Re: [PATCH 3/3] mm: page allocator: Drain per-cpu lists after directreclaim allocation fails

[Christoph Lameter]

On Thu, 9 Sep 2010, Mel Gorman wrote:

> > This will have the effect of never sending IPIs for slab allocations since
> > they do not do allocations for orders > PAGE_ALLOC_COSTLY_ORDER.
> >
>
> The question is how severe is that? There is somewhat of an expectation
> that the lower orders free naturally so it the IPI justified? That said,
> our historical behaviour would have looked like
>
> if (!page && !drained && order) {
> 	drain_all_pages();
> 	draiained = true;
> 	goto retry;
> }
>
> Play it safe for now and go with that?

I am fine with no IPIs for order <= COSTLY. Just be aware that this is
a change that may have some side effects. Lets run some tests and see
how it affect the issues that we are seeing.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/