fi
APACHE_SUBST(MOD_MPM_EVENT_LDADD)
-APACHE_MPM_MODULE(event, $enable_mpm_event, event.lo,[
+APACHE_MPM_MODULE(event, $enable_mpm_event, event.lo fdqueue.lo,[
AC_CHECK_FUNCS(pthread_kill)
], , [\$(MOD_MPM_EVENT_LDADD)])
#include "mpm_common.h"
#include "ap_listen.h"
#include "scoreboard.h"
-#include "mpm_unix.h"
+#include "fdqueue.h"
#include "mpm_default.h"
#include "http_vhost.h"
#include "unixd.h"
*/
static apr_pollset_t *event_pollset;
-typedef struct event_conn_state_t event_conn_state_t;
-
/*
* The chain of connections to be shutdown by a worker thread (deferred),
* linked list updated atomically.
apr_atomic_read32(&lingering_count),
apr_atomic_read32(&clogged_count),
apr_atomic_read32(&suspended_count),
- ap_queue_info_num_idlers(worker_queue_info));
+ ap_queue_info_get_idlers(worker_queue_info));
for (i = 0; i < num_listensocks; i++)
apr_pollset_add(event_pollset, &listener_pollfd[i]);
/*
static APR_INLINE int connections_above_limit(void)
{
- apr_uint32_t i_count = ap_queue_info_num_idlers(worker_queue_info);
+ apr_uint32_t i_count = ap_queue_info_get_idlers(worker_queue_info);
if (i_count > 0) {
apr_uint32_t c_count = apr_atomic_read32(&connection_count);
apr_uint32_t l_count = apr_atomic_read32(&lingering_count);
apr_atomic_read32(&connection_count));
ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
"Idle workers: %u",
- ap_queue_info_num_idlers(worker_queue_info));
+ ap_queue_info_get_idlers(worker_queue_info));
workers_were_busy = 1;
}
else if (!listener_may_exit) {
break;
}
- rv = ap_queue_pop_something(worker_queue, &csd, (void **)&cs,
- &ptrans, &te);
+ rv = ap_queue_pop_something(worker_queue, &csd, &cs, &ptrans, &te);
if (rv != APR_SUCCESS) {
/* We get APR_EOF during a graceful shutdown once all the
--- /dev/null
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "fdqueue.h"
+#include "apr_atomic.h"
+
+static const apr_uint32_t zero_pt = APR_UINT32_MAX/2;
+
+struct recycled_pool
+{
+ apr_pool_t *pool;
+ struct recycled_pool *next;
+};
+
+struct fd_queue_info_t
+{
+ apr_uint32_t volatile idlers; /**
+ * >= zero_pt: number of idle worker threads
+ * < zero_pt: number of threads blocked,
+ * waiting for an idle worker
+ */
+ apr_thread_mutex_t *idlers_mutex;
+ apr_thread_cond_t *wait_for_idler;
+ int terminated;
+ int max_idlers;
+ int max_recycled_pools;
+ apr_uint32_t recycled_pools_count;
+ struct recycled_pool *volatile recycled_pools;
+};
+
+static apr_status_t queue_info_cleanup(void *data_)
+{
+ fd_queue_info_t *qi = data_;
+ apr_thread_cond_destroy(qi->wait_for_idler);
+ apr_thread_mutex_destroy(qi->idlers_mutex);
+
+ /* Clean up any pools in the recycled list */
+ for (;;) {
+ struct recycled_pool *first_pool = qi->recycled_pools;
+ if (first_pool == NULL) {
+ break;
+ }
+ if (apr_atomic_casptr
+ ((void*) &(qi->recycled_pools), first_pool->next,
+ first_pool) == first_pool) {
+ apr_pool_destroy(first_pool->pool);
+ }
+ }
+
+ return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_info_create(fd_queue_info_t ** queue_info,
+ apr_pool_t * pool, int max_idlers,
+ int max_recycled_pools)
+{
+ apr_status_t rv;
+ fd_queue_info_t *qi;
+
+ qi = apr_pcalloc(pool, sizeof(*qi));
+
+ rv = apr_thread_mutex_create(&qi->idlers_mutex, APR_THREAD_MUTEX_DEFAULT,
+ pool);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ rv = apr_thread_cond_create(&qi->wait_for_idler, pool);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ qi->recycled_pools = NULL;
+ qi->max_recycled_pools = max_recycled_pools;
+ qi->max_idlers = max_idlers;
+ qi->idlers = zero_pt;
+ apr_pool_cleanup_register(pool, qi, queue_info_cleanup,
+ apr_pool_cleanup_null);
+
+ *queue_info = qi;
+
+ return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_info_set_idle(fd_queue_info_t * queue_info,
+ apr_pool_t * pool_to_recycle)
+{
+ apr_status_t rv;
+
+ ap_push_pool(queue_info, pool_to_recycle);
+
+ /* If other threads are waiting on a worker, wake one up */
+ if (apr_atomic_inc32(&queue_info->idlers) < zero_pt) {
+ rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ AP_DEBUG_ASSERT(0);
+ return rv;
+ }
+ rv = apr_thread_cond_signal(queue_info->wait_for_idler);
+ if (rv != APR_SUCCESS) {
+ apr_thread_mutex_unlock(queue_info->idlers_mutex);
+ return rv;
+ }
+ rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ }
+
+ return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_info_try_get_idler(fd_queue_info_t * queue_info)
+{
+ /* Don't block if there isn't any idle worker. */
+ for (;;) {
+ apr_uint32_t idlers = queue_info->idlers;
+ if (idlers <= zero_pt) {
+ return APR_EAGAIN;
+ }
+ if (apr_atomic_cas32(&queue_info->idlers, idlers - 1,
+ idlers) == idlers) {
+ return APR_SUCCESS;
+ }
+ }
+}
+
+apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t * queue_info,
+ int *had_to_block)
+{
+ apr_status_t rv;
+
+ /* Block if there isn't any idle worker.
+ * apr_atomic_add32(x, -1) does the same as dec32(x), except
+ * that it returns the previous value (unlike dec32's bool).
+ */
+ if (apr_atomic_add32(&queue_info->idlers, -1) <= zero_pt) {
+ rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ AP_DEBUG_ASSERT(0);
+ apr_atomic_inc32(&(queue_info->idlers)); /* back out dec */
+ return rv;
+ }
+ /* Re-check the idle worker count to guard against a
+ * race condition. Now that we're in the mutex-protected
+ * region, one of two things may have happened:
+ * - If the idle worker count is still negative, the
+ * workers are all still busy, so it's safe to
+ * block on a condition variable.
+ * - If the idle worker count is non-negative, then a
+ * worker has become idle since the first check
+ * of queue_info->idlers above. It's possible
+ * that the worker has also signaled the condition
+ * variable--and if so, the listener missed it
+ * because it wasn't yet blocked on the condition
+ * variable. But if the idle worker count is
+ * now non-negative, it's safe for this function to
+ * return immediately.
