#include <errno.h>
#include <poll.h>
#include <sys/time.h>
-#include <syscall.h>
#include <unistd.h>
+#include <stdint.h>
#include "urcu/futex.h"
#include <urcu/uatomic.h>
#include <urcu/list.h>
#include <urcu/system.h>
+#include <urcu/tls-compat.h>
+#include "urcu-die.h"
/*
* Number of entries in the per-thread defer queue. Must be power of 2.
* Assumes that (void *)-2L is not used often. Used to encode non-aligned
* functions and non-aligned data using extra space.
* We encode the (void *)-2L fct as: -2L, fct, data.
- * We encode the (void *)-2L data as: -2L, fct, data.
+ * We encode the (void *)-2L data as either:
+ * fct | DQ_FCT_BIT, data (if fct is aligned), or
+ * -2L, fct, data (if fct is not aligned).
* Here, DQ_FCT_MARK == ~DQ_FCT_BIT. Required for the test order.
*/
#define DQ_FCT_BIT (1 << 0)
* This is required to permit relinking with newer versions of the library.
*/
-#ifdef DEBUG_RCU
-#define rcu_assert(args...) assert(args)
-#else
-#define rcu_assert(args...)
-#endif
-
/*
* defer queue.
* Contains pointers. Encoded to save space when same callback is often used.
static pthread_mutex_t rcu_defer_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t defer_thread_mutex = PTHREAD_MUTEX_INITIALIZER;
-static int defer_thread_futex;
+static int32_t defer_thread_futex;
+static int32_t defer_thread_stop;
/*
* Written to only by each individual deferer. Read by both the deferer and
* the reclamation tread.
*/
-static struct defer_queue __thread defer_queue;
+static DEFINE_URCU_TLS(struct defer_queue, defer_queue);
static CDS_LIST_HEAD(registry_defer);
static pthread_t tid_defer;
#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);
- }
- pthread_testcancel();
- poll(NULL,0,10);
+ if (ret != EBUSY && ret != EINTR)
+ urcu_die(ret);
+ (void) poll(NULL,0,10);
}
#endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */
}
*/
static void wake_up_defer(void)
{
- if (unlikely(uatomic_read(&defer_thread_futex) == -1)) {
+ if (caa_unlikely(uatomic_read(&defer_thread_futex) == -1)) {
uatomic_set(&defer_thread_futex, 0);
- futex_noasync(&defer_thread_futex, FUTEX_WAKE, 1,
- NULL, NULL, 0);
+ if (futex_noasync(&defer_thread_futex, FUTEX_WAKE, 1,
+ NULL, NULL, 0) < 0)
+ urcu_die(errno);
}
}
static void wait_defer(void)
{
uatomic_dec(&defer_thread_futex);
- cmm_smp_mb(); /* Write futex before read queue */
+ /* Write futex before read queue */
+ /* Write futex before read defer_thread_stop */
+ cmm_smp_mb();
+ if (_CMM_LOAD_SHARED(defer_thread_stop)) {
+ uatomic_set(&defer_thread_futex, 0);
+ pthread_exit(0);
+ }
if (rcu_defer_num_callbacks()) {
cmm_smp_mb(); /* Read queue before write futex */
/* Callbacks are queued, don't wait. */
uatomic_set(&defer_thread_futex, 0);
} else {
cmm_smp_rmb(); /* Read queue before read futex */
- if (uatomic_read(&defer_thread_futex) == -1)
- futex_noasync(&defer_thread_futex, FUTEX_WAIT, -1,
- NULL, NULL, 0);
+ if (uatomic_read(&defer_thread_futex) != -1)
+ return;
+ while (futex_noasync(&defer_thread_futex, FUTEX_WAIT, -1,
+ NULL, NULL, 0)) {
+ switch (errno) {
