP); } @@ -260,7 +244,7 @@ void update_counter_and_wait(void) if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { /* Read reader_gp before write futex */ smp_mb_master(RCU_MB_GROUP); - uatomic_set(&gp_futex, 0); + uatomic_set(&rcu_gp_futex, 0); } break; } else { @@ -272,13 +256,14 @@ void update_counter_and_wait(void) #else /* #ifndef HAS_INCOHERENT_CACHES */ /* * BUSY-LOOP. Force the reader thread to commit its - * rcu_reader.ctr update to memory if we wait for too long. + * URCU_TLS(rcu_reader).ctr update to memory if we wait + * for too long. */ if (cds_list_empty(®istry)) { if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { /* Read reader_gp before write futex */ smp_mb_master(RCU_MB_GROUP); - uatomic_set(&gp_futex, 0); + uatomic_set(&rcu_gp_futex, 0); } break; } else { @@ -314,16 +299,16 @@ void synchronize_rcu(void) smp_mb_master(RCU_MB_GROUP); /* - * Wait for previous parity to be empty of readers. + * Wait for readers to observe original parity or be quiescent. */ - update_counter_and_wait(); /* 0 -> 1, wait readers in parity 0 */ + wait_for_readers(); /* - * Must finish waiting for quiescent state for parity 0 before + * Must finish waiting for quiescent state for original parity before * 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 rcu_gp_ctr. + * URCU_TLS(rcu_reader).ctr before store to rcu_gp_ctr. */ cmm_barrier(); @@ -334,10 +319,29 @@ 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); + /* - * Wait for previous parity to be empty of readers. + * Must commit rcu_gp_ctr update to memory before waiting for 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. */ - update_counter_and_wait(); /* 1 -> 0, wait readers in parity 1 */ + cmm_barrier(); + + /* + * + * Adding a cmm_smp_mb() which is _not_ formally required, but makes the + * model easier to understand. It does not have a big performance impact + * anyway, given this is the write-side. + */ + cmm_smp_mb(); + + /* + * Wait for readers to observe new parity or be quiescent. + */ + wait_for_readers(); /* Finish waiting for reader threads before letting the old ptr being * freed. Must be done within rcu_gp_lock because it iterates on reader @@ -363,20 +367,20 @@ void rcu_read_unlock(void) void rcu_register_thread(void) { - rcu_reader.tid = pthread_self(); - assert(rcu_reader.need_mb == 0); - assert(!(rcu_reader.ctr & RCU_GP_CTR_NEST_MASK)); + URCU_TLS(rcu_reader).tid = pthread_self(); + assert(URCU_TLS(rcu_reader).need_mb == 0); + assert(!(URCU_TLS(rcu_reader).ctr & RCU_GP_CTR_NEST_MASK)); mutex_lock(&rcu_gp_lock); rcu_init(); /* In case gcc does not support constructor attribute */ - cds_list_add(&rcu_reader.node, ®istry); + cds_list_add(&URCU_TLS(rcu_reader).node, ®istry); mutex_unlock(&rcu_gp_lock); } void rcu_unregister_thread(void) { mutex_lock(&rcu_gp_lock); - cds_list_del(&rcu_reader.node); + cds_list_del(&URCU_TLS(rcu_reader).node); mutex_unlock(&rcu_gp_lock); } @@ -387,7 +391,7 @@ void rcu_init(void) return; init_done = 1; if (!membarrier(MEMBARRIER_EXPEDITED | MEMBARRIER_QUERY)) - has_sys_membarrier = 1; + rcu_has_sys_membarrier = 1; } #endif @@ -400,7 +404,7 @@ static void sigrcu_handler(int signo, siginfo_t *siginfo, void *context) * executed on. */ cmm_smp_mb(); - _CMM_STORE_SHARED(rcu_reader.need_mb, 0); + _CMM_STORE_SHARED(URCU_TLS(rcu_reader).need_mb, 0); cmm_smp_mb(); } @@ -425,10 +429,8 @@ void rcu_init(void) act.sa_flags = SA_SIGINFO | SA_RESTART; sigemptyset(&act.sa_mask); ret = sigaction(SIGRCU, &act, NULL); - if (ret) { - perror("Error in sigaction"); - exit(-1); - } + if (ret) + urcu_die(errno); } void rcu_exit(void) @@ -437,15 +439,15 @@ void rcu_exit(void) int ret; ret = sigaction(SIGRCU, NULL, &act); - if (ret) { - perror("Error in sigaction"); - exit(-1); - } + if (ret) + urcu_die(errno); assert(act.sa_sigaction == sigrcu_handler); assert(cds_list_empty(®istry)); } #endif /* #ifdef RCU_SIGNAL */ +DEFINE_RCU_FLAVOR(rcu_flavor); + #include "urcu-call-rcu-impl.h" #include "urcu-defer-impl.h"