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authorRickard Green <[email protected]>2013-10-02 10:07:27 +0200
committerRickard Green <[email protected]>2013-11-18 20:12:35 +0100
commitca0425c6ff85262bc15367f5fd9cbc51cde52b20 (patch)
tree0002e42905b936ccd5f2ba57d9a25819eef2cdb8 /erts/preloaded/src/erts_internal.erl
parent20641fe0f2ea745873fc7557448d3a7deb1bd639 (diff)
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Execution of system tasks in context of another process
A process requesting a system task to be executed in the context of another process will be notified by a message when the task has executed. This message will be on the form: {RequestType, RequestId, Pid, Result}. A process requesting a system task to be executed can set priority on the system task. The requester typically set the same priority on the task as its own process priority, and by this avoiding priority inversion. A request for execution of a system task is made by calling the statically linked in NIF erts_internal:request_system_task(Pid, Prio, Request). This is an undocumented ERTS internal function that should remain so. It should *only* be called from BIF implementations. Currently defined system tasks are: * garbage_collect * check_process_code Further system tasks can and will be implemented in the future. The erlang:garbage_collect/[1,2] and erlang:check_process_code/[2,3] BIFs are now implemented using system tasks. Both the 'garbage_collect' and the 'check_process_code' operations perform or may perform garbage_collections. By doing these via the system task functionality all garbage collect operations in the system will be performed solely in the context of the process being garbage collected. This makes it possible to later implement functionality for disabling garbage collection of a process over context switches. Newly introduced BIFs: * erlang:garbage_collect/2 - The new second argument is an option list. Introduced option: * {async, RequestId} - making it possible for users to issue asynchronous garbage collect requests. * erlang:check_process_code/3 - The new third argument is an option list. Introduced options: * {async, RequestId} - making it possible for users to issue asynchronous check process code requests. * {allow_gc, boolean()} - making it possible to issue requests that aren't allowed to garbage collect (operation will abort if gc should be needed). These options have been introduced as a preparation for parallelization of check_process_code operations when the code_server is about to purge a module.
Diffstat (limited to 'erts/preloaded/src/erts_internal.erl')
-rw-r--r--erts/preloaded/src/erts_internal.erl21
1 files changed, 21 insertions, 0 deletions
diff --git a/erts/preloaded/src/erts_internal.erl b/erts/preloaded/src/erts_internal.erl
index 8a8cd52d64..c8e8e7e069 100644
--- a/erts/preloaded/src/erts_internal.erl
+++ b/erts/preloaded/src/erts_internal.erl
@@ -33,6 +33,10 @@
-export([port_command/3, port_connect/2, port_close/1,
port_control/3, port_call/3, port_info/1, port_info/2]).
+-export([request_system_task/3]).
+
+-export([check_process_code/2]).
+
%%
%% Await result of send to port
%%
@@ -139,3 +143,20 @@ port_info(_Result) ->
port_info(_Result, _Item) ->
erlang:nif_error(undefined).
+
+-spec request_system_task(Pid, Prio, Request) -> 'ok' when
+ Prio :: 'max' | 'high' | 'normal' | 'low',
+ Request :: {'garbage_collect', term()}
+ | {'check_process_code', term(), module(), boolean()},
+ Pid :: pid().
+
+request_system_task(_Pid, _Prio, _Request) ->
+ erlang:nif_error(undefined).
+
+-spec check_process_code(Module, OptionList) -> boolean() when
+ Module :: module(),
+ Option :: {allow_gc, boolean()},
+ OptionList :: [Option].
+check_process_code(_Module, _OptionList) ->
+ erlang:nif_error(undefined).
+