On Wed, 18 Jul 2007 08:59:40 -0700 Eugene Surovegin <[EMAIL PROTECTED]> wrote:
> On Wed, Jul 18, 2007 at 08:41:10AM -0500, Josh Boyer wrote: > > On Wed, 2007-07-18 at 01:34 -0700, Eugene Surovegin wrote: > > > On Wed, Jul 18, 2007 at 12:52:53AM -0700, Andrew Morton wrote: > > > > On Wed, 18 Jul 2007 00:07:50 -0700 (PDT) [EMAIL PROTECTED] wrote: > > > > > > > > > http://bugzilla.kernel.org/show_bug.cgi?id=8778 > > > > > > > > > > Summary: Ocotea board: kernel reports access of bad area > > > > > during > > > > > boot with DEBUG_SLAB=y > > > > > > Slab debugging is probably the culprit here. I had similar problem > > > couple of years ago, not sure something has changed since then, > > > haven't checked. > > > > > > When slab debugging was enabled it made memory allocations non L1 > > > cache line aligned. This is very bad for DMA on non-coherent cache > > > arches (PPC440 is one of those archs). > > > > > > I have a hack for EMAC which tries to "workaround" this problem: > > > http://kernel.ebshome.net/emac_slab_debug.diff > > > which might help. > > > > Would you be opposed to including that patch in mainline? > > Yes. I don't think it's the right way to fix this issue. IMO, the > right one is to fix slab allocator. You cannot change all drivers to > do this kind of cache flushing, and yes, I saw the same problem with > PCI based NIC I tried on Ocotea at the time. > hm. It should be the case that providing SLAB_HWCACHE_ALIGN at kmem_cache_create() time will override slab-debugging's offsetting of the returned addresses. Or is the problem occurring with memory which is returned from kmalloc(), rather than from kmem_cache_alloc()? A complete description of the problem would help here, please. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
