Re: [PATCH] make MADV_FREE lazily free memory

Nick Piggin
2007-04-12T06:12:42Z

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.