Re: [RFC Patch 6/9] Use virtual debug registers in process/threadhandling code

From: K.Prasad
Date: Thu Dec 04 2008 - 07:24:19 EST

On Wed, Dec 03, 2008 at 05:05:59PM -0800, Roland McGrath wrote:
> > > Hmm. The 64-bit version of __switch_to does the current change much
> > > earlier, before __switch_to_xtra and math_state_restore. I wonder if the
> > > 32-bit version could change to match. I can't see what in __switch_to_xtra
> > > would care either way, though I may be overlooking something. Ingo?
> >
> > Would it be better to move __switch_to_xtra down below the change to
> > current, rather than moving the change to current up above
> > __switch_to_xtra?
> I can't see that anything else in __switch_to_xtra cares either way.
> Thanks,
> Roland

That the grouse against the placement of
switch_to_thread_hw_breakpoint() is about additional code in the
hot-path, can we deal with this separately through a different patch?

I now have the patchset which provides only data breakpoint facility on
x86 (and x86_64) and has addressed your comments, ported against
2.6.28-rc7 which will be sent shortly. I'm thinking if the suggested
changes to the context-switching code can be handled later.


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