Re: [PATCH] make MADV_FREE lazily free memory

[Nick Piggin]

Nick Piggin wrote:
> Eric Dumazet wrote:

> > > Two things can happen here.
> > >
> > > If this program used the pages before the kernel needed
> > > them, the program will be reusing its old pages.
> >
> >
> >
> > ah ok, this is because accessed/dirty bits are set by hardware and not 
> > a page fault.
>
>
> No it isn't.

That is to say, it isn't required for correctness. But if the
question was about avoiding a fault, then yes ;)

But as Linus recently said, even hardware handled faults still
take expensive microarchitectural traps.

> > Is it true for all architectures ?
>
>
> No.


--
SUSE Labs, Novell Inc.
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