Messages in this thread | | | Date | Fri, 20 Oct 2006 17:38:32 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [PATCH 1/3] Fix COW D-cache aliasing on fork |
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On Sat, 21 Oct 2006, Ralf Baechle wrote: > > > That said, maybe nobody does that. Virtual caches are a total braindamage > > in the first place, so hopefully they have limited use. > > On MIPS we never had pure virtual caches.
Ok, so on MIPS my schenario doesn't matter.
I think (but may be mistaken) that ARM _does_ have pure virtual caches with a process ID, but people have always ended up flushing them at context switch simply because it just causes too much trouble.
Sparc? VIPT too? Davem?
I have absolutely zero clue about s390.
Anyway, it sounds to me like this is too big to decide for 2.6.19 anyway, and as far as I can tell this i snot a regression, right? Ie we've always had the aliasing issue. Ralf?
But it would be good to have something for the early -rc1 sequence for 2.6.20, and maybe the MIPS COW D$ patches are it, if it has performance advantages on MIPS that can also be translated to other virtual cache users..
> Be sure I'm sending a CPU designers a strong message about aliases.
Castration. That's the best solution. We don't want those people procreating.
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