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Posted to cvs@httpd.apache.org by rb...@apache.org on 2002/02/11 05:56:11 UTC
cvs commit: httpd-2.0/server/mpm/worker pod.c pod.h Makefile.in mpm.h worker.c
rbb 02/02/10 20:56:11
Modified: . CHANGES
server/mpm/worker Makefile.in mpm.h worker.c
Added: server/mpm/worker pod.c pod.h
Log:
Remove all signal handling from the worker MPM's child processes. Instead,
we use the pipe of death for all communication between parent and child.
Revision Changes Path
1.573 +4 -0 httpd-2.0/CHANGES
Index: CHANGES
===================================================================
RCS file: /home/cvs/httpd-2.0/CHANGES,v
retrieving revision 1.572
retrieving revision 1.573
diff -u -r1.572 -r1.573
--- CHANGES 10 Feb 2002 14:21:44 -0000 1.572
+++ CHANGES 11 Feb 2002 04:56:09 -0000 1.573
@@ -1,5 +1,9 @@
Changes with Apache 2.0.32-dev
+ *) Remove all signals from the worker MPM's child process. Instead,
+ the parent uses the Pipe of Death for all communication with the
+ child processes. [Ryan Bloom]
+
*) Fix prefork to not kill the parent if a child hits a resource shortage
on accept(). [Greg Ames]
1.2 +1 -1 httpd-2.0/server/mpm/worker/Makefile.in
Index: Makefile.in
===================================================================
RCS file: /home/cvs/httpd-2.0/server/mpm/worker/Makefile.in,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -r1.1 -r1.2
--- Makefile.in 30 Jul 2001 05:02:53 -0000 1.1
+++ Makefile.in 11 Feb 2002 04:56:10 -0000 1.2
@@ -1,5 +1,5 @@
LTLIBRARY_NAME = libworker.la
-LTLIBRARY_SOURCES = worker.c fdqueue.c
+LTLIBRARY_SOURCES = worker.c fdqueue.c pod.c
include $(top_srcdir)/build/ltlib.mk
1.10 +0 -1 httpd-2.0/server/mpm/worker/mpm.h
Index: mpm.h
===================================================================
RCS file: /home/cvs/httpd-2.0/server/mpm/worker/mpm.h,v
retrieving revision 1.9
retrieving revision 1.10
diff -u -r1.9 -r1.10
--- mpm.h 30 Jan 2002 06:34:12 -0000 1.9
+++ mpm.h 11 Feb 2002 04:56:10 -0000 1.10
@@ -76,7 +76,6 @@
#define AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
#define AP_MPM_DISABLE_NAGLE_ACCEPTED_SOCK
-#define AP_MPM_USES_POD 1
#define MPM_SYNC_CHILD_TABLE() (ap_sync_scoreboard_image())
#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
#define MPM_NOTE_CHILD_KILLED(i) (MPM_CHILD_PID(i) = 0)
1.73 +33 -55 httpd-2.0/server/mpm/worker/worker.c
Index: worker.c
===================================================================
RCS file: /home/cvs/httpd-2.0/server/mpm/worker/worker.c,v
retrieving revision 1.72
retrieving revision 1.73
diff -u -r1.72 -r1.73
--- worker.c 5 Feb 2002 23:17:22 -0000 1.72
+++ worker.c 11 Feb 2002 04:56:10 -0000 1.73
@@ -101,6 +101,7 @@
#include "http_core.h" /* for get_remote_host */
#include "http_connection.h"
#include "ap_mpm.h"
+#include "pod.h"
#include "mpm_common.h"
#include "ap_listen.h"
#include "scoreboard.h"
@@ -695,10 +696,6 @@
rv);
}
}
- if (ap_mpm_pod_check(pod) == APR_SUCCESS) {
- signal_workers();
- break;
- }
}
else {
if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(accept_mutex)))
@@ -760,16 +757,6 @@
return NULL;
}
-static int check_signal(int signum)
-{
- switch (signum) {
- case SIGTERM:
- case SIGINT:
- return 1;
- }
- return 0;
-}
-
static void * APR_THREAD_FUNC start_threads(apr_thread_t *thd, void *dummy)
{
thread_starter *ts = dummy;
@@ -893,6 +880,10 @@
/* done with init critical section */
+ /* Just use the standard apr_setup_signal_thread to block all signals
+ * from being received. The child processes no longer use signals for
+ * any communication with the parent process.
