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Posted to cvs@httpd.apache.org by yl...@apache.org on 2018/01/18 21:07:45 UTC
svn commit: r1821558 - in /httpd/httpd/trunk: CHANGES
server/mpm/event/event.c
Author: ylavic
Date: Thu Jan 18 21:07:45 2018
New Revision: 1821558
URL: http://svn.apache.org/viewvc?rev=1821558&view=rev
Log:
mod_event: Let the listener thread do its maintenance job on resources shortage.
PR 61979.
Modified:
httpd/httpd/trunk/CHANGES
httpd/httpd/trunk/server/mpm/event/event.c
Modified: httpd/httpd/trunk/CHANGES
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/CHANGES?rev=1821558&r1=1821557&r2=1821558&view=diff
==============================================================================
--- httpd/httpd/trunk/CHANGES [utf-8] (original)
+++ httpd/httpd/trunk/CHANGES [utf-8] Thu Jan 18 21:07:45 2018
@@ -1,6 +1,9 @@
-*- coding: utf-8 -*-
Changes with Apache 2.5.1
+ *) mod_event: Let the listener thread do its maintenance job on resources
+ shortage. PR 61979. [Yann Ylavic]
+
*) mod_headers: 'RequestHeader set|edit|edit_r Content-Type X' could
inadvertently modify the Content-Type _response_ header. Applies to
Content-Type only and likely to only affect static file responses.
Modified: httpd/httpd/trunk/server/mpm/event/event.c
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/server/mpm/event/event.c?rev=1821558&r1=1821557&r2=1821558&view=diff
==============================================================================
--- httpd/httpd/trunk/server/mpm/event/event.c (original)
+++ httpd/httpd/trunk/server/mpm/event/event.c Thu Jan 18 21:07:45 2018
@@ -184,7 +184,6 @@ static volatile int dying = 0;
static volatile int workers_may_exit = 0;
static volatile int start_thread_may_exit = 0;
static volatile int listener_may_exit = 0;
-static volatile int listeners_disabled = 0;
static int listener_is_wakeable = 0; /* Pollset supports APR_POLLSET_WAKEABLE */
static int num_listensocks = 0;
static apr_int32_t conns_this_child; /* MaxConnectionsPerChild, only access
@@ -472,6 +471,8 @@ static pid_t ap_my_pid; /* Linux
static pid_t parent_pid;
static apr_os_thread_t *listener_os_thread;
+static int ap_child_slot; /* Current child process slot in scoreboard */
+
/* The LISTENER_SIGNAL signal will be sent from the main thread to the
* listener thread to wake it up for graceful termination (what a child
* process from an old generation does when the admin does "apachectl
@@ -485,23 +486,29 @@ static apr_os_thread_t *listener_os_thre
*/
static apr_socket_t **worker_sockets;
-static void disable_listensocks(int process_slot)
+static volatile apr_uint32_t listensocks_disabled;
+
+static void disable_listensocks(void)
{
int i;
- listeners_disabled = 1;
- for (i = 0; i < num_listensocks; i++) {
- apr_pollset_remove(event_pollset, &listener_pollfd[i]);
+ if (apr_atomic_cas32(&listensocks_disabled, 1, 0) != 0) {
+ return;
+ }
+ if (event_pollset) {
+ for (i = 0; i < num_listensocks; i++) {
+ apr_pollset_remove(event_pollset, &listener_pollfd[i]);
+ }
}
- ap_scoreboard_image->parent[process_slot].not_accepting = 1;
+ ap_scoreboard_image->parent[ap_child_slot].not_accepting = 1;
}
-static void enable_listensocks(int process_slot)
+static void enable_listensocks(void)
{
int i;
- if (listener_may_exit) {
+ if (listener_may_exit
+ || apr_atomic_cas32(&listensocks_disabled, 0, 1) != 1) {
return;
}
- listeners_disabled = 0;
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00457)
"Accepting new connections again: "
"%u active conns (%u lingering/%u clogged/%u suspended), "
@@ -517,7 +524,12 @@ static void enable_listensocks(int proce
* XXX: This is not yet optimal. If many workers suddenly become available,
* XXX: the parent may kill some processes off too soon.
