X-Git-Url: http://git.liburcu.org/?p=userspace-rcu.git;a=blobdiff_plain;f=urcu.c;h=33e35e1d36a722cb2de2f74e8f3a15c8327f3687;hp=2339bc63c872c6a4826d7a52e8d064d85130c0df;hb=f6d1a94fb64e9beeaf4558f12c157784831d9084;hpb=bc2433a9853a945a825c244e9ccfe341b73b2ceb diff --git a/urcu.c b/urcu.c index 2339bc6..33e35e1 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 +36,30 @@ #include #include +#include "urcu/wfqueue.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 + * rcu_active_readers count to memory (there is no barrier in the reader + * per-se), kick it after 10 loops waiting for it. + */ +#define KICK_READER_LOOPS 10 + +/* + * Active attempts to check for reader Q.S. before calling futex(). + */ +#define RCU_QS_ACTIVE_ATTEMPTS 100 #ifdef RCU_MEMBARRIER static int init_done; @@ -77,11 +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_GLOBAL(struct rcu_reader, rcu_reader); #ifdef DEBUG_YIELD unsigned int yield_active; -unsigned int __thread rand_yield; +__DEFINE_URCU_TLS_GLOBAL(unsigned int, rand_yield); #endif static CDS_LIST_HEAD(registry); @@ -92,20 +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); @@ -118,16 +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(has_sys_membarrier)) membarrier(MEMBARRIER_EXPEDITED); else cmm_smp_mb(); @@ -205,8 +218,11 @@ static void wait_gp(void) void update_counter_and_wait(void) { CDS_LIST_HEAD(qsreaders); - int wait_loops = 0; + unsigned int wait_loops = 0; struct rcu_reader *index, *tmp; +#ifdef HAS_INCOHERENT_CACHES + unsigned int wait_gp_loops = 0; +#endif /* HAS_INCOHERENT_CACHES */ /* Switch parity: 0 -> 1, 1 -> 0 */ CMM_STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE); @@ -228,14 +244,15 @@ void update_counter_and_wait(void) cmm_smp_mb(); /* - * Wait for each thread rcu_reader.ctr count to become 0. + * Wait for each thread URCU_TLS(rcu_reader).ctr count to become 0. */ for (;;) { - wait_loops++; - if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) { + if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { uatomic_dec(&gp_futex); /* Write futex before read reader_gp */ smp_mb_master(RCU_MB_GROUP); + } else { + wait_loops++; } cds_list_for_each_entry_safe(index, tmp, ®istry, node) { @@ -245,14 +262,14 @@ void update_counter_and_wait(void) #ifndef HAS_INCOHERENT_CACHES 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 */ smp_mb_master(RCU_MB_GROUP); uatomic_set(&gp_futex, 0); } break; } else { - if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) + if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) wait_gp(); else caa_cpu_relax(); @@ -260,25 +277,25 @@ 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) { + if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { /* Read reader_gp before write futex */ smp_mb_master(RCU_MB_GROUP); uatomic_set(&gp_futex, 0); } break; } else { - switch (wait_loops) { - case RCU_QS_ACTIVE_ATTEMPTS: - wait_gp(); - break; /* only escape switch */ - case KICK_READER_LOOPS: + if (wait_gp_loops == KICK_READER_LOOPS) { smp_mb_master(RCU_MB_GROUP); - wait_loops = 0; - break; /* only escape switch */ - default: + wait_gp_loops = 0; + } + if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { + wait_gp(); + wait_gp_loops++; + } else { caa_cpu_relax(); } } @@ -311,7 +328,7 @@ 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 rcu_gp_ctr. + * URCU_TLS(rcu_reader).ctr before store to rcu_gp_ctr. */ cmm_barrier(); @@ -351,20 +368,20 @@ 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); } @@ -388,7 +405,7 @@ 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(); } @@ -413,10 +430,8 @@ 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) @@ -425,15 +440,15 @@ 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"