Mailing List Archive

Author: ylavic
Date: Fri Apr 12 11:02:31 2024
New Revision: 1916926

URL: http://svn.apache.org/viewvc?rev=1916926&view=rev
Log:
mpm_worker: Fix AH00045 about children processes not terminating timely.

* server/mpm/worker/worker.c(setup_threads_runtime):
Create pollset with APR_POLLSET_WAKEABLE to be able to wake up the listener
when stopping.

* server/mpm/worker/worker.c(wakeup_listener):
Wake up the listener using the wakeup pipe (apr_pollset_wakeup).

* server/mpm/worker/worker.c(join_workers):
Like mpm_event, don't depend on `pthread_kill(listener_thread, 0)` to check
whether the listener has exited (this does not work on some systems), but use
the "dying" global variable instead which is set by the listener just before
exiting.


Added:
httpd/httpd/trunk/changes-entries/worker_exit.txt
Modified:
httpd/httpd/trunk/server/mpm/worker/worker.c

Added: httpd/httpd/trunk/changes-entries/worker_exit.txt
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/changes-entries/worker_exit.txt?rev=1916926&view=auto
==============================================================================
--- httpd/httpd/trunk/changes-entries/worker_exit.txt (added)
+++ httpd/httpd/trunk/changes-entries/worker_exit.txt Fri Apr 12 11:02:31 2024
@@ -0,0 +1,2 @@
+ *) mpm_worker: Fix possible warning (AH00045) about children processes not
+ terminating timely. [Yann Ylavic]

Modified: httpd/httpd/trunk/server/mpm/worker/worker.c
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/server/mpm/worker/worker.c?rev=1916926&r1=1916925&r2=1916926&view=diff
==============================================================================
--- httpd/httpd/trunk/server/mpm/worker/worker.c (original)
+++ httpd/httpd/trunk/server/mpm/worker/worker.c Fri Apr 12 11:02:31 2024
@@ -126,10 +126,11 @@ static int max_workers = 0;
static int server_limit = 0;
static int thread_limit = 0;
static int had_healthy_child = 0;
-static int dying = 0;
+static volatile int dying = 0;
static int workers_may_exit = 0;
static int start_thread_may_exit = 0;
static int listener_may_exit = 0;
+static int listener_is_wakeable = 0; /* Pollset supports APR_POLLSET_WAKEABLE */
static int requests_this_child;
static int num_listensocks = 0;
static int resource_shortage = 0;
@@ -276,6 +277,15 @@ static void close_worker_sockets(void)
static void wakeup_listener(void)
{
listener_may_exit = 1;
+
+ /* Unblock the listener if it's poll()ing */
+ if (worker_pollset && listener_is_wakeable) {
+ apr_pollset_wakeup(worker_pollset);
+ }
+
+ /* unblock the listener if it's waiting for a worker */
+ ap_queue_info_term(worker_queue_info);
+
if (!listener_os_thread) {
/* XXX there is an obscure path that this doesn't handle perfectly:
* right after listener thread is created but before
@@ -284,10 +294,6 @@ static void wakeup_listener(void)
*/
return;
}
-
- /* unblock the listener if it's waiting for a worker */
- ap_queue_info_term(worker_queue_info);
-
/*
* we should just be able to "kill(ap_my_pid, LISTENER_SIGNAL)" on all
* platforms and wake up the listener thread since it is the only thread
@@ -870,6 +876,7 @@ static void create_listener_thread(threa
static void setup_threads_runtime(void)
{
ap_listen_rec *lr;
+ int pollset_flags;
apr_status_t rv;

/* All threads (listener, workers) and synchronization objects (queues,
@@ -903,8 +910,17 @@ static void setup_threads_runtime(void)
}

/* Create the main pollset */
- rv = apr_pollset_create(&worker_pollset, num_listensocks, pruntime,
- APR_POLLSET_NOCOPY);
+ pollset_flags = APR_POLLSET_NOCOPY | APR_POLLSET_WAKEABLE;
+ rv = apr_pollset_create(&worker_pollset, num_listensocks + 1, pruntime,
+ pollset_flags);
+ if (rv == APR_SUCCESS) {
+ listener_is_wakeable = 1;
+ }
+ else {
+ pollset_flags &= ~APR_POLLSET_WAKEABLE;
+ rv = apr_pollset_create(&worker_pollset, num_listensocks, pruntime,
+ pollset_flags);
+ }
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(03285)
"Couldn't create pollset in thread;"
@@ -1058,19 +1074,17 @@ static void join_workers(apr_thread_t *l
*/

iter = 0;
- while (iter < 10 &&
-#ifdef HAVE_PTHREAD_KILL
- pthread_kill(*listener_os_thread, 0)
-#else
- kill(ap_my_pid, 0)
-#endif
- == 0) {
- /* listener not dead yet */
- apr_sleep(apr_time_make(0, 500000));
+ while (!dying) {
+ apr_sleep(apr_time_from_msec(500));
+ if (dying || ++iter > 10) {
+ break;
+ }
+ /* listener has not stopped accepting yet */
+ ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
+ "listener has not stopped accepting yet (%d iter)", iter);
wakeup_listener();
- ++iter;
}
- if (iter >= 10) {
+ if (iter > 10) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00276)
"the listener thread didn't exit");
}