From b53ab4e9ad895f1fe0830cd153482693a2b18af2 Mon Sep 17 00:00:00 2001
From: Matthias Radestock <matthias@lshift.net>
Date: Thu, 8 Jan 2009 22:53:14 +0000
Subject: replace gen_server:cast with gen_server2:cast in rabbit_limiter The
 limiter is co-located with channels but interacts with queues which may be on
 different nodes. It is therefore subject to the message reordering problem of
 cross-node gen_server:cast - see bug 19749.

For consistency I replaced gen_server:call as well, though I left the
gen_server:start_link alone in order to avoid the (admittedly small)
penalty introduced by gen_server2's modified main loop.
---
 src/rabbit_limiter.erl | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/rabbit_limiter.erl b/src/rabbit_limiter.erl
index 3776edd0..e1d92f72 100644
--- a/src/rabbit_limiter.erl
+++ b/src/rabbit_limiter.erl
@@ -31,7 +31,7 @@
 
 -module(rabbit_limiter).
 
--behaviour(gen_server).
+-behaviour(gen_server2).
 
 -export([init/1, terminate/2, code_change/3, handle_call/3, handle_cast/2,
          handle_info/2]).
@@ -70,12 +70,12 @@ start_link(ChPid) ->
 shutdown(undefined) ->
     ok;
 shutdown(LimiterPid) ->
-    gen_server:cast(LimiterPid, shutdown).
+    gen_server2:cast(LimiterPid, shutdown).
 
 limit(undefined, 0) ->
     ok;
 limit(LimiterPid, PrefetchCount) ->
-    gen_server:cast(LimiterPid, {limit, PrefetchCount}).
+    gen_server2:cast(LimiterPid, {limit, PrefetchCount}).
 
 %% Ask the limiter whether the queue can deliver a message without
 %% breaching a limit
@@ -84,18 +84,18 @@ can_send(undefined, _QPid) ->
 can_send(LimiterPid, QPid) ->
     rabbit_misc:with_exit_handler(
       fun () -> true end,
-      fun () -> gen_server:call(LimiterPid, {can_send, QPid}) end).
+      fun () -> gen_server2:call(LimiterPid, {can_send, QPid}) end).
 
 %% Let the limiter know that the channel has received some acks from a
 %% consumer
 ack(undefined, _Count) -> ok;
-ack(LimiterPid, Count) -> gen_server:cast(LimiterPid, {ack, Count}).
+ack(LimiterPid, Count) -> gen_server2:cast(LimiterPid, {ack, Count}).
 
 register(undefined, _QPid) -> ok;
-register(LimiterPid, QPid) -> gen_server:cast(LimiterPid, {register, QPid}).
+register(LimiterPid, QPid) -> gen_server2:cast(LimiterPid, {register, QPid}).
 
 unregister(undefined, _QPid) -> ok;
-unregister(LimiterPid, QPid) -> gen_server:cast(LimiterPid, {unregister, QPid}).
+unregister(LimiterPid, QPid) -> gen_server2:cast(LimiterPid, {unregister, QPid}).
 
 %%----------------------------------------------------------------------------
 %% gen_server callbacks
-- 
cgit v1.2.1


From fbd08ac50a6418da6dc6ec04e048e9bcfd25378e Mon Sep 17 00:00:00 2001
From: Matthias Radestock <matthias@lshift.net>
Date: Thu, 8 Jan 2009 22:57:02 +0000
Subject: oops, meant to advertise this as an ordinary gen_server which it
 still is, since I left the gen_server:start_link in place.

---
 src/rabbit_limiter.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/rabbit_limiter.erl b/src/rabbit_limiter.erl
index e1d92f72..7ecdb6fb 100644
--- a/src/rabbit_limiter.erl
+++ b/src/rabbit_limiter.erl
@@ -31,7 +31,7 @@
 
 -module(rabbit_limiter).
 
--behaviour(gen_server2).
+-behaviour(gen_server).
 
 -export([init/1, terminate/2, code_change/3, handle_call/3, handle_cast/2,
          handle_info/2]).
-- 
cgit v1.2.1