*/
#define RCU_QS_ACTIVE_ATTEMPTS 100
+static
+void __attribute__((constructor)) rcu_bp_init(void);
+static
void __attribute__((destructor)) rcu_bp_exit(void);
static pthread_mutex_t rcu_gp_lock = PTHREAD_MUTEX_INITIALIZER;
+static pthread_mutex_t init_lock = PTHREAD_MUTEX_INITIALIZER;
+static int initialized;
+
+static pthread_key_t urcu_bp_key;
+
#ifdef DEBUG_YIELD
unsigned int rcu_yield_active;
DEFINE_URCU_TLS(unsigned int, rcu_rand_yield);
struct registry_chunk {
size_t data_len; /* data length */
- size_t used; /* data used */
+ size_t used; /* amount of data used */
struct cds_list_head node; /* chunk_list node */
char data[];
};
/* Saved fork signal mask, protected by rcu_gp_lock */
static sigset_t saved_fork_signal_mask;
-static void rcu_gc_registry(void);
-
static void mutex_lock(pthread_mutex_t *mutex)
{
int ret;
/* Write new ptr before changing the qparity */
cmm_smp_mb();
- /* Remove old registry elements */
- rcu_gc_registry();
-
/*
* Wait for readers to observe original parity or be quiescent.
*/
void add_thread(void)
{
struct rcu_reader *rcu_reader_reg;
+ int ret;
rcu_reader_reg = arena_alloc(®istry_arena);
if (!rcu_reader_reg)
abort();
+ ret = pthread_setspecific(urcu_bp_key, rcu_reader_reg);
+ if (ret)
+ abort();
/* Add to registry */
rcu_reader_reg->tid = pthread_self();
URCU_TLS(rcu_reader) = rcu_reader_reg;
}
-/* Called with signals off and mutex locked */
-static void rcu_gc_registry(void)
+/* Called with mutex locked */
+static
+void cleanup_thread(struct registry_chunk *chunk,
+ struct rcu_reader *rcu_reader_reg)
+{
+ rcu_reader_reg->ctr = 0;
+ cds_list_del(&rcu_reader_reg->node);
+ rcu_reader_reg->tid = 0;
+ rcu_reader_reg->alloc = 0;
+ chunk->used -= sizeof(struct rcu_reader);
+}
+
+static
+struct registry_chunk *find_chunk(struct rcu_reader *rcu_reader_reg)
{
struct registry_chunk *chunk;
- struct rcu_reader *rcu_reader_reg;
cds_list_for_each_entry(chunk, ®istry_arena.chunk_list, node) {
- for (rcu_reader_reg = (struct rcu_reader *) &chunk->data[0];
- rcu_reader_reg < (struct rcu_reader *) &chunk->data[chunk->data_len];
- rcu_reader_reg++) {
- pthread_t tid;
- int ret;
+ if (rcu_reader_reg < (struct rcu_reader *) &chunk->data[0])
+ continue;
+ if (rcu_reader_reg >= (struct rcu_reader *) &chunk->data[chunk->data_len])
+ continue;
+ return chunk;
+ }
+ return NULL;
+}
- if (!rcu_reader_reg->alloc)
- continue;
- tid = rcu_reader_reg->tid;
- ret = pthread_kill(tid, 0);
- assert(ret != EINVAL);
- if (ret == ESRCH) {
- cds_list_del(&rcu_reader_reg->node);
- rcu_reader_reg->ctr = 0;
- rcu_reader_reg->alloc = 0;
- chunk->used -= sizeof(struct rcu_reader);
- }
+/* Called with signals off and mutex locked */
+static
+void remove_thread(void)
+{
+ struct rcu_reader *rcu_reader_reg;
- }
- }
+ rcu_reader_reg = URCU_TLS(rcu_reader);
+ cleanup_thread(find_chunk(rcu_reader_reg), rcu_reader_reg);
+ URCU_TLS(rcu_reader) = NULL;
}
/* Disable signals, take mutex, add to registry */
int ret;
ret = sigfillset(&newmask);
- assert(!ret);
+ if (ret)
+ abort();
ret = pthread_sigmask(SIG_BLOCK, &newmask, &oldmask);
- assert(!ret);
+ if (ret)
+ abort();
/*
* Check if a signal concurrently registered our thread since
- * the check in rcu_read_lock(). */
+ * the check in rcu_read_lock().
+ */
if (URCU_TLS(rcu_reader))
goto end;
+ /*
+ * Take care of early registration before urcu_bp constructor.
+ */
+ rcu_bp_init();
+
mutex_lock(&rcu_gp_lock);
add_thread();
mutex_unlock(&rcu_gp_lock);
end:
ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
- assert(!ret);
+ if (ret)
+ abort();
+}
+
+/* Disable signals, take mutex, remove from registry */
+static
+void rcu_bp_unregister(void)
+{
+ sigset_t newmask, oldmask;
+ int ret;
+
+ ret = sigfillset(&newmask);
+ if (ret)
+ abort();
+ ret = pthread_sigmask(SIG_BLOCK, &newmask, &oldmask);
+ if (ret)
+ abort();
+
+ mutex_lock(&rcu_gp_lock);
+ remove_thread();
+ mutex_unlock(&rcu_gp_lock);
+ ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
+ if (ret)
+ abort();
+}
+
+/*
+ * Remove thread from the registry when it exits, and flag it as
+ * destroyed so garbage collection can take care of it.
+ */
+static
+void urcu_bp_thread_exit_notifier(void *rcu_key)
+{
+ assert(rcu_key == URCU_TLS(rcu_reader));
+ rcu_bp_unregister();
+}
+
+static
+void rcu_bp_init(void)
+{
+ mutex_lock(&init_lock);
+ if (!initialized) {
+ int ret;
+
+ ret = pthread_key_create(&urcu_bp_key,
+ urcu_bp_thread_exit_notifier);
+ if (ret)
+ abort();
+ initialized = 1;
+ }
+ mutex_unlock(&init_lock);
}
+static
void rcu_bp_exit(void)
{
struct registry_chunk *chunk, *tmp;
+ int ret;
cds_list_for_each_entry_safe(chunk, tmp,
®istry_arena.chunk_list, node) {
munmap(chunk, chunk->data_len + sizeof(struct registry_chunk));
}
+ ret = pthread_key_delete(urcu_bp_key);
+ if (ret)
+ abort();
}
/*
assert(!ret);
}
+/*
+ * Prune all entries from registry except our own thread. Fits the Linux
+ * fork behavior. Called with rcu_gp_lock held.
+ */
+static
+void urcu_bp_prune_registry(void)
+{
+ struct registry_chunk *chunk;
+ struct rcu_reader *rcu_reader_reg;
+
+ cds_list_for_each_entry(chunk, ®istry_arena.chunk_list, node) {
+ for (rcu_reader_reg = (struct rcu_reader *) &chunk->data[0];
+ rcu_reader_reg < (struct rcu_reader *) &chunk->data[chunk->data_len];
+ rcu_reader_reg++) {
+ if (!rcu_reader_reg->alloc)
+ continue;
+ if (rcu_reader_reg->tid == pthread_self())
+ continue;
+ cleanup_thread(chunk, rcu_reader_reg);
+ }
+ }
+}
+
void rcu_bp_after_fork_child(void)
{
sigset_t oldmask;
int ret;
- rcu_gc_registry();
+ urcu_bp_prune_registry();
oldmask = saved_fork_signal_mask;
mutex_unlock(&rcu_gp_lock);
ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
projects / urcu.git / blobdiff