From e85485154d5df36041c185a8540f3c09a98f5937 Mon Sep 17 00:00:00 2001
From: Art Cancro <ajc@citadel.org>
Date: Mon, 12 Jul 2010 17:16:45 +0000
Subject: [PATCH] * Improved the thread pool logic so that we don't end up
 creating dozens of extra worker threads during shutdown

---
 webcit/context_loop.c | 17 +++++++++++++----
 webcit/sysdep.c       |  4 ++--
 webcit/webcit.h       |  2 ++
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/webcit/context_loop.c b/webcit/context_loop.c
index 7521207b2..8559f09b0 100644
--- a/webcit/context_loop.c
+++ b/webcit/context_loop.c
@@ -106,15 +106,24 @@ void do_housekeeping(void)
 		session_destroy_modules(&sessions_to_kill);
 		sessions_to_kill = sptr;
 	}
+}
 
-	/*
-	 * Check the size of our thread pool.  If all threads are executing, spawn another.
-	 */
-	begin_critical_section(S_SPAWNER);
+/*
+ * Check the size of our thread pool.  If all threads are executing, spawn another.
+ */
+void check_thread_pool_size(void)
+{
+	if (time_to_die) return;		/* don't expand the thread pool during shutdown */
+
+	begin_critical_section(S_SPAWNER);	/* only one of these should run at a time */
 	while (
 		(num_threads_executing >= num_threads_existing)
 		&& (num_threads_existing < MAX_WORKER_THREADS)
 	) {
+		lprintf(3, "%d of %d threads are executing.  Adding another worker thread.\n",
+			num_threads_executing,
+			num_threads_existing
+		);
 		spawn_another_worker_thread();
 	}
 	end_critical_section(S_SPAWNER);
diff --git a/webcit/sysdep.c b/webcit/sysdep.c
index fbe16ca0a..b3470a042 100644
--- a/webcit/sysdep.c
+++ b/webcit/sysdep.c
@@ -204,6 +204,8 @@ void worker_entry(void)
 		}
 		if (ssock < 0 ) continue;
 
+		check_thread_pool_size();
+
 		/* Now do something. */
 		if (msock < 0) {
 			if (ssock > 0) close (ssock);
@@ -429,8 +431,6 @@ void spawn_another_worker_thread()
 	pthread_attr_t attr;	/* Thread attributes */
 	int ret;
 
-	lprintf(3, "Creating a new thread.\n");
-
 	++num_threads_existing;
 	++num_threads_executing;
 
diff --git a/webcit/webcit.h b/webcit/webcit.h
index 2f1e04873..1d632d476 100644
--- a/webcit/webcit.h
+++ b/webcit/webcit.h
@@ -822,6 +822,7 @@ void sleeeeeeeeeep(int);
 void http_transmit_thing(const char *content_type, int is_static);
 long unescape_input(char *buf);
 void do_selected_iconbar(void);
+void check_thread_pool_size(void);
 void spawn_another_worker_thread(void);
 void StrEndTab(StrBuf *Target, int tabnum, int num_tabs);
 void StrBeginTab(StrBuf *Target, int tabnum, int num_tabs);
@@ -899,3 +900,4 @@ void http_datestring(char *buf, size_t n, time_t xtime);
 #define WC_TIMEFORMAT_AMPM 1
 #define WC_TIMEFORMAT_24 2
 
+extern int time_to_die;			/* Nonzero if server is shutting down */
-- 
2.30.2