A certain person complained over the phone again this a.m. about
having to tweak HARD_SERVER_LIMIT define for daedalus, and prefork MPM
is a simpler playground than worker for figuring out the user
interface (since there is no HARD_THREAD_LIMIT), so what the heck...
This adds a HardServerLimit directive to prefork which allows you to
set a really big* limit on MaxClients (if you can spare the shared
memory). As always, you get to play with MaxClients across restarts
but you can't play with HardServerLimit.
*what is really big? the admin should know what they're doing, but
just to catch obvious errors I put a limit of 20,000 on the value; if
that causes anybody problems I'd like an account on that machine :)
maybe we need to come up with a better magic number (99,999?)
We catch (and ignore) attempts to change HardServerLimit across
restarts, but for the life of me I don't know how to log an error in
that scenario. Log messages during restart config processing seem to
go to the bit bucket.
I could squirrel away the message and drop it in the log once I get to
ap_mpm_run() but that's pretty gross :(
I would not recommend putting HardServerLimit in the standard
configuration file. We should have a default HardServerLimit that
works for most folks, and the remaining few will get a warning
messages at startup telling them to look at the HardServerLimit
directive.
Index: server/mpm/prefork/prefork.c
===================================================================
RCS file: /home/cvs/httpd-2.0/server/mpm/prefork/prefork.c,v
retrieving revision 1.225
diff -u -r1.225 prefork.c
--- server/mpm/prefork/prefork.c 2001/12/18 13:48:53 1.225
+++ server/mpm/prefork/prefork.c 2001/12/18 16:08:58
@@ -114,10 +114,17 @@
* enough that we can read the whole thing without worrying too much about
* the overhead.
*/
-#ifndef HARD_SERVER_LIMIT
-#define HARD_SERVER_LIMIT 256
+#ifndef DEFAULT_HARD_SERVER_LIMIT
+#define DEFAULT_HARD_SERVER_LIMIT 256
#endif
+/* Admin can't tune HardServerLimit beyond HARD_SERVER_MAX. We want
+ * some sort of compile-time limit to help catch typos.
+ */
+#ifndef MAX_HARD_SERVER_LIMIT
+#define MAX_HARD_SERVER_LIMIT 20000
+#endif
+
#ifndef HARD_THREAD_LIMIT
#define HARD_THREAD_LIMIT 1
#endif
@@ -129,7 +136,9 @@
static int ap_daemons_to_start=0;
static int ap_daemons_min_free=0;
static int ap_daemons_max_free=0;
-static int ap_daemons_limit=0;
+static int ap_daemons_limit=0; /* MaxClients */
+static int hard_server_limit = DEFAULT_HARD_SERVER_LIMIT;
+static int first_hard_server_limit;
static ap_pod_t *pod;
@@ -319,7 +328,7 @@
*result = AP_MPMQ_DYNAMIC;
return APR_SUCCESS;
case AP_MPMQ_HARD_LIMIT_DAEMONS:
- *result = HARD_SERVER_LIMIT;
+ *result = hard_server_limit;
return APR_SUCCESS;
case AP_MPMQ_HARD_LIMIT_THREADS:
*result = HARD_THREAD_LIMIT;
@@ -966,7 +975,9 @@
pconf = _pconf;
ap_server_conf = s;
-
+
+ first_hard_server_limit = hard_server_limit;
+
if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
/* XXX: hey, what's the right way for the mpm to indicate a fatal error? */
ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ALERT, 0, s,
@@ -1212,7 +1223,7 @@
ap_daemons_to_start = DEFAULT_START_DAEMON;
ap_daemons_min_free = DEFAULT_MIN_FREE_DAEMON;
ap_daemons_max_free = DEFAULT_MAX_FREE_DAEMON;
- ap_daemons_limit = HARD_SERVER_LIMIT;
+ ap_daemons_limit = hard_server_limit;
ap_pid_fname = DEFAULT_PIDLOG;
ap_scoreboard_fname = DEFAULT_SCOREBOARD;
ap_lock_fname = DEFAULT_LOCKFILE;
@@ -1282,17 +1293,16 @@
}
ap_daemons_limit = atoi(arg);
- if (ap_daemons_limit > HARD_SERVER_LIMIT) {
+ if (ap_daemons_limit > hard_server_limit) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
- "WARNING: MaxClients of %d exceeds compile time limit "
- "of %d servers,", ap_daemons_limit, HARD_SERVER_LIMIT);
+ "WARNING: MaxClients of %d exceeds HardServerLimit value "
+ "of %d servers,", ap_daemons_limit, hard_server_limit);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
" lowering MaxClients to %d. To increase, please "
- "see the", HARD_SERVER_LIMIT);
+ "see the HardServerLimit", hard_server_limit);
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
- " HARD_SERVER_LIMIT define in %s.",
- AP_MPM_HARD_LIMITS_FILE);
- ap_daemons_limit = HARD_SERVER_LIMIT;
+ " directive.");
+ ap_daemons_limit = hard_server_limit;
}
else if (ap_daemons_limit < 1) {
ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
@@ -1302,6 +1312,42 @@
return NULL;
}
+static const char *set_hard_server_limit (cmd_parms *cmd, void *dummy, const char
+*arg)
+{
+ int tmp_hard_server_limit;
+
+ const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+ if (err != NULL) {
+ return err;
+ }
+
+ tmp_hard_server_limit = atoi(arg);
+ /* you cannot change HardServerLimit across a restart; ignore
+ * any such attempts
+ */
+ if (first_hard_server_limit &&
+ tmp_hard_server_limit != hard_server_limit) {
+ /* XXX how do we log a message? the error log is a bit bucket at this point
+*/
+ return NULL;
+ }
+ hard_server_limit = tmp_hard_server_limit;
+
+ if (hard_server_limit > MAX_HARD_SERVER_LIMIT) {
+ ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
+ "WARNING: HardServerLimit of %d exceeds compile time limit "
+ "of %d servers,", hard_server_limit, MAX_HARD_SERVER_LIMIT);
+ ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
+ " lowering HardServerLimit to %d.", MAX_HARD_SERVER_LIMIT);
+ hard_server_limit = MAX_HARD_SERVER_LIMIT;
+ }
+ else if (hard_server_limit < 1) {
+ ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
+ "WARNING: Require HardServerLimit > 0, setting to 1");
+ hard_server_limit = 1;
+ }
+ return NULL;
+}
+
static const command_rec prefork_cmds[] = {
UNIX_DAEMON_COMMANDS,
LISTEN_COMMANDS,
@@ -1313,6 +1359,8 @@
"Maximum number of idle children"),
AP_INIT_TAKE1("MaxClients", set_server_limit, NULL, RSRC_CONF,
"Maximum number of children alive at the same time"),
+AP_INIT_TAKE1("HardServerLimit", set_hard_server_limit, NULL, RSRC_CONF,
+ "Maximum value of MaxClients for this run of Apache"),
{ NULL }
};
--
Jeff Trawick | [EMAIL PROTECTED] | PGP public key at web site:
http://www.geocities.com/SiliconValley/Park/9289/
Born in Roswell... married an alien...
