Re: [PATCH 0/13] maps: pagemap, kpagemap, and related cleanups

[Nick Piggin <nickpiggin@yahoo.com.au>]

Andrew Morton wrote:
> On Fri, 13 Apr 2007 11:42:29 +1000 Nick Piggin <nickpiggin@yahoo.com.au> wrote:

> > Maybe. How about LRU? Reclaim performance is bad, and you want to work out
> > which pages keep going off the end of it, or which pages keep getting
> > written out via it, or who's pages are on the active list, forcing mine
> > out.
>
>
> I guess we have static analysis versus dynamic.  The interfaces which Matt
> is proposing are suited to answering the question "what is my memory being
> used for" (static).  They're unlikely to be useful for answering the question
> "what's happening in the VM" (dynamic).  Systemtap is probably better for the
> dynamic analysis.

"what is my memory being used for *now*" ;)


> I guess one could generate an answer to the static question with systemtap,
> by accumulating running counts across the application lifetime and then
> snapshotting them.  Sounds hard though.

Can't you just traverse arbitrary kernel data structures at a given point
in time, exactly like the /proc/ call is doing?

--
SUSE Labs, Novell Inc.
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