Messages in this thread | | | Subject | Re: What I suspect | Date | Wed, 8 Dec 1999 12:03:10 +0100 (MET) | From | (Rogier Wolff) |
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Alexander Viro wrote: > > > On Wed, 8 Dec 1999, Rogier Wolff wrote: > > > Linus Torvalds wrote: > > > So I've considered having a magic user-mapped page for quite some time, > > > because we have several of these cases where the kernel can generate code > > > at run-time to its own advantage. The sysenter thing is just an obvious > > > extension to this - allowing the kernel to generate whatever entry > > > sequence is the best for that particular CPU. > > > > Talking about "magic user-mapped pages": Some things like "getpid ()" > > are horrendously more inefficient than they need be. If there was a > > magic kernel-page that the user-app has read access to, then these > > calls would become enormously more efficient. > > And there goes any talk about not screwing TLB over this thing...
Right. But if your application happens to profit from the MEGA_FAST access to "getpid" and the likes, it is not a bad idea to have the tlb allocated for this use.
If you DON"T call getpid and friends, your application won't get the tlb entry allocated right?
Roger.
-- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 ** *-- BitWizard writes Linux device drivers for any device you may have! --* "I didn't say it was your fault. I said I was going to blame it on you."
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