MPS issue job003448

Titlemps_arena_vm_growth is not documented
Assigned userGareth Rees
DescriptionIn mpsavm.h [1] the external symbol mps_arena_vm_growth is declared, but this is not documented.
AnalysisThis function sets the extendBy and extendMin values for the VM arena. What's the underlying user requirement?

Looking at the original customer request [2] that led to this function, it seems that the requirement here is to extend the arena only a little at a time when address space is tight, to leave address space available for other libraries. So there is a genuine requirement here.

From a design and documentation point of view, it would be nice if there were a parallel between the arena settings and the keyword arguments. At the moment we have:

Keyword argument Setter function
=================== ======================
COMMIT_LIMIT commit_limit_set
SPARE_COMMIT_LIMIT spare_commit_limit_set
PAUSE_TIME pause_time_set
-- clamp/park/release
-- vm_growth [*]

[*] Should probably be called extend_by to match other settings.
How foundinspection
Evidence[1] <>
[2] <>
Observed in1.111.0
Created byGareth Rees
Created on2013-03-19 11:06:24
Last modified byGareth Rees
Last modified on2018-08-28 11:17:40
History2013-03-19 GDR Created.
2014-04-10 GDR Analysis.