Re: [Patch] mm tracepoints

Ingo Molnar
2009-03-06T18:25:42Z

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Fri, 2009-03-06 at 19:01 +0100, Ingo Molnar wrote:
> > * Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > > On Fri, 2009-03-06 at 18:38 +0100, Peter Zijlstra wrote:
> > > > On Fri, 2009-03-06 at 18:10 +0100, Ingo Molnar wrote:
> > > > > Looks pretty good and useful to me. I've Cc:-ed more mm folks,
> > > > > it would be nice to hear their opinion about these tracepoints.
> > > > >
> > > > > Andrew, Nick, Peter, what do you think?
> > > >
> > > > Bit sad we use the struct mm_struct * as mm identifier (little %lx vs %p
> > > > confusion there too), but I suppose there simply isn't anything better.
> > >
> > > > Things missing,
> > >
> > > Why only anon and filemap, that misses out on all the funky
> > > driver ->fault() handlers.
> >
> > btw., does it include shm faults? I think all of this would
> > be handled if the tracepoint was at handle_mm_fault(),
> > right?
>
> Partially, you wouldn't be able to do the file:offset thing
> you asked for.

That could be done further down in filemap_fault(). I.e. have an
all-encompassing tracepoint for all things [user-] page faults,
and a few opt-in places for more interesting specific fault
types.

> But yeah, also hugetlb seems to be missing.

Probably not that huge of an issue, given how rare those faults
are ;-)

Ingo