Re: [PATCH] MM: implement MADV_FREE lazy freeing of anonymous memory

Rik van Riel
2007-05-08T15:00:37Z

Nick Piggin wrote:

> We have percpu and cache affine page allocators, so when
> userspace just frees a page, it is likely to be cache hot, so
> we want to free it up so it can be reused by this CPU ASAP.
> Likewise, when we newly allocate a page, we want it to be one
> that is cache hot on this CPU.

Actually, isn't the clear page function capable of doing
some magic, when it writes all zeroes into the page, that
causes the zeroes to just live in CPU cache without the old
data ever being loaded from RAM?

That would sure be faster than touching RAM. Not sure if
we use/trigger that kind of magic, though :)

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