+ *
+ * A "negative value" (relative to zero_pt) in
+ * queue_info->idlers tells how many
+ * threads are waiting on an idle worker.
+ */
+ if (queue_info->idlers < zero_pt) {
+ *had_to_block = 1;
+ rv = apr_thread_cond_wait(queue_info->wait_for_idler,
+ queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ apr_status_t rv2;
+ AP_DEBUG_ASSERT(0);
+ rv2 = apr_thread_mutex_unlock(queue_info->idlers_mutex);
+ if (rv2 != APR_SUCCESS) {
+ return rv2;
+ }
+ return rv;
+ }
+ }
+ rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ }
+
+ if (queue_info->terminated) {
+ return APR_EOF;
+ }
+ else {
+ return APR_SUCCESS;
+ }
+}
+
+apr_uint32_t ap_queue_info_get_idlers(fd_queue_info_t * queue_info)
+{
+ apr_uint32_t val;
+ val = apr_atomic_read32(&queue_info->idlers);
+ if (val <= zero_pt)
+ return 0;
+ return val - zero_pt;
+}
+
+void ap_push_pool(fd_queue_info_t * queue_info,
+ apr_pool_t * pool_to_recycle)
+{
+ struct recycled_pool *new_recycle;
+ /* If we have been given a pool to recycle, atomically link
+ * it into the queue_info's list of recycled pools
+ */
+ if (!pool_to_recycle)
+ return;
+
+ if (queue_info->max_recycled_pools >= 0) {
+ apr_uint32_t cnt = apr_atomic_read32(&queue_info->recycled_pools_count);
+ if (cnt >= queue_info->max_recycled_pools) {
+ apr_pool_destroy(pool_to_recycle);
+ return;
+ }
+ apr_atomic_inc32(&queue_info->recycled_pools_count);
+ }
+
+ apr_pool_clear(pool_to_recycle);
+ new_recycle = (struct recycled_pool *) apr_palloc(pool_to_recycle,
+ sizeof (*new_recycle));
+ new_recycle->pool = pool_to_recycle;
+ for (;;) {
+ /*
+ * Save queue_info->recycled_pool in local variable next because
+ * new_recycle->next can be changed after apr_atomic_casptr
+ * function call. For gory details see PR 44402.
+ */
+ struct recycled_pool *next = queue_info->recycled_pools;
+ new_recycle->next = next;
+ if (apr_atomic_casptr((void*) &(queue_info->recycled_pools),
+ new_recycle, next) == next)
+ break;
+ }
+}
+
+void ap_pop_pool(apr_pool_t ** recycled_pool, fd_queue_info_t * queue_info)
+{
+ /* Atomically pop a pool from the recycled list */
+
+ /* This function is safe only as long as it is single threaded because
+ * it reaches into the queue and accesses "next" which can change.
+ * We are OK today because it is only called from the listener thread.
+ * cas-based pushes do not have the same limitation - any number can
+ * happen concurrently with a single cas-based pop.
+ */
+
+ *recycled_pool = NULL;
+
+
+ /* Atomically pop a pool from the recycled list */
+ for (;;) {
+ struct recycled_pool *first_pool = queue_info->recycled_pools;
+ if (first_pool == NULL) {
+ break;
+ }
+ if (apr_atomic_casptr
+ ((void*) &(queue_info->recycled_pools),
+ first_pool->next, first_pool) == first_pool) {
+ *recycled_pool = first_pool->pool;
+ if (queue_info->max_recycled_pools >= 0)
+ apr_atomic_dec32(&queue_info->recycled_pools_count);
+ break;
+ }
+ }
+}
+
+void ap_free_idle_pools(fd_queue_info_t *queue_info)
+{
+ apr_pool_t *p;
+
+ queue_info->max_recycled_pools = 0;
+ do {
+ ap_pop_pool(&p, queue_info);
+ if (p != NULL)
+ apr_pool_destroy(p);
+ } while (p != NULL);
+}
+
+
+apr_status_t ap_queue_info_term(fd_queue_info_t * queue_info)
+{
+ apr_status_t rv;
+ rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ queue_info->terminated = 1;
+ apr_thread_cond_broadcast(queue_info->wait_for_idler);
+ return apr_thread_mutex_unlock(queue_info->idlers_mutex);
+}
+
+/**
+ * Detects when the fd_queue_t is full. This utility function is expected
+ * to be called from within critical sections, and is not threadsafe.
+ */
+#define ap_queue_full(queue) ((queue)->nelts == (queue)->bounds)
+
+/**
+ * Detects when the fd_queue_t is empty. This utility function is expected
+ * to be called from within critical sections, and is not threadsafe.
+ */
+#define ap_queue_empty(queue) ((queue)->nelts == 0 && APR_RING_EMPTY(&queue->timers ,timer_event_t, link))
+
+/**
+ * Callback routine that is called to destroy this
+ * fd_queue_t when its pool is destroyed.
+ */
+static apr_status_t ap_queue_destroy(void *data)
+{
+ fd_queue_t *queue = data;
+
+ /* Ignore errors here, we can't do anything about them anyway.
+ * XXX: We should at least try to signal an error here, it is
+ * indicative of a programmer error. -aaron */
+ apr_thread_cond_destroy(queue->not_empty);
+ apr_thread_mutex_destroy(queue->one_big_mutex);
+
+ return APR_SUCCESS;
+}
+
+/**
+ * Initialize the fd_queue_t.
+ */
+apr_status_t ap_queue_init(fd_queue_t * queue, int queue_capacity,
+ apr_pool_t * a)
+{
+ int i;
+ apr_status_t rv;
+
+ if ((rv = apr_thread_mutex_create(&queue->one_big_mutex,
+ APR_THREAD_MUTEX_DEFAULT,
+ a)) != APR_SUCCESS) {
+ return rv;
+ }
+ if ((rv = apr_thread_cond_create(&queue->not_empty, a)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ APR_RING_INIT(&queue->timers, timer_event_t, link);
+
+ queue->data = apr_palloc(a, queue_capacity * sizeof(fd_queue_elem_t));
+ queue->bounds = queue_capacity;
+ queue->nelts = 0;
+ queue->in = 0;
+ queue->out = 0;
+
+ /* Set all the sockets in the queue to NULL */
+ for (i = 0; i < queue_capacity; ++i)
+ queue->data[i].sd = NULL;
+
+ apr_pool_cleanup_register(a, queue, ap_queue_destroy,
+ apr_pool_cleanup_null);
+
+ return APR_SUCCESS;
+}
+
+/**
+ * Push a new socket onto the queue.
