Re: [PATCH 5/5] proc: export more page flags in /proc/kpageflags

From: KOSAKI Motohiro
Date: Tue Apr 28 2009 - 05:34:50 EST


>
> * Pekka Enberg <penberg@xxxxxxxxxxxxxx> wrote:
>
> > I have no idea how expensive tracepoints are but I suspect they
> > don't make too much sense for this particular scenario. After all,
> > kmemtrace is mainly interested in _allocation patterns_ whereas
> > this patch seems to be more interested in "memory layout" type of
> > things.
>
> My point is that the allocation patterns can be derived from dynamic
> events. We can build a map of everything if we know all the events
> that led up to it. Doing:
>
> echo 3 > /proc/sys/vm/drop_caches
>
> will clear 99% of the memory allocations, so we can build a new map
> from scratch just about anytime. (and if boot allocations are
> interesting they can be traced too)
>
> _And_ via this angle we'll also have access to the dynamic events,
> in a different 'view' of the same tracepoints - which is obviously
> very useful for different purposes.

I am one of most strongly want guys to MM tracepoint.
but No, many cunstomer never permit to use drop_caches.

I believe this patch and tracepoint are _both_ necessary and useful.



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