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Revert r1821526, r1821527, r1821534, r1821538, r1821539, r1821541, r1821605, r1821607, r1821608.

Browse Source 
Instead of copying event/fdqueue.c code into existing mpm_unix.c, losing all
contributors (blame, since r105919...), will restart the series by svn-moving
event/fdqueue.[ch] to server/mpm_fdqueue.[ch] first.

The code is not really unix specific either, so this sounds better.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1821619 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Yann Ylavic
2018-01-19 11:29:00 +00:00
parent 8f45a56cee
commit ff2d0af6cb
9 changed files with 1064 additions and 586 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
server/mpm/event/config3.m4
View File

@@ -8,7 +8,7 @@ if test "$ac_cv_serf" = yes ; then
fi fi
APACHE_SUBST(MOD_MPM_EVENT_LDADD) 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) AC_CHECK_FUNCS(pthread_kill)
], , [\$(MOD_MPM_EVENT_LDADD)]) ], , [\$(MOD_MPM_EVENT_LDADD)])

13
server/mpm/event/event.c
View File

@@ -91,7 +91,7 @@
#include "mpm_common.h" #include "mpm_common.h"
#include "ap_listen.h" #include "ap_listen.h"
#include "scoreboard.h" #include "scoreboard.h"
#include "mpm_unix.h" #include "fdqueue.h"
#include "mpm_default.h" #include "mpm_default.h"
#include "http_vhost.h" #include "http_vhost.h"
#include "unixd.h" #include "unixd.h"
@@ -219,8 +219,6 @@ static apr_pollfd_t *listener_pollfd;
*/ */
static apr_pollset_t *event_pollset; 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), * The chain of connections to be shutdown by a worker thread (deferred),
* linked list updated atomically. * linked list updated atomically.
@@ -517,7 +515,7 @@ static void enable_listensocks(void)
apr_atomic_read32(&lingering_count), apr_atomic_read32(&lingering_count),
apr_atomic_read32(&clogged_count), apr_atomic_read32(&clogged_count),
apr_atomic_read32(&suspended_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++) for (i = 0; i < num_listensocks; i++)
apr_pollset_add(event_pollset, &listener_pollfd[i]); apr_pollset_add(event_pollset, &listener_pollfd[i]);
/* /*
@@ -534,7 +532,7 @@ static APR_INLINE apr_uint32_t listeners_disabled(void)
static APR_INLINE int connections_above_limit(void) 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) { if (i_count > 0) {
apr_uint32_t c_count = apr_atomic_read32(&connection_count); apr_uint32_t c_count = apr_atomic_read32(&connection_count);
apr_uint32_t l_count = apr_atomic_read32(&lingering_count); apr_uint32_t l_count = apr_atomic_read32(&lingering_count);
@@ -2042,7 +2040,7 @@ static void * APR_THREAD_FUNC listener_thread(apr_thread_t * thd, void *dummy)
apr_atomic_read32(&connection_count)); apr_atomic_read32(&connection_count));
ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf, ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
"Idle workers: %u", "Idle workers: %u",
ap_queue_info_num_idlers(worker_queue_info)); ap_queue_info_get_idlers(worker_queue_info));
workers_were_busy = 1; workers_were_busy = 1;
} }
else if (!listener_may_exit) { else if (!listener_may_exit) {
@@ -2309,8 +2307,7 @@ static void *APR_THREAD_FUNC worker_thread(apr_thread_t * thd, void *dummy)
break; break;
} }
rv = ap_queue_pop_something(worker_queue, &csd, (void **)&cs, rv = ap_queue_pop_something(worker_queue, &csd, &cs, &ptrans, &te);
&ptrans, &te);
if (rv != APR_SUCCESS) { if (rv != APR_SUCCESS) {
/* We get APR_EOF during a graceful shutdown once all the /* We get APR_EOF during a graceful shutdown once all the