+ *
+ * precondition: ap_queue_info_wait_for_idler has already been called
+ * to reserve an idle worker thread
+ */
+apr_status_t ap_queue_push(fd_queue_t * queue, apr_socket_t * sd,
+ event_conn_state_t * ecs, apr_pool_t * p)
+{
+ fd_queue_elem_t *elem;
+ apr_status_t rv;
+
+ if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ AP_DEBUG_ASSERT(!queue->terminated);
+ AP_DEBUG_ASSERT(!ap_queue_full(queue));
+
+ elem = &queue->data[queue->in];
+ queue->in++;
+ if (queue->in >= queue->bounds)
+ queue->in -= queue->bounds;
+ elem->sd = sd;
+ elem->ecs = ecs;
+ elem->p = p;
+ queue->nelts++;
+
+ apr_thread_cond_signal(queue->not_empty);
+
+ if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_push_timer(fd_queue_t * queue, timer_event_t *te)
+{
+ apr_status_t rv;
+
+ if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ AP_DEBUG_ASSERT(!queue->terminated);
+
+ APR_RING_INSERT_TAIL(&queue->timers, te, timer_event_t, link);
+
+ apr_thread_cond_signal(queue->not_empty);
+
+ if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ return APR_SUCCESS;
+}
+
+/**
+ * Retrieves the next available socket from the queue. If there are no
+ * sockets available, it will block until one becomes available.
+ * Once retrieved, the socket is placed into the address specified by
+ * 'sd'.
+ */
+apr_status_t ap_queue_pop_something(fd_queue_t * queue, apr_socket_t ** sd,
+ event_conn_state_t ** ecs, apr_pool_t ** p,
+ timer_event_t ** te_out)
+{
+ fd_queue_elem_t *elem;
+ apr_status_t rv;
+
+ if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ /* Keep waiting until we wake up and find that the queue is not empty. */
+ if (ap_queue_empty(queue)) {
+ if (!queue->terminated) {
+ apr_thread_cond_wait(queue->not_empty, queue->one_big_mutex);
+ }
+ /* If we wake up and it's still empty, then we were interrupted */
+ if (ap_queue_empty(queue)) {
+ rv = apr_thread_mutex_unlock(queue->one_big_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ if (queue->terminated) {
+ return APR_EOF; /* no more elements ever again */
+ }
+ else {
+ return APR_EINTR;
+ }
+ }
+ }
+
+ *te_out = NULL;
+
+ if (!APR_RING_EMPTY(&queue->timers, timer_event_t, link)) {
+ *te_out = APR_RING_FIRST(&queue->timers);
+ APR_RING_REMOVE(*te_out, link);
+ }
+ else {
+ elem = &queue->data[queue->out];
+ queue->out++;
+ if (queue->out >= queue->bounds)
+ queue->out -= queue->bounds;
+ queue->nelts--;
+ *sd = elem->sd;
+ *ecs = elem->ecs;
+ *p = elem->p;
+#ifdef AP_DEBUG
+ elem->sd = NULL;
+ elem->p = NULL;
+#endif /* AP_DEBUG */
+ }
+
+ rv = apr_thread_mutex_unlock(queue->one_big_mutex);
+ return rv;
+}
+
+static apr_status_t queue_interrupt(fd_queue_t *queue, int all, int term)
+{
+ apr_status_t rv;
+
+ if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+ /* we must hold one_big_mutex when setting this... otherwise,
+ * we could end up setting it and waking everybody up just after a
+ * would-be popper checks it but right before they block
+ */
+ if (term) {
+ queue->terminated = 1;
+ }
+ if (all)
+ apr_thread_cond_broadcast(queue->not_empty);
+ else
+ apr_thread_cond_signal(queue->not_empty);
+ return apr_thread_mutex_unlock(queue->one_big_mutex);
+}
+
+apr_status_t ap_queue_interrupt_all(fd_queue_t * queue)
+{
+ return queue_interrupt(queue, 1, 0);
+}
+
+apr_status_t ap_queue_interrupt_one(fd_queue_t * queue)
+{
+ return queue_interrupt(queue, 0, 0);
+}
+
+apr_status_t ap_queue_term(fd_queue_t * queue)
+{
+ return queue_interrupt(queue, 1, 1);
+}
*/
/**
- * @file mpm_unix.h
+ * @file event/fdqueue.h
* @brief fd queue declarations
*
- * @defgroup APACHE_MPM Multi-Processing Modules
- * @ingroup APACHE
+ * @addtogroup APACHE_MPM_EVENT
* @{
*/
-#ifndef MPM_UNIX_H
-#define MPM_UNIX_H
-
-#ifndef WIN32
-
-#include <apr.h>
-#include <apr_ring.h>
-#include <apr_pools.h>
-#include <apr_network_io.h>
+#ifndef FDQUEUE_H
+#define FDQUEUE_H
+#include "httpd.h"
+#include <stdlib.h>
+#if APR_HAVE_UNISTD_H
+#include <unistd.h>
+#endif
#include <apr_thread_mutex.h>
#include <apr_thread_cond.h>
+#include <sys/types.h>
+#if APR_HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#include <apr_errno.h>
#include "ap_mpm.h"
-struct fd_queue_info_t; /* opaque */
-struct fd_queue_elem_t; /* opaque */
typedef struct fd_queue_info_t fd_queue_info_t;
-typedef struct fd_queue_elem_t fd_queue_elem_t;
+typedef struct event_conn_state_t event_conn_state_t;
-apr_status_t ap_queue_info_create(fd_queue_info_t **queue_info,
- apr_pool_t *pool, int max_idlers,
+apr_status_t ap_queue_info_create(fd_queue_info_t ** queue_info,
+ apr_pool_t * pool, int max_idlers,
int max_recycled_pools);
-apr_status_t ap_queue_info_set_idle(fd_queue_info_t *queue_info,
- apr_pool_t *pool_to_recycle);
-apr_status_t ap_queue_info_try_get_idler(fd_queue_info_t *queue_info);
-apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t *queue_info,
+apr_status_t ap_queue_info_set_idle(fd_queue_info_t * queue_info,
+ apr_pool_t * pool_to_recycle);
+apr_status_t ap_queue_info_try_get_idler(fd_queue_info_t * queue_info);
+apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t * queue_info,
int *had_to_block);
-apr_uint32_t ap_queue_info_num_idlers(fd_queue_info_t *queue_info);
-apr_status_t ap_queue_info_term(fd_queue_info_t *queue_info);
+apr_status_t ap_queue_info_term(fd_queue_info_t * queue_info);
+apr_uint32_t ap_queue_info_get_idlers(fd_queue_info_t * queue_info);
+void ap_free_idle_pools(fd_queue_info_t *queue_info);
+
+struct fd_queue_elem_t
+{
+ apr_socket_t *sd;
+ apr_pool_t *p;
+ event_conn_state_t *ecs;
+};
+typedef struct fd_queue_elem_t fd_queue_elem_t;
typedef struct timer_event_t timer_event_t;
};
