lkml.org 
[lkml]   [2006]   [Jul]   [23]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateSun, 23 Jul 2006 06:03:09 -0700 (PDT)
FromChristoph Lameter <>
SubjectRe: [patch] slab: always follow arch requested alignments
On Sun, 23 Jul 2006, Heiko Carstens wrote:

> > 
> > See kmem_cache_create():
> >       /* 2) arch mandated alignment: disables debug if necessary */
> >         if (ralign < ARCH_SLAB_MINALIGN) {
> >                 ralign = ARCH_SLAB_MINALIGN;
> >                 if (ralign > BYTES_PER_WORD)
> >                         flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
> >         }
> 
> That is because if kmem_cache_create gets called with SLAB_HWCACHE_ALIGN set
> in flags then ralign will be greater or equal to ARCH_SLAB_MINALIGN:
> 
>         /* 1) arch recommendation: can be overridden for debug */ 
>         if (flags & SLAB_HWCACHE_ALIGN) { 
> 	        [...]
>                 ralign = cache_line_size(); 
> 	        [...]

Ok. Then you do not have a problem because ralign is greater than
ARCH_SLAB_MINALIGN.

> Therefore the test above will be passed and SLAB_RED_ZONE and SLAB_STORE_USER
> will stay in flags.
> cache_line_size() will return 256 on s390.

Looks as if you would have the correct alignment then. I still do not 
understand where the problem is since you want to align on an 8 byte 
boundary.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-07-23 15:05    [from the cache]
©2003-2008