+ case EWOULDBLOCK:
+ /* Value already changed. */
+ return;
+ case EINTR:
+ /* Retry if interrupted by signal. */
+ break; /* Get out of switch. */
+ default:
+ /* Unexpected error. */
+ urcu_die(errno);
+ }
+ }
}
}
for (i = queue->tail; i != head;) {
cmm_smp_rmb(); /* read head before q[]. */
p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
- if (unlikely(DQ_IS_FCT_BIT(p))) {
+ if (caa_unlikely(DQ_IS_FCT_BIT(p))) {
DQ_CLEAR_FCT_BIT(p);
queue->last_fct_out = p;
p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
- } else if (unlikely(p == DQ_FCT_MARK)) {
+ } else if (caa_unlikely(p == DQ_FCT_MARK)) {
p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
queue->last_fct_out = p;
p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
{
unsigned long head, num_items;
- head = defer_queue.head;
- num_items = head - defer_queue.tail;
- if (unlikely(!num_items))
+ head = URCU_TLS(defer_queue).head;
+ num_items = head - URCU_TLS(defer_queue).tail;
+ if (caa_unlikely(!num_items))
return;
synchronize_rcu();
- rcu_defer_barrier_queue(&defer_queue, head);
+ rcu_defer_barrier_queue(&URCU_TLS(defer_queue), head);
}
void rcu_defer_barrier_thread(void)
index->last_head = CMM_LOAD_SHARED(index->head);
num_items += index->last_head - index->tail;
}
- if (likely(!num_items)) {
+ if (caa_likely(!num_items)) {
/*
* We skip the grace period because there are no queued
* callbacks to execute.
/*
* _defer_rcu - Queue a RCU callback.
*/
-void _defer_rcu(void (*fct)(void *p), void *p)
+static void _defer_rcu(void (*fct)(void *p), void *p)
{
unsigned long head, tail;
* Head is only modified by ourself. Tail can be modified by reclamation
* thread.
*/
- head = defer_queue.head;
- tail = CMM_LOAD_SHARED(defer_queue.tail);
+ head = URCU_TLS(defer_queue).head;
+ tail = CMM_LOAD_SHARED(URCU_TLS(defer_queue).tail);
/*
* If queue is full, or reached threshold. Empty queue ourself.
* Worse-case: must allow 2 supplementary entries for fct pointer.
*/
- if (unlikely(head - tail >= DEFER_QUEUE_SIZE - 2)) {
+ if (caa_unlikely(head - tail >= DEFER_QUEUE_SIZE - 2)) {
assert(head - tail <= DEFER_QUEUE_SIZE);
rcu_defer_barrier_thread();
- assert(head - CMM_LOAD_SHARED(defer_queue.tail) == 0);
+ assert(head - CMM_LOAD_SHARED(URCU_TLS(defer_queue).tail) == 0);
}
- if (unlikely(defer_queue.last_fct_in != fct)) {
- defer_queue.last_fct_in = fct;
- if (unlikely(DQ_IS_FCT_BIT(fct) || fct == DQ_FCT_MARK)) {
- /*
- * If the function to encode is not aligned or the
- * marker, write DQ_FCT_MARK followed by the function
- * pointer.
- */
- _CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
+ /*
+ * Encode:
+ * if the function is not changed and the data is aligned and it is
+ * not the marker:
+ * store the data
+ * otherwise if the function is aligned and its not the marker:
+ * store the function with DQ_FCT_BIT
+ * store the data
+ * otherwise:
+ * store the marker (DQ_FCT_MARK)
+ * store the function
+ * store the data
+ *
+ * Decode: see the comments before 'struct defer_queue'
+ * or the code in rcu_defer_barrier_queue().