typedef struct fd_queue_t fd_queue_t;
-void ap_pop_pool(apr_pool_t **recycled_pool, fd_queue_info_t *queue_info);
-void ap_push_pool(fd_queue_info_t *queue_info, apr_pool_t *pool_to_recycle);
-void ap_free_idle_pools(fd_queue_info_t *queue_info);
+void ap_pop_pool(apr_pool_t ** recycled_pool, fd_queue_info_t * queue_info);
+void ap_push_pool(fd_queue_info_t * queue_info,
+ apr_pool_t * pool_to_recycle);
-apr_status_t ap_queue_init(fd_queue_t *queue, int queue_capacity,
- apr_pool_t *a);
-apr_status_t ap_queue_push(fd_queue_t *queue, apr_socket_t *sd,
- void *baton, apr_pool_t *p);
+apr_status_t ap_queue_init(fd_queue_t * queue, int queue_capacity,
+ apr_pool_t * a);
+apr_status_t ap_queue_push(fd_queue_t * queue, apr_socket_t * sd,
+ event_conn_state_t * ecs, apr_pool_t * p);
apr_status_t ap_queue_push_timer(fd_queue_t *queue, timer_event_t *te);
-apr_status_t ap_queue_pop_something(fd_queue_t *queue, apr_socket_t **sd,
- void **baton, apr_pool_t **p,
- timer_event_t **te);
-#define ap_queue_pop(q_, s_, p_) \
- ap_queue_pop_something((q_), (s_), NULL, (p_), NULL)
-apr_status_t ap_queue_interrupt_all(fd_queue_t *queue);
-apr_status_t ap_queue_interrupt_one(fd_queue_t *queue);
-apr_status_t ap_queue_term(fd_queue_t *queue);
-
-#endif /* WIN32 */
+apr_status_t ap_queue_pop_something(fd_queue_t * queue, apr_socket_t ** sd,
+ event_conn_state_t ** ecs, apr_pool_t ** p,
+ timer_event_t ** te);
+apr_status_t ap_queue_interrupt_all(fd_queue_t * queue);
+apr_status_t ap_queue_interrupt_one(fd_queue_t * queue);
+apr_status_t ap_queue_term(fd_queue_t * queue);
-#endif /* MPM_UNIX_H */
+#endif /* FDQUEUE_H */
/** @} */
APACHE_MPMPATH_INIT(worker)
dnl ## XXX - Need a more thorough check of the proper flags to use
-APACHE_MPM_MODULE(worker, $enable_mpm_worker, worker.lo,[
+APACHE_MPM_MODULE(worker, $enable_mpm_worker, worker.lo fdqueue.lo,[
AC_CHECK_FUNCS(pthread_kill)
])
--- /dev/null
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "fdqueue.h"
+#include "apr_atomic.h"
+
+typedef struct recycled_pool {
+ apr_pool_t *pool;
+ struct recycled_pool *next;
+} recycled_pool;
+
+struct fd_queue_info_t {
+ volatile apr_uint32_t idlers;
+ apr_thread_mutex_t *idlers_mutex;
+ apr_thread_cond_t *wait_for_idler;
+ int terminated;
+ int max_idlers;
+ recycled_pool *recycled_pools;
+};
+
+static apr_status_t queue_info_cleanup(void *data_)
+{
+ fd_queue_info_t *qi = data_;
+ apr_thread_cond_destroy(qi->wait_for_idler);
+ apr_thread_mutex_destroy(qi->idlers_mutex);
+
+ /* Clean up any pools in the recycled list */
+ for (;;) {
+ struct recycled_pool *first_pool = qi->recycled_pools;
+ if (first_pool == NULL) {
+ break;
+ }
+ if (apr_atomic_casptr((void*)&(qi->recycled_pools), first_pool->next,
+ first_pool) == first_pool) {
+ apr_pool_destroy(first_pool->pool);
+ }
+ }
+
+ return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_info_create(fd_queue_info_t **queue_info,
+ apr_pool_t *pool, int max_idlers)
+{
+ apr_status_t rv;
+ fd_queue_info_t *qi;
+
+ qi = apr_pcalloc(pool, sizeof(*qi));
+
+ rv = apr_thread_mutex_create(&qi->idlers_mutex, APR_THREAD_MUTEX_DEFAULT,
+ pool);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ rv = apr_thread_cond_create(&qi->wait_for_idler, pool);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ qi->recycled_pools = NULL;
+ qi->max_idlers = max_idlers;
+ apr_pool_cleanup_register(pool, qi, queue_info_cleanup,
+ apr_pool_cleanup_null);
+
+ *queue_info = qi;
+
+ return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_info_set_idle(fd_queue_info_t *queue_info,
+ apr_pool_t *pool_to_recycle)
+{
+ apr_status_t rv;
+
+ /* If we have been given a pool to recycle, atomically link
+ * it into the queue_info's list of recycled pools
+ */
+ if (pool_to_recycle) {
+ struct recycled_pool *new_recycle;
+ new_recycle = (struct recycled_pool *)apr_palloc(pool_to_recycle,
+ sizeof(*new_recycle));
+ new_recycle->pool = pool_to_recycle;
+ for (;;) {
+ /* Save queue_info->recycled_pool in local variable next because
+ * new_recycle->next can be changed after apr_atomic_casptr
+ * function call. For gory details see PR 44402.
+ */
+ struct recycled_pool *next = queue_info->recycled_pools;
+ new_recycle->next = next;
+ if (apr_atomic_casptr((void*)&(queue_info->recycled_pools),
+ new_recycle, next) == next) {
+ break;
+ }
+ }
+ }
+
+ /* If this thread makes the idle worker count nonzero,
+ * wake up the listener. */
+ if (apr_atomic_inc32(&queue_info->idlers) == 0) {
+ rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ rv = apr_thread_cond_signal(queue_info->wait_for_idler);
+ if (rv != APR_SUCCESS) {
+ apr_thread_mutex_unlock(queue_info->idlers_mutex);
+ return rv;
+ }
+ rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ }
+
+ return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t *queue_info,
+ apr_pool_t **recycled_pool)
+{
+ apr_status_t rv;
+
+ *recycled_pool = NULL;
+
+ /* Block if the count of idle workers is zero */
+ if (queue_info->idlers == 0) {
+ rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ /* Re-check the idle worker count to guard against a
+ * race condition. Now that we're in the mutex-protected
+ * region, one of two things may have happened:
+ * - If the idle worker count is still zero, the
+ * workers are all still busy, so it's safe to
+ * block on a condition variable, BUT
+ * we need to check for idle worker count again
+ * when we are signaled since it can happen that
+ * we are signaled by a worker thread that went idle
+ * but received a context switch before it could
+ * tell us. If it does signal us later once it is on
+ * CPU again there might be no idle worker left.
