From 9d929da847c44c1f37a3b8c773aeed63c46fd4f8 Mon Sep 17 00:00:00 2001 From: Simon MacMullen Date: Thu, 29 May 2014 12:13:27 +0100 Subject: Don't prioritise DOWNs from the left. Also explain why we prioritise in various ways. --- src/gm.erl | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/src/gm.erl b/src/gm.erl index fb59b9cb..7a2f5835 100644 --- a/src/gm.erl +++ b/src/gm.erl @@ -732,8 +732,21 @@ code_change(_OldVsn, State, _Extra) -> prioritise_info(flush, _Len, _State) -> 1; +%% DOWN messages should not overtake initial catchups; if they do we +%% will receive a DOWN we do not know what to do with. prioritise_info({'DOWN', _MRef, process, _Pid, _Reason}, _Len, - #state { members_state = MS }) when MS /= undefined -> + #state { members_state = undefined }) -> + 0; +%% We should not prioritise DOWN messages from our left since +%% otherwise the DOWN can overtake any last activity from the left, +%% causing that activity to be lost. +prioritise_info({'DOWN', _MRef, process, LeftPid, _Reason}, _Len, + #state { left = {{_LeftVer, LeftPid}, _MRef2} }) -> + 0; +%% But prioritise all other DOWNs - we want to make sure we are not +%% sending activity into the void for too long because our right is +%% down but we don't know it. +prioritise_info({'DOWN', MRef, process, Pid, _Reason}, _Len, _State) -> 1; prioritise_info(_, _Len, _State) -> 0. -- cgit v1.2.1