From 2056d06cae4937c12433d1247b02c346625f86a4 Mon Sep 17 00:00:00 2001
From: Simo Sorce <idra@samba.org>
Date: Thu, 5 May 2011 17:56:31 -0400
Subject: s3-prefork: add way to manage number of clients per child

The allowed_clients var is a parent managed variable that tell children how
many clients they are allowed to handle at the same time. This way children
can overcommit but within parent controlled limits.

Signed-off-by: Andreas Schneider <asn@samba.org>
---
 source3/lib/server_prefork.c | 35 +++++++++++++++++++++++++++++++++--
 source3/lib/server_prefork.h |  6 +++++-
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/source3/lib/server_prefork.c b/source3/lib/server_prefork.c
index b337fa0c3b..0a8199a6ea 100644
--- a/source3/lib/server_prefork.c
+++ b/source3/lib/server_prefork.c
@@ -36,6 +36,8 @@ struct prefork_pool {
 
 	int pool_size;
 	struct pf_worker_data *pool;
+
+	int allowed_clients;
 };
 
 int prefork_pool_destructor(struct prefork_pool *pfp)
@@ -86,6 +88,10 @@ bool prefork_create_pool(struct tevent_context *ev_ctx,
 	talloc_set_destructor(pfp, prefork_pool_destructor);
 
 	for (i = 0; i < min_children; i++) {
+
+		pfp->pool[i].allowed_clients = 1;
+		pfp->pool[i].started = now;
+
 		pid = sys_fork();
 		switch (pid) {
 		case -1:
@@ -102,7 +108,6 @@ bool prefork_create_pool(struct tevent_context *ev_ctx,
 
 		default: /* THE PARENT */
 			pfp->pool[i].pid = pid;
-			pfp->pool[i].started = now;
 			break;
 		}
 	}
@@ -126,6 +131,9 @@ int prefork_add_children(struct tevent_context *ev_ctx,
 			continue;
 		}
 
+		pfp->pool[i].allowed_clients = 1;
+		pfp->pool[i].started = now;
+
 		pid = sys_fork();
 		switch (pid) {
 		case -1:
@@ -144,7 +152,6 @@ int prefork_add_children(struct tevent_context *ev_ctx,
 
 		default: /* THE PARENT */
 			pfp->pool[i].pid = pid;
-			pfp->pool[i].started = now;
 			j++;
 			break;
 		}
@@ -263,6 +270,30 @@ bool prefork_mark_pid_dead(struct prefork_pool *pfp, pid_t pid)
 	return false;
 }
 
+void prefork_increase_allowed_clients(struct prefork_pool *pfp, int max)
+{
+	int i;
+
+	for (i = 0; i < pfp->pool_size; i++) {
+		if (pfp->pool[i].status == PF_WORKER_NONE) {
+			continue;
+		}
+
+		if (pfp->pool[i].allowed_clients < max) {
+			pfp->pool[i].allowed_clients++;
+		}
+	}
+}
+
+void prefork_reset_allowed_clients(struct prefork_pool *pfp)
+{
+	int i;
+
+	for (i = 0; i < pfp->pool_size; i++) {
+		pfp->pool[i].allowed_clients = 1;
+	}
+}
+
 /* ==== Functions used by children ==== */
 
 static SIG_ATOMIC_T pf_alarm;
diff --git a/source3/lib/server_prefork.h b/source3/lib/server_prefork.h
index 7e95602e81..bf9f3d3fe7 100644
--- a/source3/lib/server_prefork.h
+++ b/source3/lib/server_prefork.h
@@ -37,10 +37,12 @@ enum pf_server_cmds {
 struct pf_worker_data {
 	pid_t pid;
 	enum pf_worker_status status;
-	enum pf_server_cmds cmds;
 	time_t started;
 	time_t last_used;
 	int num_clients;
+
+	enum pf_server_cmds cmds;
+	int allowed_clients;
 };
 
 typedef int (prefork_main_fn_t)(struct tevent_context *ev,
@@ -67,6 +69,8 @@ int prefork_retire_children(struct prefork_pool *pfp,
 			    int num_children, time_t age_limit);
 int prefork_count_active_children(struct prefork_pool *pfp, int *total);
 bool prefork_mark_pid_dead(struct prefork_pool *pfp, pid_t pid);
+void prefork_increase_allowed_clients(struct prefork_pool *pfp, int max);
+void prefork_reset_allowed_clients(struct prefork_pool *pfp);
 
 /* ==== Functions used by children ==== */
 
-- 
cgit