+ * See
+ * https://issues.apache.org/bugzilla/show_bug.cgi?id=45605#c4
+ * - If the idle worker count is nonzero, then a
+ * worker has become idle since the first check
+ * of queue_info->idlers above. It's possible
+ * that the worker has also signaled the condition
+ * variable--and if so, the listener missed it
+ * because it wasn't yet blocked on the condition
+ * variable. But if the idle worker count is
+ * now nonzero, it's safe for this function to
+ * return immediately.
+ */
+ while (queue_info->idlers == 0) {
+ rv = apr_thread_cond_wait(queue_info->wait_for_idler,
+ queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ apr_status_t rv2;
+ rv2 = apr_thread_mutex_unlock(queue_info->idlers_mutex);
+ if (rv2 != APR_SUCCESS) {
+ return rv2;
+ }
+ return rv;
+ }
+ }
+ rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ }
+
+ /* Atomically decrement the idle worker count */
+ apr_atomic_dec32(&(queue_info->idlers));
+
+ /* Atomically pop a pool from the recycled list */
+
+ /* This function is safe only as long as it is single threaded because
+ * it reaches into the queue and accesses "next" which can change.
+ * We are OK today because it is only called from the listener thread.
+ * cas-based pushes do not have the same limitation - any number can
+ * happen concurrently with a single cas-based pop.
+ */
+
+ for (;;) {
+ struct recycled_pool *first_pool = queue_info->recycled_pools;
+ if (first_pool == NULL) {
+ break;
+ }
+ if (apr_atomic_casptr((void*)&(queue_info->recycled_pools), first_pool->next,
+ first_pool) == first_pool) {
+ *recycled_pool = first_pool->pool;
+ break;
+ }
+ }
+
+ if (queue_info->terminated) {
+ return APR_EOF;
+ }
+ else {
+ return APR_SUCCESS;
+ }
+}
+
+apr_status_t ap_queue_info_term(fd_queue_info_t *queue_info)
+{
+ apr_status_t rv;
+ rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ queue_info->terminated = 1;
+ apr_thread_cond_broadcast(queue_info->wait_for_idler);
+ return apr_thread_mutex_unlock(queue_info->idlers_mutex);
+}
+
+/**
+ * Detects when the fd_queue_t is full. This utility function is expected
+ * to be called from within critical sections, and is not threadsafe.
+ */
+#define ap_queue_full(queue) ((queue)->nelts == (queue)->bounds)
+
+/**
+ * Detects when the fd_queue_t is empty. This utility function is expected
+ * to be called from within critical sections, and is not threadsafe.
+ */
+#define ap_queue_empty(queue) ((queue)->nelts == 0)
+
+/**
+ * Callback routine that is called to destroy this
+ * fd_queue_t when its pool is destroyed.
+ */
+static apr_status_t ap_queue_destroy(void *data)
+{
+ fd_queue_t *queue = data;
+
+ /* Ignore errors here, we can't do anything about them anyway.
+ * XXX: We should at least try to signal an error here, it is
+ * indicative of a programmer error. -aaron */
+ apr_thread_cond_destroy(queue->not_empty);
+ apr_thread_mutex_destroy(queue->one_big_mutex);
+
+ return APR_SUCCESS;
+}
+
+/**
+ * Initialize the fd_queue_t.
+ */
+apr_status_t ap_queue_init(fd_queue_t *queue, int queue_capacity, apr_pool_t *a)
+{
+ int i;
+ apr_status_t rv;
+
+ if ((rv = apr_thread_mutex_create(&queue->one_big_mutex,
+ APR_THREAD_MUTEX_DEFAULT, a)) != APR_SUCCESS) {
+ return rv;
+ }
+ if ((rv = apr_thread_cond_create(&queue->not_empty, a)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ queue->data = apr_palloc(a, queue_capacity * sizeof(fd_queue_elem_t));
+ queue->bounds = queue_capacity;
+ queue->nelts = 0;
+ queue->in = 0;
+ queue->out = 0;
+
+ /* Set all the sockets in the queue to NULL */
+ for (i = 0; i < queue_capacity; ++i)
+ queue->data[i].sd = NULL;
+
+ apr_pool_cleanup_register(a, queue, ap_queue_destroy, apr_pool_cleanup_null);
+
+ return APR_SUCCESS;
+}
+
+/**
+ * Push a new socket onto the queue.
+ *
+ * precondition: ap_queue_info_wait_for_idler has already been called
+ * to reserve an idle worker thread
+ */
+apr_status_t ap_queue_push(fd_queue_t *queue, apr_socket_t *sd, apr_pool_t *p)
+{
+ fd_queue_elem_t *elem;
+ apr_status_t rv;
+
+ if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ AP_DEBUG_ASSERT(!queue->terminated);
+ AP_DEBUG_ASSERT(!ap_queue_full(queue));
+
+ elem = &queue->data[queue->in];
+ queue->in++;
+ if (queue->in >= queue->bounds)
+ queue->in -= queue->bounds;
+ elem->sd = sd;
+ elem->p = p;
+ queue->nelts++;
+
+ apr_thread_cond_signal(queue->not_empty);
+
+ if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ return APR_SUCCESS;
+}
+
+/**
+ * Retrieves the next available socket from the queue. If there are no
+ * sockets available, it will block until one becomes available.
+ * Once retrieved, the socket is placed into the address specified by
+ * 'sd'.
