s3-spoolss: Introduce helper function to manage pool.

We were not properly managing allowed clients and pool management was
duplicated across a few callers.
Concentrate all management heuristics in one single function.

Signed-off-by: Andreas Schneider <asn@samba.org>
Signed-off-by: Simo Sorce <idra@samba.org>

diff --git a/source3/printing/spoolssd.c b/source3/printing/spoolssd.c
index bc4065c04e43cc1395376afcf405d69555d6f7a9..2cbd6e3603c77b9d32ccbf6e1b45a4e7bf140b7e 100644 (file)
--- a/source3/printing/spoolssd.c
+++ b/source3/printing/spoolssd.c
@@ -56,6 +56,8 @@ static int spoolss_child_id = 0;
 
 pid_t start_spoolssd(struct tevent_context *ev_ctx,
                     struct messaging_context *msg_ctx);
+static void spoolss_manage_pool(struct tevent_context *ev_ctx,
+                               struct messaging_context *msg_ctx);
 
 static void spoolss_prefork_config(void)
 {
@@ -75,13 +77,13 @@ static void spoolss_prefork_config(void)
        }
 
        prefork_str = lp_parm_const_string(GLOBAL_SECTION_SNUM,
-                                          "spoolssd", "prefork", "none");
+                                          "spoolss", "prefork", "none");
        if (strcmp(prefork_str, "none") == 0) {
                use_defaults = true;
        } else {
                ret = sscanf(prefork_str, "%d:%d:%d", &min, &max, &rate);
                if (ret != 3) {
-                       DEBUG(0, ("invalid format for spoolssd:prefork!\n"));
+                       DEBUG(0, ("invalid format for spoolss:prefork!\n"));
                        use_defaults = true;
                }
        }
@@ -153,6 +155,7 @@ static void update_conf(struct tevent_context *ev,
        spoolss_reopen_logs(spoolss_child_id);
        if (spoolss_child_id == 0) {
                spoolss_prefork_config();
+               spoolss_manage_pool(ev, msg);
        }
 }
 
@@ -585,6 +588,58 @@ static void check_updater_child(void)
        }
 }
 
+static void spoolss_manage_pool(struct tevent_context *ev_ctx,
+                               struct messaging_context *msg_ctx)
+{
+       time_t now = time(NULL);
+       int active, total;
+       int ret, n;
+
+       if ((spoolss_prefork_status & SPOOLSS_NEW_MAX) &&
+           !(spoolss_prefork_status & SPOLLSS_ENOSPC)) {
+               ret = prefork_expand_pool(spoolss_pool, spoolss_max_children);
+               if (ret == ENOSPC) {
+                       spoolss_prefork_status |= SPOLLSS_ENOSPC;
+               }
+               spoolss_prefork_status &= ~SPOOLSS_NEW_MAX;
+       }
+
+       active = prefork_count_active_children(spoolss_pool, &total);
+
+       if ((total < spoolss_max_children) &&
+           ((total < spoolss_min_children) ||
+            (total - active < spoolss_spawn_rate))) {
+               n = prefork_add_children(ev_ctx, msg_ctx,
+                                        spoolss_pool, spoolss_spawn_rate);
+               if (n < spoolss_spawn_rate) {
+                       DEBUG(10, ("Tried to start %d children but only,"
+                                  "%d were actually started.!\n",
+                                  spoolss_spawn_rate, n));
+               }
+       }
+
+       if (total - active > spoolss_min_children) {
+               if ((total - spoolss_min_children) >= spoolss_spawn_rate) {
+                       prefork_retire_children(spoolss_pool,
+                                               spoolss_spawn_rate,
+                                               now - SPOOLSS_MIN_LIFE);
+               }
+       }
+
+       n = prefork_count_allowed_connections(spoolss_pool);
+       if (n <= spoolss_spawn_rate) {
+               do {
+                       prefork_increase_allowed_clients(spoolss_pool);
+                       n = prefork_count_allowed_connections(spoolss_pool);
+               } while (n <= spoolss_spawn_rate);
+       } else if (n > spoolss_max_children + spoolss_spawn_rate) {
+               do {
+                       prefork_decrease_allowed_clients(spoolss_pool);
+                       n = prefork_count_allowed_connections(spoolss_pool);
+               } while (n > spoolss_max_children + spoolss_spawn_rate);
+       }
+}
+
 static bool spoolssd_schedule_check(struct tevent_context *ev_ctx,
                                    struct messaging_context *msg_ctx,
                                    struct timeval current_time);
@@ -598,28 +653,12 @@ static void spoolssd_sigchld_handler(struct tevent_context *ev_ctx,
                                     void *pvt)
 {
        struct messaging_context *msg_ctx;
-       int active, total;
-       int n, r;
 