+ */
rv = apr_setup_signal_thread();
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
@@ -947,24 +938,28 @@
clean_child_exit(APEXIT_CHILDFATAL);
}
- apr_signal_thread(check_signal);
+ /* Watch for any messages from the parent over the POD */
+ while (1) {
+ rv = ap_mpm_pod_check(pod);
+ if (rv == AP_GRACEFUL || rv == AP_RESTART) {
+ signal_workers();
+ break;
+ }
+ }
- signal_workers(); /* helps us terminate a little more quickly when
- * the dispatch of the signal thread
- * beats the Pipe of Death and the browsers
- */
-
- /* A terminating signal was received. Now join each of the workers to
- * clean them up.
- * If the worker already exited, then the join frees their resources
- * and returns.
- * If the worker hasn't exited, then this blocks until they have (then
- * cleans up).
- */
- apr_thread_join(&rv, start_thread_id);
- for (i = 0; i < ap_threads_per_child; i++) {
- if (threads[i]) { /* if we ever created this thread */
- apr_thread_join(&rv, threads[i]);
+ if (rv == AP_GRACEFUL) {
+ /* A terminating signal was received. Now join each of the workers to
+ * clean them up.
+ * If the worker already exited, then the join frees their resources
+ * and returns.
+ * If the worker hasn't exited, then this blocks until they have (then
+ * cleans up).
+ */
+ apr_thread_join(&rv, start_thread_id);
+ for (i = 0; i < ap_threads_per_child; i++) {
+ if (threads[i]) { /* if we ever created this thread */
+ apr_thread_join(&rv, threads[i]);
+ }
}
}
@@ -1029,16 +1024,6 @@
return 0;
}
-/* If there aren't many connections coming in from the network, the child
- * processes may need to be awakened from their network i/o waits.
- * The pipe of death is an effective prod.
- */
-
-static void wake_up_and_die(void)
-{
- ap_mpm_pod_killpg(pod, ap_daemons_limit);
-}
-
/* start up a bunch of children */
static void startup_children(int number_to_start)
{
@@ -1158,7 +1143,7 @@
if (idle_thread_count > max_spare_threads) {
/* Kill off one child */
- ap_mpm_pod_signal(pod);
+ ap_mpm_pod_signal(pod, TRUE);
idle_spawn_rate = 1;
}
else if (idle_thread_count < min_spare_threads) {
@@ -1373,12 +1358,7 @@
/* Time to gracefully shut down:
* Kill child processes, tell them to call child_exit, etc...
*/
- wake_up_and_die();
-
- if (ap_os_killpg(getpgrp(), SIGTERM) < 0) {
- ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
- "killpg SIGTERM");
- }
+ ap_mpm_pod_killpg(pod, ap_daemons_limit, TRUE);
ap_reclaim_child_processes(1); /* Start with SIGTERM */
if (!child_fatal) {
@@ -1413,12 +1393,12 @@
ap_scoreboard_image->global->running_generation = ap_my_generation;
update_scoreboard_global();
- /* wake up the children...time to die. But we'll have more soon */
- wake_up_and_die();
-
if (is_graceful) {
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
AP_SIG_GRACEFUL_STRING " received. Doing graceful restart");
+ /* wake up the children...time to die. But we'll have more soon */
+ ap_mpm_pod_killpg(pod, ap_daemons_limit, TRUE);
+
/* This is mostly for debugging... so that we know what is still
* gracefully dealing with existing request.
@@ -1430,10 +1410,8 @@
* and a SIGHUP, we may as well use the same signal, because some user
* pthreads are stealing signals from us left and right.
*/
- if (ap_os_killpg(getpgrp(), SIGTERM) < 0) {
- ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
- "killpg SIGTERM");
- }
+ ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
+
ap_reclaim_child_processes(1); /* Start with SIGTERM */
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
"SIGHUP received. Attempting to restart");
1.1 httpd-2.0/server/mpm/worker/pod.c
Index: pod.c
===================================================================
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* Portions of this software are based upon public domain software
* originally written at the National Center for Supercomputing Applications,
* University of Illinois, Urbana-Champaign.