+ */
+apr_status_t ap_queue_pop(fd_queue_t *queue, apr_socket_t **sd, apr_pool_t **p)
+{
+ fd_queue_elem_t *elem;
+ apr_status_t rv;
+
+ if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+
+ /* Keep waiting until we wake up and find that the queue is not empty. */
+ if (ap_queue_empty(queue)) {
+ if (!queue->terminated) {
+ apr_thread_cond_wait(queue->not_empty, queue->one_big_mutex);
+ }
+ /* If we wake up and it's still empty, then we were interrupted */
+ if (ap_queue_empty(queue)) {
+ rv = apr_thread_mutex_unlock(queue->one_big_mutex);
+ if (rv != APR_SUCCESS) {
+ return rv;
+ }
+ if (queue->terminated) {
+ return APR_EOF; /* no more elements ever again */
+ }
+ else {
+ return APR_EINTR;
+ }
+ }
+ }
+
+ elem = &queue->data[queue->out];
+ queue->out++;
+ if (queue->out >= queue->bounds)
+ queue->out -= queue->bounds;
+ queue->nelts--;
+ *sd = elem->sd;
+ *p = elem->p;
+#ifdef AP_DEBUG
+ elem->sd = NULL;
+ elem->p = NULL;
+#endif /* AP_DEBUG */
+
+ rv = apr_thread_mutex_unlock(queue->one_big_mutex);
+ return rv;
+}
+
+static apr_status_t queue_interrupt_all(fd_queue_t *queue, int term)
+{
+ apr_status_t rv;
+
+ if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+ return rv;
+ }
+ /* we must hold one_big_mutex when setting this... otherwise,
+ * we could end up setting it and waking everybody up just after a
+ * would-be popper checks it but right before they block
+ */
+ if (term) {
+ queue->terminated = 1;
+ }
+ apr_thread_cond_broadcast(queue->not_empty);
+ return apr_thread_mutex_unlock(queue->one_big_mutex);
+}
+
+apr_status_t ap_queue_interrupt_all(fd_queue_t *queue)
+{
+ return queue_interrupt_all(queue, 0);
+}
+
+apr_status_t ap_queue_term(fd_queue_t *queue)
+{
+ return queue_interrupt_all(queue, 1);
+}
--- /dev/null
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @file worker/fdqueue.h
+ * @brief fd queue declarations
+ *
+ * @addtogroup APACHE_MPM_WORKER
+ * @{
+ */
+
+#ifndef FDQUEUE_H
+#define FDQUEUE_H
+#include "httpd.h"
+#include <stdlib.h>
+#if APR_HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <apr_thread_mutex.h>
+#include <apr_thread_cond.h>
+#include <sys/types.h>
+#if APR_HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#include <apr_errno.h>
+
+typedef struct fd_queue_info_t fd_queue_info_t;
+
+apr_status_t ap_queue_info_create(fd_queue_info_t **queue_info,
+ apr_pool_t *pool, int max_idlers);
+apr_status_t ap_queue_info_set_idle(fd_queue_info_t *queue_info,
+ apr_pool_t *pool_to_recycle);
+apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t *queue_info,
+ apr_pool_t **recycled_pool);
+apr_status_t ap_queue_info_term(fd_queue_info_t *queue_info);
+
+struct fd_queue_elem_t {
+ apr_socket_t *sd;
+ apr_pool_t *p;
+};
+typedef struct fd_queue_elem_t fd_queue_elem_t;
+
+struct fd_queue_t {
+ fd_queue_elem_t *data;
+ unsigned int nelts;
+ unsigned int bounds;
+ unsigned int in;
+ unsigned int out;
+ apr_thread_mutex_t *one_big_mutex;
+ apr_thread_cond_t *not_empty;
+ int terminated;
+};
+typedef struct fd_queue_t fd_queue_t;
+
+apr_status_t ap_queue_init(fd_queue_t *queue, int queue_capacity, apr_pool_t *a);
+apr_status_t ap_queue_push(fd_queue_t *queue, apr_socket_t *sd, apr_pool_t *p);
+apr_status_t ap_queue_pop(fd_queue_t *queue, apr_socket_t **sd, apr_pool_t **p);
+apr_status_t ap_queue_interrupt_all(fd_queue_t *queue);
+apr_status_t ap_queue_term(fd_queue_t *queue);
+
+#endif /* FDQUEUE_H */
+/** @} */
#include "mpm_common.h"
#include "ap_listen.h"
#include "scoreboard.h"
-#include "mpm_unix.h"
+#include "fdqueue.h"
#include "mpm_default.h"
#include "util_mutex.h"
#include "unixd.h"
if (listener_may_exit) break;
if (!have_idle_worker) {
- rv = ap_queue_info_wait_for_idler(worker_queue_info, NULL);
+ /* the following pops a recycled ptrans pool off a stack
+ * if there is one, in addition to reserving a worker thread
+ */
+ rv = ap_queue_info_wait_for_idler(worker_queue_info,
+ &ptrans);
if (APR_STATUS_IS_EOF(rv)) {
break; /* we've been signaled to die now */
}
} /* if/else */
if (!listener_may_exit) {
- /* the following pops a recycled ptrans pool off a stack */
- ap_pop_pool(&ptrans, worker_queue_info);
if (ptrans == NULL) {
/* we can't use a recycled transaction pool this time.
* create a new transaction pool */
apr_allocator_max_free_set(allocator, ap_max_mem_free);
apr_pool_create_ex(&ptrans, pconf, NULL, allocator);
apr_allocator_owner_set(allocator, ptrans);
- apr_pool_tag(ptrans, "transaction");
}
+ apr_pool_tag(ptrans, "transaction");
rv = lr->accept_func(&csd, lr, ptrans);
/* later we trash rv and rely on csd to indicate success/failure */
AP_DEBUG_ASSERT(rv == APR_SUCCESS || !csd);
accept_mutex_error("unlock", rv, process_slot);
}
if (csd != NULL) {
- rv = ap_queue_push(worker_queue, csd, NULL, ptrans);
+ rv = ap_queue_push(worker_queue, csd, ptrans);
if (rv) {
/* trash the connection; we couldn't queue the connected
* socket to a worker
}
rv = ap_queue_info_create(&worker_queue_info, pchild,
- threads_per_child, -1);
+ threads_per_child);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03141)
"ap_queue_info_create() failed");
#ifndef WIN32
-#include "mpm_unix.h"
-
+#include "apr.h"
#include "apr_thread_proc.h"
#include "apr_signal.h"
#include "apr_strings.h"
#include "apr_getopt.h"
#include "apr_optional.h"
#include "apr_allocator.h"
-#include "apr_atomic.h"
-#include "apr_errno.h"
#include "httpd.h"
#include "http_config.h"
#include "http_log.h"
#include "http_main.h"
#include "mpm_common.h"
+#include "ap_mpm.h"
#include "ap_listen.h"
#include "scoreboard.h"
#include "util_mutex.h"
return APR_SUCCESS;
}
-
-/*
- * fdqueue code used by MPMs event and worker.
- * Not part of the API, so not AP_DECLARE()d.