524
server/mpm/event/fdqueue.c Normal file
View File

@@ -0,0 +1,524 @@
/* 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);
}

87
server/mpm_unix.h → server/mpm/event/fdqueue.h
View File

@@ -15,43 +15,52 @@
*/ */
/** /**
* @file mpm_unix.h * @file event/fdqueue.h
* @brief fd queue declarations * @brief fd queue declarations
* *
* @defgroup APACHE_MPM Multi-Processing Modules * @addtogroup APACHE_MPM_EVENT
* @ingroup APACHE
* @{ * @{
*/ */
#ifndef MPM_UNIX_H #ifndef FDQUEUE_H
#define MPM_UNIX_H #define FDQUEUE_H
#include "httpd.h"
#ifndef WIN32 #include <stdlib.h>
#if APR_HAVE_UNISTD_H
#include <apr.h> #include <unistd.h>
#include <apr_ring.h> #endif
#include <apr_pools.h>
#include <apr_network_io.h>
#include <apr_thread_mutex.h> #include <apr_thread_mutex.h>
#include <apr_thread_cond.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" #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_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_status_t ap_queue_info_create(fd_queue_info_t ** queue_info,
apr_pool_t *pool, int max_idlers, apr_pool_t * pool, int max_idlers,
int max_recycled_pools); int max_recycled_pools);
apr_status_t ap_queue_info_set_idle(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_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_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_wait_for_idler(fd_queue_info_t * queue_info,
int *had_to_block); 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 timer_event_t timer_event_t;
@@ -79,25 +88,21 @@ struct fd_queue_t
}; };
typedef struct fd_queue_t fd_queue_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_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_push_pool(fd_queue_info_t * queue_info,
void ap_free_idle_pools(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_status_t ap_queue_init(fd_queue_t * queue, int queue_capacity,
apr_pool_t *a); apr_pool_t * a);
apr_status_t ap_queue_push(fd_queue_t *queue, apr_socket_t *sd, apr_status_t ap_queue_push(fd_queue_t * queue, apr_socket_t * sd,
void *baton, apr_pool_t *p); 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_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, apr_status_t ap_queue_pop_something(fd_queue_t * queue, apr_socket_t ** sd,
void **baton, apr_pool_t **p, event_conn_state_t ** ecs, apr_pool_t ** p,
timer_event_t **te); timer_event_t ** te);
#define ap_queue_pop(q_, s_, p_) \ apr_status_t ap_queue_interrupt_all(fd_queue_t * queue);
ap_queue_pop_something((q_), (s_), NULL, (p_), NULL) apr_status_t ap_queue_interrupt_one(fd_queue_t * queue);
apr_status_t ap_queue_interrupt_all(fd_queue_t *queue); apr_status_t ap_queue_term(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 */ #endif /* FDQUEUE_H */
#endif /* MPM_UNIX_H */
/** @} */ /** @} */

2
server/mpm/worker/config3.m4
View File

@@ -1,7 +1,7 @@
APACHE_MPMPATH_INIT(worker) APACHE_MPMPATH_INIT(worker)
dnl ## XXX - Need a more thorough check of the proper flags to use 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) AC_CHECK_FUNCS(pthread_kill)
]) ])

401
server/mpm/worker/fdqueue.c Normal file
View File

@@ -0,0 +1,401 @@
/* 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);
}

75
server/mpm/worker/fdqueue.h Normal file
View File

@@ -0,0 +1,75 @@
/* 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 */
/** @} */

