Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address")

[Sergey Senozhatsky]

On (04/18/17 09:33), Michal Hocko wrote:
[..]
> > Another approach is the API does normal thing for non-aligned prefix and
> > tail space and fast thing for aligned space.
> > Otherwise, it would be happy if the API has WARN_ON non-page SIZE aligned
> > address.
> 
> copy_page is a performance sensitive function and I believe that we do
> those tricks exactly for this purpose.

a wild thought,

use
	#define copy_page(to,from)	memcpy((to), (from), PAGE_SIZE)

when DEBUG_SLAB is set? so arch copy_page() (if provided by arch)
won't be affected otherwise.

	-ss