Re: [PATCH v2 13/15] slab: use struct page for slab management

[Christoph Lameter]

On Wed, 16 Oct 2013, Joonsoo Kim wrote:

> -					 * see PAGE_MAPPING_ANON below.
> -					 */
> +	union {
> +		struct address_space *mapping;	/* If low bit clear, points to
> +						 * inode address_space, or NULL.
> +						 * If page mapped as anonymous
> +						 * memory, low bit is set, and
> +						 * it points to anon_vma object:
> +						 * see PAGE_MAPPING_ANON below.
> +						 */
> +		void *s_mem;			/* slab first object */
> +	};

The overloading of mapping has caused problems in the past since slab
pages are (or are they no longer?) used for DMA to disk. At that point the
I/O subsystem may be expecting a mapping in the page struct if this field
is not NULL.

--
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/