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MG Mud User88f12472016-06-24 23:31:02 +02001CONCEPT
2 memory
3 swapping
4
5DESCRIPTION
6
7 TODO: This is out of date. Also document the relation with reset
8
9 (Collected from the Changelogs of the driver source)
10
11 The swapping algorithm has been changed. A test is done for
12 every object, comparing to a time stamp. If the object hasn't
13 been touched for a while, it could be subject for swapping.
14 Here comes the new thing: the function 'clean_up()' will be
15 called in the object. If the object still remains, the old
16 swapping algorithm will continue. That means that objects that
17 would never be subject to swapping (cloned objects) now have a
18 chance to self-destruct. It also means that rooms that
19 contains no important data can self-destruct. Self-destruction
20 saves more memory than swapping, as swapping only frees the
21 program code, while self-destruction also frees the internal
22 object representation.
23
24 The call of clean_up() has been modified. There is a constant
25 in config.h that defines how long time until clean_up is
26 called in an object. This call is independent of reset() and
27 swapping. It is recommended that the swapping time is
28 something short, like 10 minutes to 30 minutes, while the time
29 to clean_up is longer.
30
31 Fixed several bugs in the swap/reset/clean_up logic.
32 Recommended values are that the swap time is short (less than
33 30 minutes), and that reset time is medium (aprox 60 minutes),
34 and that time to clean_up is long (greater than 1.5h hours).
35 Any feedback of how to best tune these values are welcome. The
36 call of reset will be done once, and not yet again until the
37 object has been touched. This enables reset'ed objects to stay
38 swapped out. If you have a mudlib that has no ojbects that
39 defines 'clean_up', then you may better define this time as 0,
40 which means never call clean_up (and thus never swap the
41 object in needlessly). A well implemented usage of clean_up is
42 better than the swap algorithm, as even cloned objects can be
43 cleaned up and a self destruction is more efficient than
44 swapping (memory wise).
45
46 Changed mechanism of calling clean_up() slightly. Only objects
47 that defines the function will be called. And, only clean_up()
48 that returns non-zero will be called again. This will minimize
49 calls of clean_up(), while still cost very litte to maintain.
50
51 clean_up() now gets a flag as argument, which will be non-zero
52 if the the program of this object is used for inheritance by
53 other objects.
54
55SEE ALSO
56 clean_up(A), slow_shut_down(M), quota_demon(M), malloc(D)