shared memory usage tool - exmap

[John Berthels <jjberthels gmail com>]

Hi,

I've been working on a tool to help accurately account for shared
memory usage amongst multiple processes (following some of the
suggestions from the gnome wiki). This was suggested to me as a
relevant place to mention it - if not then sorry, and please let me
know if any other gnome lists might be appropriate.

You can get the current version here:

http://homepage.ntlworld.com/john.berthels/exmap

(latest version is 0.3).

Exmap comprises a kernel loadable module which exports the page
identity (pfn) for each page in each VMA of a selected process. A
perl/gtk2 app then uses this to walk the process list and build up a
picture of how pages are shared amongst mapped files and processes.

I've only got UI in for a fairly limited array of stats to far, but
hope to add much more (the underlying data structures have
significantly more info than is currently exposed). All suggestions on
what would other info would be useful (and perhaps ideas on the best
UI to present it) gratefully received.

I've previously bothered some people off-list about an precursor to
this tool (named shmap). Exmap uses a different approach (user space
correlation of page pfn's) rather than mapcount from struct page. This
appears to resolve the accuracy problems I was having with the
previous system.

I guess I'm saying it may be worth a second look :-)

regards,

jb