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 13:06), Michal Hocko wrote:
[..]
> > > 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.
> 
> SLAB is not guaranteed to provide page size aligned object AFAIR.

oh, if there are no guarantees for page_sized allocations regardless
the .config then agree, won't help.

        -ss