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Date: 24 Mar 2004 20:28:49 -0000
Message-ID: <20040324202849.14225.qmail@minotaur.apache.org>
From: geoff@apache.org
To: httpd-2.0-cvs@apache.org
Subject: cvs commit: httpd-2.0/server/mpm/winnt child.c

geoff       2004/03/24 12:28:49

  Modified:    .        Tag: APACHE_2_0_BRANCH CHANGES
               server/mpm/winnt Tag: APACHE_2_0_BRANCH child.c
  Log:
  Tweak worker thread accounting routines to eliminate
  server hang when number of Listen directives in httpd.conf
  is greater than or equal to the setting of ThreadsPerChild.
  Reviewed by:	 stoddard, trawick, geoff
  
  Revision  Changes    Path
  No                   revision
  No                   revision
  1.988.2.258 +5 -0      httpd-2.0/CHANGES
  
  Index: CHANGES
  ===================================================================
  RCS file: /home/cvs/httpd-2.0/CHANGES,v
  retrieving revision 1.988.2.257
  retrieving revision 1.988.2.258
  diff -u -r1.988.2.257 -r1.988.2.258
  --- CHANGES	18 Mar 2004 08:50:44 -0000	1.988.2.257
  +++ CHANGES	24 Mar 2004 20:28:48 -0000	1.988.2.258
  @@ -2,6 +2,11 @@
   
   Changes with Apache 2.0.49
   
  +  *) Win32: Tweak worker thread accounting routines to eliminate
  +     server hang when number of Listen directives in httpd.conf
  +     is greater than or equal to the setting of ThreadsPerChild.
  +     [Bill Stoddard]
  +
     *) SECURITY: CAN-2004-0174 (cve.mitre.org)
        Fix starvation issue on listening sockets where a short-lived
        connection on a rarely-accessed listening socket will cause a
  
  
  
  No                   revision
  No                   revision
  1.9.2.15  +21 -4     httpd-2.0/server/mpm/winnt/child.c
  
  Index: child.c
  ===================================================================
  RCS file: /home/cvs/httpd-2.0/server/mpm/winnt/child.c,v
  retrieving revision 1.9.2.14
  retrieving revision 1.9.2.15
  diff -u -r1.9.2.14 -r1.9.2.15
  --- child.c	8 Mar 2004 23:33:03 -0000	1.9.2.14
  +++ child.c	24 Mar 2004 20:28:49 -0000	1.9.2.15
  @@ -63,6 +63,7 @@
   static PCOMP_CONTEXT qhead = NULL;
   static PCOMP_CONTEXT qtail = NULL;
   static int num_completion_contexts = 0;
  +static int max_num_completion_contexts = 0;
   static HANDLE ThreadDispatchIOCP = NULL;
   static HANDLE qwait_event = NULL;
   
  @@ -111,11 +112,12 @@
           apr_thread_mutex_unlock(qlock);
     
           if (!context) {
  -            /* We failed to grab a context off the queue, consider allocating a
  -             * new one out of the child pool. There may be up to ap_threads_per_child
  -             * contexts in the system at once.
  +            /* We failed to grab a context off the queue, consider allocating
  +             * a new one out of the child pool. There may be up to 
  +             * (ap_threads_per_child + num_listeners) contexts in the system 
  +             * at once.
                */
  -            if (num_completion_contexts >= ap_threads_per_child) {
  +            if (num_completion_contexts >= max_num_completion_contexts) {
                   /* All workers are busy, need to wait for one */
                   static int reported = 0;
                   if (!reported) {
  @@ -766,6 +768,7 @@
   static void create_listener_thread()
   {
       int tid;
  +    int num_listeners = 0;
       if (!use_acceptex) {
           _beginthreadex(NULL, 0, (LPTHREAD_START_ROUTINE) win9x_accept,
                          NULL, 0, &tid);
  @@ -774,6 +777,20 @@
            * XXX: Why would we have a NULL sd in our listeners?
            */
           ap_listen_rec *lr;
  +
  +        /* Number of completion_contexts allowed in the system is
  +         * (ap_threads_per_child + num_listeners). We need the additional
  +         * completion contexts to prevent server hangs when ThreadsPerChild
  +         * is configured to something less than or equal to the number
  +         * of listeners. This is not a usual case, but people have 
  +         * encountered it.
  +         * */
  +        for (lr = ap_listeners; lr ; lr = lr->next) {
  +            num_listeners++;
  +        }
  +        max_num_completion_contexts = ap_threads_per_child + num_listeners;
  +
  +        /* Now start a thread per listener */
           for (lr = ap_listeners; lr; lr = lr->next) {
               if (lr->sd != NULL) {
                   _beginthreadex(NULL, 1000, (LPTHREAD_START_ROUTINE) winnt_accept,