Re: [PATCH v2] mm: Fix slab->page _count corruption.

[Christoph Lameter]

On Tue, 15 May 2012, Eric Dumazet wrote:

> > Following patch fixes it by moving page->_count out of cmpxchg_double
> > data. So that slub does no change it while updating slub meta-data in
> > struct page.
>
> I say again : Page is owned by slub, so get_page() or put_page() is not
> allowed ?

It is allowed since slab memory can be used for DMA.

> How is put_page() going to work with order-1 or order-2 allocations ?

It is always incrementing the page count of the head page.
--
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/