Re: the new VMt

Rik van Riel
2000-09-25T16:41:02Z

On Mon, 25 Sep 2000, Linus Torvalds wrote:
> On Mon, 25 Sep 2000, Andrea Arcangeli wrote:
> >
> > But I'd much prefer to pass not only the classzone from allocator
> > to memory balancing, but _also_ the order of the allocation,
> > and then shrink_mmap will know it doesn't worth to free anything
> > that isn't contigous on the order of the allocation that we need.
>
> I suspect that the proper way to do this is to just make another gfp_flag,
> which is basically another hint to the mm layer that we're doing a multi-
> page allocation and that the MM layer should not try forever to handle it.
>
> In fact, that's independent of whether it is a multi-page
> allocation or not. It might be something like __GFP_SOFT - you
> could use it with single pages too.
>
> Thinking about it, we do have it already. It's called
> !__GFP_HIGH, and it used by all the GFP_USER allocations.

Hmm, I think these two are orthagonal.

__GFP_HIGH means that we are allowed to eat deeper into
the free list (maybe needed to avoid a deadlock freeing
pages)

__GFP_SOFT would mean "don't bother waiting for free pages",
which is something very different...

(I wouldn't want a user process to get killed simply because
kswapd is waiting for IO to finish on a swapout, in that case
we really do want to sleep for a while)

regards,

Rik
--
"What you're running that piece of shit Gnome?!?!"
-- Miguel de Icaza, UKUUG 2000

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