ck_brlock3
Big-reader locks
Usage
#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);
Library
Concurrency Kit (libck, -lck)
Overview
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 expensive O(n) operation. This is a write-biased lock.
Examples
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;
}
Releases
Unchanged in 5 releases since Debian 8 (Jessie).