*/
- ap_scoreboard_image->parent[process_slot].not_accepting = 0;
+ ap_scoreboard_image->parent[ap_child_slot].not_accepting = 0;
+}
+
+static APR_INLINE apr_uint32_t listeners_disabled(void)
+{
+ return apr_atomic_read32(&listensocks_disabled);
}
static APR_INLINE int connections_above_limit(void)
@@ -527,9 +539,9 @@ static APR_INLINE int connections_above_
apr_uint32_t c_count = apr_atomic_read32(&connection_count);
apr_uint32_t l_count = apr_atomic_read32(&lingering_count);
if (c_count <= l_count
- /* Off by 'listeners_disabled' to avoid flip flop */
+ /* Off by 'listeners_disabled()' to avoid flip flop */
|| c_count - l_count < (apr_uint32_t)threads_per_child +
- (i_count - (listeners_disabled != 0)) *
+ (i_count - listeners_disabled()) *
(worker_factor / WORKER_FACTOR_SCALE)) {
return 0;
}
@@ -592,6 +604,7 @@ static void close_worker_sockets(void)
static void wakeup_listener(void)
{
listener_may_exit = 1;
+ disable_listensocks();
/* Unblock the listener if it's poll()ing */
if (event_pollset && listener_is_wakeable) {
@@ -795,7 +808,7 @@ static apr_status_t decrement_connection
is_last_connection = !apr_atomic_dec32(&connection_count);
if (listener_is_wakeable
&& ((is_last_connection && listener_may_exit)
- || (listeners_disabled && !connections_above_limit()))) {
+ || (listeners_disabled() && !connections_above_limit()))) {
apr_pollset_wakeup(event_pollset);
}
return APR_SUCCESS;
@@ -1272,17 +1285,16 @@ static void check_infinite_requests(void
}
}
-static void close_listeners(int process_slot, int *closed)
+static void close_listeners(int *closed)
{
if (!*closed) {
int i;
- disable_listensocks(process_slot);
ap_close_listeners_ex(my_bucket->listeners);
*closed = 1;
dying = 1;
- ap_scoreboard_image->parent[process_slot].quiescing = 1;
+ ap_scoreboard_image->parent[ap_child_slot].quiescing = 1;
for (i = 0; i < threads_per_child; ++i) {
- ap_update_child_status_from_indexes(process_slot, i,
+ ap_update_child_status_from_indexes(ap_child_slot, i,
SERVER_GRACEFUL, NULL);
}
/* wake up the main thread */
@@ -1796,8 +1808,9 @@ static void * APR_THREAD_FUNC listener_t
ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf,
APLOGNO(03266)
"failed to initialize pollset, "
- "attempting to shutdown process gracefully");
- signal_threads(ST_GRACEFUL);
+ "shutdown process now");
+ resource_shortage = 1;
+ signal_threads(ST_UNGRACEFUL);
return NULL;
}
@@ -1819,7 +1832,7 @@ static void * APR_THREAD_FUNC listener_t
check_infinite_requests();
if (listener_may_exit) {
- close_listeners(process_slot, &closed);
+ close_listeners(&closed);
if (terminate_mode == ST_UNGRACEFUL
|| apr_atomic_read32(&connection_count) == 0)
break;
@@ -1928,7 +1941,7 @@ static void * APR_THREAD_FUNC listener_t
* need to update timeouts (logic is above, so simply restart
* the loop).
*/
- if (!listener_may_exit && !listeners_disabled) {
+ if (!listener_may_exit && !listeners_disabled()) {
continue;
}
timeout_time = 0;
@@ -1944,13 +1957,13 @@ static void * APR_THREAD_FUNC listener_t
}
if (listener_may_exit) {
- close_listeners(process_slot, &closed);
+ close_listeners(&closed);
if (terminate_mode == ST_UNGRACEFUL
|| apr_atomic_read32(&connection_count) == 0)
break;
}
- while (num) {
+ for (; num; --num, ++out_pfd) {
listener_poll_type *pt = (listener_poll_type *) out_pfd->client_data;
if (pt->type == PT_CSD) {
/* one of the sockets is readable */
@@ -2011,17 +2024,17 @@ static void * APR_THREAD_FUNC listener_t
ap_assert(0);
}
}
- else if (pt->type == PT_ACCEPT && !listeners_disabled) {
+ else if (pt->type == PT_ACCEPT && !listeners_disabled()) {
/* A Listener Socket is ready for an accept() */
if (workers_were_busy) {
- disable_listensocks(process_slot);
+ disable_listensocks();
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
APLOGNO(03268)
"All workers busy, not accepting new conns "
"in this process");
}
else if (connections_above_limit()) {
- disable_listensocks(process_slot);
+ disable_listensocks();
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
APLOGNO(03269)
"Too many open connections (%u), "
@@ -2050,8 +2063,9 @@ static void * APR_THREAD_FUNC listener_t
ap_server_conf, APLOGNO(03097)
"Failed to create transaction pool");
apr_allocator_destroy(allocator);
+ resource_shortage = 1;
signal_threads(ST_GRACEFUL);
- return NULL;
+ continue;
}
apr_allocator_owner_set(allocator, ptrans);
}
@@ -2120,9 +2134,7 @@ static void * APR_THREAD_FUNC listener_t
push_timer2worker(te);
}
}
- out_pfd++;
- num--;
- } /* while for processing poll */
+ } /* for processing poll */
/* XXX possible optimization: stash the current time for use as
* r->request_time for new requests
@@ -2194,14 +2206,14 @@ static void * APR_THREAD_FUNC listener_t
}
}
- if (listeners_disabled
+ if (listeners_disabled()
&& !workers_were_busy
&& !connections_above_limit()) {
- enable_listensocks(process_slot);
+ enable_listensocks();
}
} /* listener main loop */
- close_listeners(process_slot, &closed);
+ close_listeners(&closed);
ap_queue_term(worker_queue);
apr_thread_exit(thd, APR_SUCCESS);
@@ -2652,6 +2664,7 @@ static void child_main(int child_num_arg
retained->mpm->mpm_state = AP_MPMQ_STARTING;
ap_my_pid = getpid();
+ ap_child_slot = child_num_arg;
ap_fatal_signal_child_setup(ap_server_conf);
apr_pool_create(&pchild, pconf);
@@ -3630,6 +3643,7 @@ static int event_pre_config(apr_pool_t *
event_pollset = NULL;
worker_queue_info = NULL;
listener_os_thread = NULL;
+ listensocks_disabled = 0;
return OK;
}