- */
-
-static const apr_uint32_t zero_pt = APR_UINT32_MAX/2;
-
-struct recycled_pool
-{
- apr_pool_t *pool;
- struct recycled_pool *next;
-};
-
-struct fd_queue_info_t
-{
- apr_uint32_t volatile idlers; /**
- * >= zero_pt: number of idle worker threads
- * < zero_pt: number of threads blocked,
- * waiting for an idle worker
- */
- apr_thread_mutex_t *idlers_mutex;
- apr_thread_cond_t *wait_for_idler;
- int terminated;
- int max_idlers;
- int max_recycled_pools;
- apr_uint32_t recycled_pools_count;
- struct recycled_pool *volatile recycled_pools;
-};
-
-struct fd_queue_elem_t
-{
- apr_socket_t *sd;
- apr_pool_t *p;
- void *baton;
-};
-
-static apr_status_t queue_info_cleanup(void *data_)
-{
- fd_queue_info_t *qi = data_;
- apr_thread_cond_destroy(qi->wait_for_idler);
- apr_thread_mutex_destroy(qi->idlers_mutex);
-
- /* Clean up any pools in the recycled list */
- for (;;) {
- struct recycled_pool *first_pool = qi->recycled_pools;
- if (first_pool == NULL) {
- break;
- }
- if (apr_atomic_casptr((void *)&qi->recycled_pools, first_pool->next,
- first_pool) == first_pool) {
- apr_pool_destroy(first_pool->pool);
- }
- }
-
- return APR_SUCCESS;
-}
-
-apr_status_t ap_queue_info_create(fd_queue_info_t **queue_info,
- apr_pool_t *pool, int max_idlers,
- int max_recycled_pools)
-{
- apr_status_t rv;
- fd_queue_info_t *qi;
-
- qi = apr_pcalloc(pool, sizeof(*qi));
-
- rv = apr_thread_mutex_create(&qi->idlers_mutex, APR_THREAD_MUTEX_DEFAULT,
- pool);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- rv = apr_thread_cond_create(&qi->wait_for_idler, pool);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- qi->recycled_pools = NULL;
- qi->max_recycled_pools = max_recycled_pools;
- qi->max_idlers = max_idlers;
- qi->idlers = zero_pt;
- apr_pool_cleanup_register(pool, qi, queue_info_cleanup,
- apr_pool_cleanup_null);
-
- *queue_info = qi;
-
- return APR_SUCCESS;
-}
-
-apr_status_t ap_queue_info_set_idle(fd_queue_info_t *queue_info,
- apr_pool_t *pool_to_recycle)
-{
- apr_status_t rv;
-
- ap_push_pool(queue_info, pool_to_recycle);
-
- /* If other threads are waiting on a worker, wake one up */
- if (apr_atomic_inc32(&queue_info->idlers) < zero_pt) {
- rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- AP_DEBUG_ASSERT(0);
- return rv;
- }
- rv = apr_thread_cond_signal(queue_info->wait_for_idler);
- if (rv != APR_SUCCESS) {
- apr_thread_mutex_unlock(queue_info->idlers_mutex);
- return rv;
- }
- rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- }
-
- return APR_SUCCESS;
-}
-
-apr_status_t ap_queue_info_try_get_idler(fd_queue_info_t *queue_info)
-{
- /* Don't block if there isn't any idle worker. */
- for (;;) {
- apr_uint32_t idlers = queue_info->idlers;
- if (idlers <= zero_pt) {
- return APR_EAGAIN;
- }
- if (apr_atomic_cas32(&queue_info->idlers, idlers - 1,
- idlers) == idlers) {
- return APR_SUCCESS;
- }
- }
-}
-
-apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t *queue_info,
- int *had_to_block)
-{
- apr_status_t rv;
-
- /* Block if there isn't any idle worker.
- * apr_atomic_add32(x, -1) does the same as dec32(x), except
- * that it returns the previous value (unlike dec32's bool).
- */
- if (apr_atomic_add32(&queue_info->idlers, -1) <= zero_pt) {
- rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- AP_DEBUG_ASSERT(0);
- apr_atomic_inc32(&(queue_info->idlers)); /* back out dec */
- return rv;
- }
- /* Re-check the idle worker count to guard against a
- * race condition. Now that we're in the mutex-protected
- * region, one of two things may have happened:
- * - If the idle worker count is still negative, the
- * workers are all still busy, so it's safe to
- * block on a condition variable.
- * - If the idle worker count is non-negative, then a
- * worker has become idle since the first check
- * of queue_info->idlers above. It's possible
- * that the worker has also signaled the condition
- * variable--and if so, the listener missed it
- * because it wasn't yet blocked on the condition
- * variable. But if the idle worker count is
- * now non-negative, it's safe for this function to
- * return immediately.
- *
- * A "negative value" (relative to zero_pt) in
- * queue_info->idlers tells how many
- * threads are waiting on an idle worker.
- */
- if (queue_info->idlers < zero_pt) {
- if (had_to_block) {
- *had_to_block = 1;
- }
- rv = apr_thread_cond_wait(queue_info->wait_for_idler,
- queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- apr_status_t rv2;
- AP_DEBUG_ASSERT(0);
- rv2 = apr_thread_mutex_unlock(queue_info->idlers_mutex);
- if (rv2 != APR_SUCCESS) {
- return rv2;
- }
- return rv;
- }
- }
- rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- }
-
- if (queue_info->terminated) {
- return APR_EOF;
- }
- else {
- return APR_SUCCESS;
- }
-}
-
-apr_uint32_t ap_queue_info_num_idlers(fd_queue_info_t *queue_info)
-{
- apr_uint32_t val;
- val = apr_atomic_read32(&queue_info->idlers);
- if (val <= zero_pt)
- return 0;
- return val - zero_pt;
-}
-
-void ap_push_pool(fd_queue_info_t *queue_info, apr_pool_t *pool_to_recycle)
-{
- struct recycled_pool *new_recycle;
- /* If we have been given a pool to recycle, atomically link
- * it into the queue_info's list of recycled pools
- */
- if (!pool_to_recycle)
- return;
-
- if (queue_info->max_recycled_pools >= 0) {
- apr_uint32_t cnt = apr_atomic_read32(&queue_info->recycled_pools_count);
- if (cnt >= queue_info->max_recycled_pools) {
- apr_pool_destroy(pool_to_recycle);
- return;
- }
- apr_atomic_inc32(&queue_info->recycled_pools_count);
- }
-
- apr_pool_clear(pool_to_recycle);
- new_recycle = apr_palloc(pool_to_recycle, sizeof *new_recycle);
- new_recycle->pool = pool_to_recycle;
- for (;;) {
- /*
- * Save queue_info->recycled_pool in local variable next because
- * new_recycle->next can be changed after apr_atomic_casptr
- * function call. For gory details see PR 44402.
- */
- struct recycled_pool *next = queue_info->recycled_pools;
- new_recycle->next = next;
- if (apr_atomic_casptr((void*) &(queue_info->recycled_pools),
- new_recycle, next) == next)
- break;
- }
-}
-
-void ap_pop_pool(apr_pool_t **recycled_pool, fd_queue_info_t *queue_info)
-{
- /* Atomically pop a pool from the recycled list */
-
- /* This function is safe only as long as it is single threaded because
- * it reaches into the queue and accesses "next" which can change.
- * We are OK today because it is only called from the listener thread.
- * cas-based pushes do not have the same limitation - any number can
- * happen concurrently with a single cas-based pop.
- */
-
- *recycled_pool = NULL;
-
-
- /* Atomically pop a pool from the recycled list */
- for (;;) {
- struct recycled_pool *first_pool = queue_info->recycled_pools;
- if (first_pool == NULL) {
- break;
- }
- if (apr_atomic_casptr((void *)&queue_info->recycled_pools,
- first_pool->next, first_pool) == first_pool) {
- *recycled_pool = first_pool->pool;
- if (queue_info->max_recycled_pools >= 0)
- apr_atomic_dec32(&queue_info->recycled_pools_count);
- break;
- }
- }
-}
-
-void ap_free_idle_pools(fd_queue_info_t *queue_info)
-{
- apr_pool_t *p;
-
- queue_info->max_recycled_pools = 0;
- for (;;) {
- ap_pop_pool(&p, queue_info);
- if (p == NULL)
- break;
- apr_pool_destroy(p);
- }
- apr_atomic_set32(&queue_info->recycled_pools_count, 0);
-}
-
-
-apr_status_t ap_queue_info_term(fd_queue_info_t *queue_info)
-{
- apr_status_t rv;
- rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- queue_info->terminated = 1;
- apr_thread_cond_broadcast(queue_info->wait_for_idler);
- return apr_thread_mutex_unlock(queue_info->idlers_mutex);
-}
-
-/**
- * Detects when the fd_queue_t is full. This utility function is expected
- * to be called from within critical sections, and is not threadsafe.