*/
#include "apr.h"
#include "apr_strings.h"
#include "apr_lock.h"
#define APR_WANT_STRFUNC
#include "apr_want.h"
#include "httpd.h"
#include "http_config.h"
#include "http_log.h"
#include "http_main.h"
#include "mpm.h"
#include "pod.h"
#include "mpm_common.h"
#include "ap_mpm.h"
#include "ap_listen.h"
#include "mpm_default.h"
AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t *p, ap_pod_t **pod)
{
apr_status_t rv;
*pod = apr_palloc(p, sizeof(**pod));
rv = apr_file_pipe_create(&((*pod)->pod_in), &((*pod)->pod_out), p);
if (rv != APR_SUCCESS) {
return rv;
}
/*
apr_file_pipe_timeout_set((*pod)->pod_in, 0);
*/
(*pod)->p = p;
apr_sockaddr_info_get(&(*pod)->sa, ap_listeners->bind_addr->hostname,
APR_UNSPEC, ap_listeners->bind_addr->port, 0, p);
return APR_SUCCESS;
}
AP_DECLARE(int) ap_mpm_pod_check(ap_pod_t *pod)
{
char c;
apr_size_t len = 1;
apr_status_t rv;
rv = apr_file_read(pod->pod_in, &c, &len);
if ((rv == APR_SUCCESS) && (len ==1)) {
if (c == RESTART_CHAR) {
return AP_RESTART;
}
if (c == GRACEFUL_CHAR) {
return AP_GRACEFUL;
}
}
else if (rv != APR_SUCCESS) {
return rv;
}
return AP_NORESTART;
}
AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t *pod)
{
apr_status_t rv;
rv = apr_file_close(pod->pod_out);
if (rv != APR_SUCCESS) {
return rv;
}
rv = apr_file_close(pod->pod_in);
if (rv != APR_SUCCESS) {
return rv;
}
return rv;
}
static apr_status_t pod_signal_internal(ap_pod_t *pod, int graceful)
{
apr_status_t rv;
char char_of_death = graceful ? GRACEFUL_CHAR : RESTART_CHAR;
apr_size_t one = 1;
do {
rv = apr_file_write(pod->pod_out, &char_of_death, &one);
} while (APR_STATUS_IS_EINTR(rv));
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf,
"write pipe_of_death");
}
return rv;
}
/* This function connects to the server, then immediately closes the connection.
* This permits the MPM to skip the poll when there is only one listening
* socket, because it provides a alternate way to unblock an accept() when
* the pod is used.
*/
static apr_status_t dummy_connection(ap_pod_t *pod)
{
apr_status_t rv;
apr_socket_t *sock;
apr_pool_t *p;
/* create a temporary pool for the socket. pconf stays around too long */
rv = apr_pool_create(&p, pod->p);
if (rv != APR_SUCCESS) {
return rv;
}
rv = apr_socket_create(&sock, pod->sa->family, SOCK_STREAM, p);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf,
"get socket to connect to listener");
return rv;
}
/* on some platforms (e.g., FreeBSD), the kernel won't accept many
* queued connections before it starts blocking local connects...
