diff options
Diffstat (limited to 'lib/stdlib/doc/src')
| -rw-r--r-- | lib/stdlib/doc/src/gen_statem.xml | 35 |
1 files changed, 22 insertions, 13 deletions
diff --git a/lib/stdlib/doc/src/gen_statem.xml b/lib/stdlib/doc/src/gen_statem.xml index 91332fbdde..ec7f267c64 100644 --- a/lib/stdlib/doc/src/gen_statem.xml +++ b/lib/stdlib/doc/src/gen_statem.xml @@ -216,19 +216,23 @@ erlang:'!' -----> Module:StateName/3 if bad arguments are given. </p> <p> - The <c>gen_statem</c> process can go into hibernation (see - <seealso marker="erts:erlang#hibernate/3"> - <c>erlang:hibernate/3</c> - </seealso>) if a + The <c>gen_statem</c> process can go into hibernation; see + <seealso marker="proc_lib#hibernate/3"> + <c>proc_lib:hibernate/3</c>. + </seealso> + It is done when a <seealso marker="#state_function">state function</seealso> or <seealso marker="#Module:init/1"><c>Module:init/1</c></seealso> specifies <c>hibernate</c> in the returned <seealso marker="#type-action"><c>Actions</c></seealso> - list. This might be useful if the server is expected to be idle - for a long time. However use this feature with care - since hibernation implies at least two garbage collections - (when hibernating and shortly after waking up) and that is not - something you would want to do between each event on a busy server. + list. This feature might be useful to reclaim process heap memory + while the server is expected to be idle for a long time. + However, use this feature with care + since hibernation can be too costly + to use after every event; see + <seealso marker="erts:erlang#hibernate/3"> + <c>erlang:hibernate/3</c>. + </seealso> </p> </description> @@ -619,7 +623,8 @@ handle_event(_, _, State, Data) -> to wait for the next message. In hibernation the next non-system event awakens the <c>gen_statem</c>, or rather the next incoming message awakens the <c>gen_statem</c> - but if it is a system event it goes back into hibernation. + but if it is a system event + it goes right back into hibernation. </item> </list> </desc> @@ -645,9 +650,13 @@ handle_event(_, _, State, Data) -> </seealso> before going into <c>receive</c> to wait for a new external event. - If there are enqueued events the <c>hibernate</c> - is ignored as if an event just arrived and awakened - the <c>gen_statem</c>. + If there are enqueued events, + to prevent receiving any new event; a + <seealso marker="erts:erlang#garbage_collect/0"> + <c>garbage_collect/0</c> + </seealso> is done instead to simulate + that the <c>gen_statem</c> entered hibernation + and immediately got awakened by the oldest enqueued event. </p> </desc> </datatype> |