        msg_ctx = talloc_get_type_abort(pvt, struct messaging_context);
 
-       /* now check we do not descend below the minimum */
-       active = prefork_count_active_children(pfp, &total);
-
-       n = 0;
-       if (total < spoolss_min_children) {
-               n = total - spoolss_min_children;
-       } else if (total - active < (total / 4)) {
-               n = spoolss_min_children;
-       }
-
-       if (n > 0) {
-               r = prefork_add_children(ev_ctx, msg_ctx, pfp, n);
-               if (r < n) {
-                       DEBUG(10, ("Tried to start %d children but only,"
-                                  "%d were actually started.!\n", n, r));
-               }
-       }
+       /* run pool management so we can fork/retire or increase
+        * the allowed connections per child based on load */
+       spoolss_manage_pool(ev_ctx, msg_ctx);
 
        /* also check if the updater child is alive and well */
        check_updater_child();
@@ -667,41 +706,12 @@ static void spoolssd_check_children(struct tevent_context *ev_ctx,
                                    void *pvt)
 {
        struct messaging_context *msg_ctx;
-       time_t now = time(NULL);
-       int active, total;
-       int ret, n;
 
        msg_ctx = talloc_get_type_abort(pvt, struct messaging_context);
 
-       if ((spoolss_prefork_status & SPOOLSS_NEW_MAX) &&
-           !(spoolss_prefork_status & SPOLLSS_ENOSPC)) {
-               ret = prefork_expand_pool(spoolss_pool, spoolss_max_children);
-               if (ret == ENOSPC) {
-                       spoolss_prefork_status |= SPOLLSS_ENOSPC;
-               }
-               spoolss_prefork_status &= ~SPOOLSS_NEW_MAX;
-       }
-
-       active = prefork_count_active_children(spoolss_pool, &total);
+       spoolss_manage_pool(ev_ctx, msg_ctx);
 
-       if (total - active < spoolss_spawn_rate) {
-               n = prefork_add_children(ev_ctx, msg_ctx,
-                                        spoolss_pool, spoolss_spawn_rate);
-               if (n < spoolss_spawn_rate) {
-                       DEBUG(10, ("Tried to start 5 children but only,"
-                                  "%d were actually started.!\n", n));
-               }
-       }
-
-       if (total - active > spoolss_min_children) {
-               if ((total - spoolss_min_children) >= spoolss_spawn_rate) {
-                       prefork_retire_children(spoolss_pool,
-                                               spoolss_spawn_rate,
-                                               now - SPOOLSS_MIN_LIFE);
-               }
-       }
-
-       ret = spoolssd_schedule_check(ev_ctx, msg_ctx, current_time);
+       spoolssd_schedule_check(ev_ctx, msg_ctx, current_time);
 }
 
 static void print_queue_forward(struct messaging_context *msg,
@@ -906,6 +916,8 @@ pid_t start_spoolssd(struct tevent_context *ev_ctx,
 
        DEBUG(1, ("SPOOLSS Daemon Started (%d)\n", getpid()));
 
+       spoolss_manage_pool(ev_ctx, msg_ctx);
+
        /* loop forever */
        ret = tevent_loop_wait(ev_ctx);