+ */
+ if (caa_unlikely(URCU_TLS(defer_queue).last_fct_in != fct
+ || DQ_IS_FCT_BIT(p)
+ || p == DQ_FCT_MARK)) {
+ URCU_TLS(defer_queue).last_fct_in = fct;
+ if (caa_unlikely(DQ_IS_FCT_BIT(fct) || fct == DQ_FCT_MARK)) {
+ _CMM_STORE_SHARED(URCU_TLS(defer_queue).q[head++ & DEFER_QUEUE_MASK],
DQ_FCT_MARK);
- _CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
+ _CMM_STORE_SHARED(URCU_TLS(defer_queue).q[head++ & DEFER_QUEUE_MASK],
fct);
} else {
DQ_SET_FCT_BIT(fct);
- _CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
- fct);
- }
- } else {
- if (unlikely(DQ_IS_FCT_BIT(p) || p == DQ_FCT_MARK)) {
- /*
- * If the data to encode is not aligned or the marker,
- * write DQ_FCT_MARK followed by the function pointer.
- */
- _CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
- DQ_FCT_MARK);
- _CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
+ _CMM_STORE_SHARED(URCU_TLS(defer_queue).q[head++ & DEFER_QUEUE_MASK],
fct);
}
}
- _CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK], p);
+ _CMM_STORE_SHARED(URCU_TLS(defer_queue).q[head++ & DEFER_QUEUE_MASK], p);
cmm_smp_wmb(); /* Publish new pointer before head */
/* Write q[] before head. */
- CMM_STORE_SHARED(defer_queue.head, head);
+ CMM_STORE_SHARED(URCU_TLS(defer_queue).head, head);
cmm_smp_mb(); /* Write queue head before read futex */
/*
* Wake-up any waiting defer thread.
wake_up_defer();
}
-void *thr_defer(void *args)
+static void *thr_defer(void *args)
{
for (;;) {
- pthread_testcancel();
/*
* "Be green". Don't wake up the CPU if there is no RCU work
* to perform whatsoever. Aims at saving laptop battery life by
*/
wait_defer();
/* Sleeping after wait_defer to let many callbacks enqueue */
- poll(NULL,0,100); /* wait for 100ms */
+ (void) poll(NULL,0,100); /* wait for 100ms */
rcu_defer_barrier();
}
int ret;
void *tret;
- pthread_cancel(tid_defer);
+ _CMM_STORE_SHARED(defer_thread_stop, 1);
+ /* Store defer_thread_stop before testing futex */
+ cmm_smp_mb();
wake_up_defer();
+
ret = pthread_join(tid_defer, &tret);
assert(!ret);
+
+ CMM_STORE_SHARED(defer_thread_stop, 0);
+ /* defer thread should always exit when futex value is 0 */
+ assert(uatomic_read(&defer_thread_futex) == 0);
}
int rcu_defer_register_thread(void)
{
int was_empty;
- assert(defer_queue.last_head == 0);
- assert(defer_queue.q == NULL);
- defer_queue.q = malloc(sizeof(void *) * DEFER_QUEUE_SIZE);
- if (!defer_queue.q)
+ assert(URCU_TLS(defer_queue).last_head == 0);
+ assert(URCU_TLS(defer_queue).q == NULL);
+ URCU_TLS(defer_queue).q = malloc(sizeof(void *) * DEFER_QUEUE_SIZE);
+ if (!URCU_TLS(defer_queue).q)
return -ENOMEM;
mutex_lock_defer(&defer_thread_mutex);
mutex_lock_defer(&rcu_defer_mutex);
was_empty = cds_list_empty(®istry_defer);
- cds_list_add(&defer_queue.list, ®istry_defer);
+ cds_list_add(&URCU_TLS(defer_queue).list, ®istry_defer);
mutex_unlock(&rcu_defer_mutex);
if (was_empty)
mutex_lock_defer(&defer_thread_mutex);
mutex_lock_defer(&rcu_defer_mutex);
- cds_list_del(&defer_queue.list);
+ cds_list_del(&URCU_TLS(defer_queue).list);
_rcu_defer_barrier_thread();
- free(defer_queue.q);
- defer_queue.q = NULL;
+ free(URCU_TLS(defer_queue).q);
+ URCU_TLS(defer_queue).q = NULL;
is_empty = cds_list_empty(®istry_defer);
mutex_unlock(&rcu_defer_mutex);
projects / urcu.git / blobdiff