16
server/mpm/worker/worker.c
View File

@@ -64,7 +64,7 @@
#include "mpm_common.h" #include "mpm_common.h"
#include "ap_listen.h" #include "ap_listen.h"
#include "scoreboard.h" #include "scoreboard.h"
#include "mpm_unix.h" #include "fdqueue.h"
#include "mpm_default.h" #include "mpm_default.h"
#include "util_mutex.h" #include "util_mutex.h"
#include "unixd.h" #include "unixd.h"
@@ -597,7 +597,11 @@ static void * APR_THREAD_FUNC listener_thread(apr_thread_t *thd, void * dummy)
if (listener_may_exit) break; if (listener_may_exit) break;
if (!have_idle_worker) { 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)) { if (APR_STATUS_IS_EOF(rv)) {
break; /* we've been signaled to die now */ break; /* we've been signaled to die now */
} }
@@ -675,8 +679,6 @@ static void * APR_THREAD_FUNC listener_thread(apr_thread_t *thd, void * dummy)
} /* if/else */ } /* if/else */
if (!listener_may_exit) { if (!listener_may_exit) {
/* the following pops a recycled ptrans pool off a stack */
ap_pop_pool(&ptrans, worker_queue_info);
if (ptrans == NULL) { if (ptrans == NULL) {
/* we can't use a recycled transaction pool this time. /* we can't use a recycled transaction pool this time.
* create a new transaction pool */ * create a new transaction pool */
@@ -686,8 +688,8 @@ static void * APR_THREAD_FUNC listener_thread(apr_thread_t *thd, void * dummy)
apr_allocator_max_free_set(allocator, ap_max_mem_free); apr_allocator_max_free_set(allocator, ap_max_mem_free);
apr_pool_create_ex(&ptrans, pconf, NULL, allocator); apr_pool_create_ex(&ptrans, pconf, NULL, allocator);
apr_allocator_owner_set(allocator, ptrans); apr_allocator_owner_set(allocator, ptrans);
apr_pool_tag(ptrans, "transaction");
} }
apr_pool_tag(ptrans, "transaction");
rv = lr->accept_func(&csd, lr, ptrans); rv = lr->accept_func(&csd, lr, ptrans);
/* later we trash rv and rely on csd to indicate success/failure */ /* later we trash rv and rely on csd to indicate success/failure */
AP_DEBUG_ASSERT(rv == APR_SUCCESS || !csd); AP_DEBUG_ASSERT(rv == APR_SUCCESS || !csd);
@@ -710,7 +712,7 @@ static void * APR_THREAD_FUNC listener_thread(apr_thread_t *thd, void * dummy)
accept_mutex_error("unlock", rv, process_slot); accept_mutex_error("unlock", rv, process_slot);
} }
if (csd != NULL) { if (csd != NULL) {
rv = ap_queue_push(worker_queue, csd, NULL, ptrans); rv = ap_queue_push(worker_queue, csd, ptrans);
if (rv) { if (rv) {
/* trash the connection; we couldn't queue the connected /* trash the connection; we couldn't queue the connected
* socket to a worker * socket to a worker
@@ -916,7 +918,7 @@ static void * APR_THREAD_FUNC start_threads(apr_thread_t *thd, void *dummy)
} }
rv = ap_queue_info_create(&worker_queue_info, pchild, rv = ap_queue_info_create(&worker_queue_info, pchild,
threads_per_child, -1); threads_per_child);
if (rv != APR_SUCCESS) { if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03141) ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03141)
"ap_queue_info_create() failed"); "ap_queue_info_create() failed");

530
server/mpm_unix.c
View File

@@ -27,8 +27,7 @@
#ifndef WIN32 #ifndef WIN32
#include "mpm_unix.h" #include "apr.h"
#include "apr_thread_proc.h" #include "apr_thread_proc.h"
#include "apr_signal.h" #include "apr_signal.h"
#include "apr_strings.h" #include "apr_strings.h"
@@ -37,8 +36,6 @@
#include "apr_getopt.h" #include "apr_getopt.h"
#include "apr_optional.h" #include "apr_optional.h"
#include "apr_allocator.h" #include "apr_allocator.h"
#include "apr_atomic.h"
#include "apr_errno.h"
#include "httpd.h" #include "httpd.h"
#include "http_config.h" #include "http_config.h"
@@ -46,6 +43,7 @@
#include "http_log.h" #include "http_log.h"
#include "http_main.h" #include "http_main.h"
#include "mpm_common.h" #include "mpm_common.h"
#include "ap_mpm.h"
#include "ap_listen.h" #include "ap_listen.h"
#include "scoreboard.h" #include "scoreboard.h"
#include "util_mutex.h" #include "util_mutex.h"
@@ -1106,528 +1104,4 @@ AP_DECLARE(apr_status_t) ap_fatal_signal_setup(server_rec *s,
return APR_SUCCESS; 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 */ #endif /* WIN32 */