Re: [PATCH 0/5] make *_gate_vma accept mm_struct instead of task_struct II

Stephen Wilson
2011-03-10T16:54:14Z

On Thu, Mar 10, 2011 at 08:38:09AM -0800, Andi Kleen wrote:
> On Thu, Mar 10, 2011 at 08:00:32AM -0800, Andi Kleen wrote:
> > On Tue, Mar 08, 2011 at 07:31:56PM -0500, Stephen Wilson wrote:
> > > The only architecture this change impacts in any significant way is x86_64.
> > > The principle change on that architecture is to mirror TIF_IA32 via
> > > a new flag in mm_context_t.
> >
> > The problem is -- you're adding a likely cache miss on mm_struct for
> > every 32bit compat syscall now, even if they don't need mm_struct
> > currently (and a lot of them do not) Unless there's a very good
> > justification to make up for this performance issue elsewhere
> > (including numbers) this seems like a bad idea.
>
> Hmm I see you're only setting it on exec time actually on rereading
> the patches. I thought you were changing TS_COMPAT which is in
> the syscall path.
>
> Never mind. I have no problems with doing such a change on exec
> time.

OK. Great! Does this mean I have your ACK'ed by or reviewed by?

Thanks for taking a look!

--
steve