X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu.c;h=e401d8dc75d34bf04d2e62da56df3cc08f0d470d;hp=b8c80ab39ab3daf54a9f25d6ce3bd004a312c5e3;hb=e6d6e2dc86bd63c7e702f68ffdb1e5a6ef723abc;hpb=27b012e271a82b9a0d94543688904f207cd154ea diff --git a/urcu.c b/urcu.c index b8c80ab..e401d8d 100644 --- a/urcu.c +++ b/urcu.c @@ -1,7 +1,19 @@ +/* + * urcu.c + * + * Userspace RCU library + * + * Copyright February 2009 - Mathieu Desnoyers + * + * Distributed under GPLv2 + */ + #include #include #include #include +#include +#include #include "urcu.h" @@ -17,13 +29,34 @@ int __thread urcu_active_readers[2]; struct reader_data { pthread_t tid; - int **urcu_active_readers; + int *urcu_active_readers; }; static struct reader_data *reader_data; static int num_readers, alloc_readers; static int sig_done; +void rcu_write_lock(void) +{ + int ret; + ret = pthread_mutex_lock(&urcu_mutex); + if (ret) { + perror("Error in pthread mutex lock"); + exit(-1); + } +} + +void rcu_write_unlock(void) +{ + int ret; + + ret = pthread_mutex_unlock(&urcu_mutex); + if (ret) { + perror("Error in pthread mutex unlock"); + exit(-1); + } +} + /* * called with urcu_mutex held. */ @@ -36,40 +69,39 @@ static int switch_next_urcu_qparity(void) static void force_mb_all_threads(void) { - pthread_t *index; + struct reader_data *index; /* * Ask for each threads to execute a mb() so we can consider the * compiler barriers around rcu read lock as real memory barriers. */ if (!reader_data) return; - sigtask = TASK_FORCE_MB; sig_done = 0; - mb(); /* write sig_done and sigtask before sending the signals */ + mb(); /* write sig_done before sending the signals */ for (index = reader_data; index < reader_data + num_readers; index++) - pthread_kill(*index, SIGURCU); + pthread_kill(index->tid, SIGURCU); /* * Wait for sighandler (and thus mb()) to execute on every thread. * BUSY-LOOP. */ while (sig_done < num_readers) barrier(); - mb(); /* read sig_done before writing sigtask */ - sigtask = TASK_NONE; + mb(); /* read sig_done before ending the barrier */ } void wait_for_quiescent_state(int parity) { + struct reader_data *index; if (!reader_data) return; /* Wait for each thread urcu_active_readers count to become 0. */ - for (index = readers_data; index < reader_data + num_readers; index++) { + for (index = reader_data; index < reader_data + num_readers; index++) { /* * BUSY-LOOP. */ - while (*index->urcu_active_readers != 0) + while (index->urcu_active_readers[parity] != 0) barrier(); } /* @@ -83,18 +115,13 @@ void wait_for_quiescent_state(int parity) /* * Return old pointer, OK to free, no more reference exist. + * Called under rcu_write_lock. */ void *urcu_publish_content(void **ptr, void *new) { - int ret, prev_parity; + int prev_parity; void *oldptr; - ret = pthread_mutex_lock(&urcu_mutex); - if (ret) { - perror("Error in %s pthread mutex lock", __func__); - exit(-1); - } - /* * We can publish the new pointer before we change the current qparity. * Readers seeing the new pointer while being in the previous qparity @@ -107,9 +134,9 @@ void *urcu_publish_content(void **ptr, void *new) */ oldptr = *ptr; *ptr = new; - wmb(); /* Write ptr before changing the qparity */ /* All threads should read qparity before ptr */ - force_rmb_all_threads(); + /* Write ptr before changing the qparity */ + force_mb_all_threads(); prev_parity = switch_next_urcu_qparity(); /* @@ -120,25 +147,20 @@ void *urcu_publish_content(void **ptr, void *new) * Deleting old data is ok ! */ - ret = pthread_mutex_unlock(&urcu_mutex); - if (ret) { - perror("Error in %s pthread mutex lock", __func__); - exit(-1); - } return oldptr; } void urcu_add_reader(pthread_t id) { + struct reader_data *oldarray; + if (!reader_data) { alloc_readers = INIT_NUM_THREADS; - num_readers = 1; + num_readers = 0; reader_data = malloc(sizeof(struct reader_data) * alloc_readers); - return; } if (alloc_readers < num_readers + 1) { - pthread_t *oldarray; oldarray = reader_data; reader_data = malloc(sizeof(struct reader_data) * (alloc_readers << 1)); @@ -163,7 +185,7 @@ void urcu_remove_reader(pthread_t id) assert(reader_data != NULL); for (index = reader_data; index < reader_data + num_readers; index++) { - if (index->tid == id) { + if (pthread_equal(index->tid, id)) { memcpy(index, &reader_data[num_readers - 1], sizeof(struct reader_data)); reader_data[num_readers - 1].tid = 0; @@ -178,45 +200,19 @@ void urcu_remove_reader(pthread_t id) void urcu_register_thread(void) { - pthread_t self = pthread_self(); - - ret = pthread_mutex_lock(&urcu_mutex); - if (ret) { - perror("Error in %s pthread mutex lock", __func__); - exit(-1); - } - - urcu_add_reader(self); - - - ret = pthread_mutex_unlock(&urcu_mutex); - if (ret) { - perror("Error in %s pthread mutex unlock", __func__); - exit(-1); - } + rcu_write_lock(); + urcu_add_reader(pthread_self()); + rcu_write_unlock(); } -void urcu_register_thread(void) +void urcu_unregister_thread(void) { - pthread_t self = pthread_self(); - - ret = pthread_mutex_lock(&urcu_mutex); - if (ret) { - perror("Error in %s pthread mutex lock", __func__); - exit(-1); - } - - urcu_remove_reader(self); - - ret = pthread_mutex_unlock(&urcu_mutex); - if (ret) { - perror("Error in %s pthread mutex unlock", __func__); - exit(-1); - } - + rcu_write_lock(); + urcu_remove_reader(pthread_self()); + rcu_write_unlock(); } -void handler(int signo, siginfo_t *siginfo, void *context) +void sigurcu_handler(int signo, siginfo_t *siginfo, void *context) { mb(); atomic_inc(&sig_done); @@ -229,8 +225,8 @@ void __attribute__((constructor)) urcu_init(void) act.sa_sigaction = sigurcu_handler; ret = sigaction(SIGURCU, &act, NULL); - if (!ret) { - perror("Error in %s sigaction", __func__); + if (ret) { + perror("Error in sigaction"); exit(-1); } } @@ -241,8 +237,8 @@ void __attribute__((destructor)) urcu_exit(void) int ret; ret = sigaction(SIGURCU, NULL, &act); - if (!ret) { - perror("Error in %s sigaction", __func__); + if (ret) { + perror("Error in sigaction"); exit(-1); } assert(act.sa_sigaction == sigurcu_handler);