FreeBSD Manual Pages
ck_brlock(3) FreeBSD Library Functions Manual ck_brlock(3) NAME ck_brlock_init, ck_brlock_write_lock, ck_brlock_write_unlock, ck_brlock_write_trylock, ck_brlock_read_register, ck_brlock_read_unregister, ck_brlock_read_lock, ck_brlock_read_trylock, ck_brlock_read_unlock -- big-reader locks LIBRARY Concurrency Kit (libck, -lck) SYNOPSIS #include <ck_brlock.h> ck_brlock_t brlock = CK_BRLOCK_INITIALIZER; ck_brlock_reader_t reader = CK_BRLOCK_READER_INITIALIZER; void ck_brlock_init(ck_brlock_t *br); void ck_brlock_write_lock(ck_brlock_t *br); void ck_brlock_write_unlock(ck_brlock_t *br); bool ck_brlock_write_trylock(ck_brlock_t *br, unsigned int factor); void ck_brlock_read_register(ck_brlock_t *br, ck_brlock_reader_t *reader); void ck_brlock_read_unregister(ck_brlock_t *br, ck_brlock_reader_t *reader); void ck_brlock_read_lock(ck_brlock_t *br, ck_brlock_reader_t *reader); bool ck_brlock_read_trylock(ck_brlock_t *br, ck_brlock_reader_t *reader, unsigned int factor); void ck_brlock_read_unlock(ck_brlock_reader_t *reader); DESCRIPTION Big reader locks are distributed reader-writer locks with low latency constant time reader acquisition (with respect to number of concurrent readers). On the other hand, writer acquisitions are a relatively expen- sive O(n) operation. This is a write-biased lock. EXAMPLE static ck_brlock_t lock = CK_BRLOCK_INITIALIZER; static __thread ck_brlock_reader_t reader; static void reader(void) { /* Add our thread as a lock participant. */ ck_brlock_read_register(&lock, &reader); for (;;) { ck_brlock_read_lock(&lock, &reader); /* Read-side critical section. */ ck_brlock_read_unlock(&reader); if (ck_brlock_read_trylock(&lock, &reader, 1) == true) { /* Read-side critical section. */ ck_brlock_read_unlock(&reader); } } return; } static void writer(void) { for (;;) { ck_brlock_write_lock(&lock); /* Write-side critical section. */ ck_brlock_write_unlock(&lock); if (ck_brlock_write_trylock(&lock, 1) == true) { /* Write-side critical section. */ ck_brlock_write_unlock(&lock); } } return; } SEE ALSO ck_bytelock(3), ck_rwlock(3) Additional information available at http://concurrencykit.org/ July 26, 2013.
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | EXAMPLE | SEE ALSO
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