- */
-#define ap_queue_full(queue) ((queue)->nelts == (queue)->bounds)
-
-/**
- * Detects when the fd_queue_t is empty. This utility function is expected
- * to be called from within critical sections, and is not threadsafe.
- */
-#define ap_queue_empty(queue) ((queue)->nelts == 0 && APR_RING_EMPTY(&queue->timers ,timer_event_t, link))
-
-/**
- * Callback routine that is called to destroy this
- * fd_queue_t when its pool is destroyed.
- */
-static apr_status_t ap_queue_destroy(void *data)
-{
- fd_queue_t *queue = data;
-
- /* Ignore errors here, we can't do anything about them anyway.
- * XXX: We should at least try to signal an error here, it is
- * indicative of a programmer error. -aaron */
- apr_thread_cond_destroy(queue->not_empty);
- apr_thread_mutex_destroy(queue->one_big_mutex);
-
- return APR_SUCCESS;
-}
-
-/**
- * Initialize the fd_queue_t.
- */
-apr_status_t ap_queue_init(fd_queue_t *queue, int queue_capacity,
- apr_pool_t *a)
-{
- int i;
- apr_status_t rv;
-
- if ((rv = apr_thread_mutex_create(&queue->one_big_mutex,
- APR_THREAD_MUTEX_DEFAULT,
- a)) != APR_SUCCESS) {
- return rv;
- }
- if ((rv = apr_thread_cond_create(&queue->not_empty, a)) != APR_SUCCESS) {
- return rv;
- }
-
- APR_RING_INIT(&queue->timers, timer_event_t, link);
-
- queue->data = apr_palloc(a, queue_capacity * sizeof(fd_queue_elem_t));
- queue->bounds = queue_capacity;
- queue->nelts = 0;
- queue->in = 0;
- queue->out = 0;
-
- /* Set all the sockets in the queue to NULL */
- for (i = 0; i < queue_capacity; ++i)
- queue->data[i].sd = NULL;
-
- apr_pool_cleanup_register(a, queue, ap_queue_destroy,
- apr_pool_cleanup_null);
-
- return APR_SUCCESS;
-}
-
-/**
- * Push a new socket onto the queue.
- *
- * precondition: ap_queue_info_wait_for_idler has already been called
- * to reserve an idle worker thread
- */
-apr_status_t ap_queue_push(fd_queue_t *queue, apr_socket_t *sd,
- void *baton, apr_pool_t *p)
-{
- fd_queue_elem_t *elem;
- apr_status_t rv;
-
- if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
-
- AP_DEBUG_ASSERT(!queue->terminated);
- AP_DEBUG_ASSERT(!ap_queue_full(queue));
-
- elem = &queue->data[queue->in];
- queue->in++;
- if (queue->in >= queue->bounds)
- queue->in -= queue->bounds;
- elem->sd = sd;
- elem->baton = baton;
- elem->p = p;
- queue->nelts++;
-
- apr_thread_cond_signal(queue->not_empty);
-
- if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
-
- return APR_SUCCESS;
-}
-
-apr_status_t ap_queue_push_timer(fd_queue_t *queue, timer_event_t *te)
-{
- apr_status_t rv;
-
- if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
-
- AP_DEBUG_ASSERT(!queue->terminated);
-
- APR_RING_INSERT_TAIL(&queue->timers, te, timer_event_t, link);
-
- apr_thread_cond_signal(queue->not_empty);
-
- if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
-
- return APR_SUCCESS;
-}
-
-/**
- * Retrieves the next available socket from the queue. If there are no
- * sockets available, it will block until one becomes available.
- * Once retrieved, the socket is placed into the address specified by
- * 'sd'.
- */
-apr_status_t ap_queue_pop_something(fd_queue_t *queue, apr_socket_t **sd,
- void **baton, apr_pool_t **p,
- timer_event_t **te_out)
-{
- fd_queue_elem_t *elem;
- timer_event_t *te;
- apr_status_t rv;
-
- if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
-
- /* Keep waiting until we wake up and find that the queue is not empty. */
- if (ap_queue_empty(queue)) {
- if (!queue->terminated) {
- apr_thread_cond_wait(queue->not_empty, queue->one_big_mutex);
- }
- /* If we wake up and it's still empty, then we were interrupted */
- if (ap_queue_empty(queue)) {
- rv = apr_thread_mutex_unlock(queue->one_big_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- if (queue->terminated) {
- return APR_EOF; /* no more elements ever again */
- }
- else {
- return APR_EINTR;
- }
- }
- }
-
- te = NULL;
- if (te_out) {
- if (!APR_RING_EMPTY(&queue->timers, timer_event_t, link)) {
- te = APR_RING_FIRST(&queue->timers);
- APR_RING_REMOVE(te, link);
- }
- *te_out = te;
- }
- if (!te) {
- elem = &queue->data[queue->out];
- queue->out++;
- if (queue->out >= queue->bounds)
- queue->out -= queue->bounds;
- queue->nelts--;
- *sd = elem->sd;
- if (baton) {
- *baton = elem->baton;
- }
- *p = elem->p;
-#ifdef AP_DEBUG
- elem->sd = NULL;
- elem->p = NULL;
-#endif /* AP_DEBUG */
- }
-
- rv = apr_thread_mutex_unlock(queue->one_big_mutex);
- return rv;
-}
-
-static apr_status_t queue_interrupt(fd_queue_t *queue, int all, int term)
-{
- apr_status_t rv;
-
- if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
- /* we must hold one_big_mutex when setting this... otherwise,
- * we could end up setting it and waking everybody up just after a
- * would-be popper checks it but right before they block
- */
- if (term) {
- queue->terminated = 1;
- }
- if (all)
- apr_thread_cond_broadcast(queue->not_empty);
- else
- apr_thread_cond_signal(queue->not_empty);
- return apr_thread_mutex_unlock(queue->one_big_mutex);
-}
-
-apr_status_t ap_queue_interrupt_all(fd_queue_t *queue)
-{
- return queue_interrupt(queue, 1, 0);
-}
-
-apr_status_t ap_queue_interrupt_one(fd_queue_t *queue)
-{
- return queue_interrupt(queue, 0, 0);
-}
-
-apr_status_t ap_queue_term(fd_queue_t *queue)
-{
- return queue_interrupt(queue, 1, 1);
-}
-
#endif /* WIN32 */
projects / apache / commitdiff