* we need to keep from blocking too long and instead return an error,
* because the MPM won't want to hold up a graceful restart for a
* long time
*/
rv = apr_setsocketopt(sock, APR_SO_TIMEOUT, 3 * APR_USEC_PER_SEC);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf,
"set timeout on socket to connect to listener");
return rv;
}
rv = apr_connect(sock, pod->sa);
if (rv != APR_SUCCESS) {
int log_level = APLOG_WARNING;
if (APR_STATUS_IS_TIMEUP(rv)) {
/* probably some server processes bailed out already and there
* is nobody around to call accept and clear out the kernel
* connection queue; usually this is not worth logging
*/
log_level = APLOG_DEBUG;
}
ap_log_error(APLOG_MARK, log_level, rv, ap_server_conf,
"connect to listener");
}
apr_socket_close(sock);
apr_pool_destroy(p);
return rv;
}
AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t *pod, int graceful)
{
apr_status_t rv;
rv = pod_signal_internal(pod, graceful);
if (rv != APR_SUCCESS) {
return rv;
}
return dummy_connection(pod);
}
AP_DECLARE(void) ap_mpm_pod_killpg(ap_pod_t *pod, int num, int graceful)
{
int i;
apr_status_t rv = APR_SUCCESS;
for (i = 0; i < num && rv == APR_SUCCESS; i++) {
rv = pod_signal_internal(pod, graceful);
}
if (rv == APR_SUCCESS) {
for (i = 0; i < num && rv == APR_SUCCESS; i++) {
rv = dummy_connection(pod);
}
}
}
1.1 httpd-2.0/server/mpm/worker/pod.h
Index: pod.h
===================================================================
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* Portions of this software are based upon public domain software
* originally written at the National Center for Supercomputing Applications,
* University of Illinois, Urbana-Champaign.
*/
#include "apr.h"
#include "apr_strings.h"
#include "apr_lock.h"
#define APR_WANT_STRFUNC
#include "apr_want.h"
#include "httpd.h"
#include "http_config.h"
#include "http_log.h"
#include "http_main.h"
#include "mpm.h"
#include "mpm_common.h"
#include "ap_mpm.h"
#include "ap_listen.h"
#include "mpm_default.h"
#define RESTART_CHAR '$'
#define GRACEFUL_CHAR '!'
#define AP_RESTART 0
#define AP_GRACEFUL 1
typedef struct ap_pod_t ap_pod_t;
struct ap_pod_t {
apr_file_t *pod_in;
apr_file_t *pod_out;
apr_pool_t *p;
apr_sockaddr_t *sa;
};
AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t *p, ap_pod_t **pod);
AP_DECLARE(int) ap_mpm_pod_check(ap_pod_t *pod);
AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t *pod);
AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t *pod, int graceful);
AP_DECLARE(void) ap_mpm_pod_killpg(ap_pod_t *pod, int num, int graceful);
RE: cvs commit: httpd-2.0/server/mpm/worker pod.c pod.h Makefile.in mpm.h worker.c
Posted by Ryan Bloom <rb...@covalent.net>.
> Modified: . CHANGES
> server/mpm/worker Makefile.in mpm.h worker.c
> Added: server/mpm/worker pod.c pod.h
> Log:
> Remove all signal handling from the worker MPM's child processes.
> Instead,
> we use the pipe of death for all communication between parent and
child.
I added the new pod.[ch] files so that other MPMs could continue to use
the current functions. Long-term, we probably want to combine the
functions.
Also, this was tested on Linux, so graceful seems to work.
Unfortunately, graceless doesn't work any better than it used to,
because Linux doesn't kill threads if the main thread in the process
dies. I know how to fix it, but it will require using pthread_cancel,
which we have always avoided in the past. I want to stress that this is
the same behavior we were getting before this change.
Tomorrow I will code the pthread_cancel stuff and post a patch for
review. I am assuming that using pthread_cancel will generate some
discussion. :-)
Ryan
RE: cvs commit: httpd-2.0/server/mpm/worker pod.c pod.h Makefile.in mpm.h worker.c
Posted by Ryan Bloom <rb...@covalent.net>.
> Modified: . CHANGES
> server/mpm/worker Makefile.in mpm.h worker.c
> Added: server/mpm/worker pod.c pod.h
> Log:
> Remove all signal handling from the worker MPM's child processes.
> Instead,
> we use the pipe of death for all communication between parent and
child.
I added the new pod.[ch] files so that other MPMs could continue to use
the current functions. Long-term, we probably want to combine the
functions.
Also, this was tested on Linux, so graceful seems to work.
Unfortunately, graceless doesn't work any better than it used to,
because Linux doesn't kill threads if the main thread in the process
dies. I know how to fix it, but it will require using pthread_cancel,
which we have always avoided in the past. I want to stress that this is
the same behavior we were getting before this change.
Tomorrow I will code the pthread_cancel stuff and post a patch for
review. I am assuming that using pthread_cancel will generate some
discussion. :-)
Ryan