drag in code from bug21966

since we need the ability to find all channels

2 files changed, 27 insertions, 13 deletions

diff --git a/docs/rabbitmqctl.1.pod b/docs/rabbitmqctl.1.pod
index c4d1b784..b82d5b87 100644
--- a/docs/rabbitmqctl.1.pod
+++ b/docs/rabbitmqctl.1.pod
@@ -284,7 +284,7 @@ separated by tab characters.
 
 =item list_connections [I<connectioninfoitem> ...]
 
-List queue information by virtual host. Each line printed describes an
+List current AMQP connections. Each line printed describes a
 connection, with the requested I<connectioninfoitem> values separated
 by tab characters.  If no I<connectioninfoitem>s are specified then
 I<user>, I<peer_address>, I<peer_port> and I<state> are assumed.
@@ -295,7 +295,7 @@ I<user>, I<peer_address>, I<peer_port> and I<state> are assumed.
 
 =over
 
-=item node
+=item pid
 
 id of the Erlang process associated with the connection
 
diff --git a/src/vm_memory_monitor.erl b/src/vm_memory_monitor.erl
index 91788caa..02bd0499 100644
--- a/src/vm_memory_monitor.erl
+++ b/src/vm_memory_monitor.erl
@@ -37,8 +37,6 @@
 %%
 %% This module tries to warn Rabbit before such situations occur, so
 %% that it has a higher chance to avoid running out of memory.
-%%
-%% This code depends on Erlang os_mon application.
 
 -module(vm_memory_monitor).
 
@@ -78,6 +76,7 @@
              ('ignore' | {'error', any()} | {'ok', pid()})).
 -spec(update/0 :: () -> 'ok').
 -spec(get_total_memory/0 :: () -> (non_neg_integer() | 'unknown')).
+-spec(get_vm_limit/0 :: () -> (non_neg_integer() | 'unknown')).
 -spec(get_memory_limit/0 :: () -> (non_neg_integer() | 'undefined')).
 -spec(get_check_interval/0 :: () -> non_neg_integer()).
 -spec(set_check_interval/1 :: (non_neg_integer()) -> 'ok').
@@ -97,6 +96,9 @@ update() ->
 get_total_memory() ->
     get_total_memory(os:type()).
 
+get_vm_limit() ->
+    get_vm_limit(os:type()).
+
 get_check_interval() ->
     gen_server:call(?MODULE, get_check_interval, infinity).
 
@@ -208,17 +210,26 @@ start_timer(Timeout) ->
     {ok, TRef} = timer:apply_interval(Timeout, ?MODULE, update, []),
     TRef.
 
+%% According to http://msdn.microsoft.com/en-us/library/aa366778(VS.85).aspx
+%% Windows has 2GB and 8TB of address space for 32 and 64 bit accordingly.
+get_vm_limit({win32,_OSname}) ->
+    case erlang:system_info(wordsize) of
+        4 -> 2*1024*1024*1024;          %% 2 GB for 32 bits  2^31
+        8 -> 8*1024*1024*1024*1024      %% 8 TB for 64 bits  2^42
+    end;
+
 %% On a 32-bit machine, if you're using more than 2 gigs of RAM you're
 %% in big trouble anyway.
-get_vm_limit() ->
+get_vm_limit(_OsType) ->
     case erlang:system_info(wordsize) of
-        4 -> 4294967296;     %% 4 GB for 32 bits  2^32
-        8 -> 281474976710656 %% 256 TB for 64 bits 2^48
+        4 -> 4*1024*1024*1024;          %% 4 GB for 32 bits  2^32
+        8 -> 256*1024*1024*1024*1024    %% 256 TB for 64 bits 2^48
              %%http://en.wikipedia.org/wiki/X86-64#Virtual_address_space_details
     end.
 
 get_mem_limit(MemFraction, TotalMemory) ->
-    lists:min([trunc(TotalMemory * MemFraction), get_vm_limit()]).
+    AvMem = lists:min([TotalMemory, get_vm_limit()]),
+    trunc(AvMem * MemFraction).
 
 %%----------------------------------------------------------------------------
 %% Internal Helpers
@@ -250,11 +261,14 @@ get_total_memory({unix,freebsd}) ->
     PageCount * PageSize;
 
 get_total_memory({win32,_OSname}) ->
-    [Result|_] = os_mon_sysinfo:get_mem_info(),
-    {ok, [_MemLoad, TotPhys, _AvailPhys,
-          _TotPage, _AvailPage, _TotV, _AvailV], _RestStr} =
-        io_lib:fread("~d~d~d~d~d~d~d", Result),
-    TotPhys;
+    %% Due to the Erlang print format bug, on Windows boxes the memory size is
+    %% broken. For example Windows 7 64 bit with 4Gigs of RAM we get negative
+    %% memory size:
+    %% > os_mon_sysinfo:get_mem_info().
+    %% ["76 -1658880 1016913920 -1 -1021628416 2147352576 2134794240\n"]
+    %% Due to this bug, we don't actually know anything. Even if the number is
+    %% postive we can't be sure if it's correct.
+    unknown;
 
 get_total_memory({unix, linux}) ->
     File = read_proc_file("/proc/meminfo"),