Fix MaxClients in the Worker MPM, so that it specifies the maximum

number of clients that can connect at the same time, instead of
specifying the maximum number of child processes.
Submitted by:	Aaron Bannert <aaron@clove.org>

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@91122 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/CHANGES b/CHANGES
index 538fcece0ddae98663ce7bd5042a28d89bb5cfdf..43e10c34e3705ce514368084b4bb4d2e85fd3324 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,10 @@
 Changes with Apache 2.0.26-dev
 
+  *) Fix MaxClients in the Worker MPM, so that it specifies the maximum
+     number of clients that can connect at the same time, instead of
+     specifying the maximum number of child processes.
+     [Aaron Bannert <aaron@clove.org>]
+
   *) Switch proc_pthread AcceptMutex configuration directive to pthread to 
      be consistent with 1.3.  [Justin Erenkrantz]
 

diff --git a/server/mpm/worker/worker.c b/server/mpm/worker/worker.c
index e2acea5e7e3e7a5e0fffb83b786ac40b3baf34d3..2cd810d5d8d68804bf9907d0a095b013a3118635 100644 (file)
--- a/server/mpm/worker/worker.c
+++ b/server/mpm/worker/worker.c
@@ -1422,6 +1422,44 @@ static void worker_pre_config(apr_pool_t *pconf, apr_pool_t *plog, apr_pool_t *p
 {
     static int restart_num = 0;
     int no_detach, debug;
+    ap_directive_t *pdir;
+    ap_directive_t *max_clients = NULL;
+
+    /* make sure that "ThreadsPerChild" gets set before "MaxClients" */
+    for (pdir = ap_conftree; pdir != NULL; pdir = pdir->next) {
+        if (strncasecmp(pdir->directive, "ThreadsPerChild", 15) == 0) {
+            if (!max_clients) {
+                break; /* we're in the clear, got ThreadsPerChild first */
+            }
+            else {
+                /* now to swap the data */
+                ap_directive_t temp;
+
+                temp.directive = pdir->directive;
+                temp.args = pdir->args;
+                /* Make sure you don't change 'next', or you may get loops! */
+                /* XXX: first_child, parent, and data can never be set
+                 * for these directives, right? -aaron */
+                temp.filename = pdir->filename;
+                temp.line_num = pdir->line_num;
+
+                pdir->directive = max_clients->directive;
+                pdir->args = max_clients->args;
+                pdir->filename = max_clients->filename;
+                pdir->line_num = max_clients->line_num;
+                
+                max_clients->directive = temp.directive;
+                max_clients->args = temp.args;
+                max_clients->filename = temp.filename;
+                max_clients->line_num = temp.line_num;
+                break;
+            }
+        }
+        else if (!max_clients
+                && strncasecmp(pdir->directive, "MaxClients", 10) == 0) {
+            max_clients = pdir;
+        }
+    }
 
     debug = ap_exists_config_define("DEBUG");
 
@@ -1515,21 +1553,52 @@ static const char *set_max_spare_threads(cmd_parms *cmd, void *dummy,
 static const char *set_server_limit (cmd_parms *cmd, void *dummy,
                                     const char *arg) 
 {
+    int max_clients;
     const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
     if (err != NULL) {
         return err;
     }
 
-    ap_daemons_limit = atoi(arg);
+    /* It is ok to use ap_threads_per_child here because we are
+     * sure that it gets set before MaxClients in the pre_config stage. */
+    max_clients = atoi(arg);
+    if (max_clients < ap_threads_per_child) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
+                    "WARNING: MaxClients (%d) must be at least as large",
+                    max_clients);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
+                    " large as ThreadsPerChild (%d). Automatically",
+                    ap_threads_per_child);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
+                    " increasing MaxClients to %d.",
+                    ap_threads_per_child);
+       max_clients = ap_threads_per_child;
+    }
+    ap_daemons_limit = max_clients / ap_threads_per_child;
+    if ((max_clients > 0) && (max_clients % ap_threads_per_child)) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
+                    "WARNING: MaxClients (%d) is not an integer multiple",
+                    max_clients);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
+                    " of ThreadsPerChild (%d), lowering MaxClients to %d",
+                    ap_threads_per_child,
+                    ap_daemons_limit * ap_threads_per_child);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
+                    " for a maximum of %d child processes,",
+                    ap_daemons_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 would require %d servers,",
+                    max_clients, ap_daemons_limit);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
+                    " and would exceed the compile time limit of %d.",
+                    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);
+                    " Automatically lowering MaxClients to %d.  To increase,",
+                    HARD_SERVER_LIMIT);
        ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
-                    " HARD_SERVER_LIMIT define in %s.",
+                    " please see the HARD_SERVER_LIMIT define in %s.",
                     AP_MPM_HARD_LIMITS_FILE);
        ap_daemons_limit = HARD_SERVER_LIMIT;
     }