On Thu, Jan 28, 2010 at 09:23:56AM +0100, Manuel Lauss wrote: > >> This fix is only necessary with the SLAB allocator and CONFIG_DEBUG_SLAB > >> enabled; non-debug SLAB, SLUB do return nicely aligned addresses, > >> debug-enabled SLUB currently panics early in the boot process. > > > > Queued for 2.6.34 - should this also go into 2.6.33? > > 2.6.33 and .32 at least. That code has been in there since the dawn of 2.6; > the fact that nobody has tripped over this so far means that noone build kernels > with slab debugging (I tripped over this while looking for something else) or > the slab allocator behaviour changed recently. The behaviour of the slab has been like this as long as I can remember. Cherrypicking into the -stable branches as I'm writing this. > > Have you considered increasing the value ARCH_KMALLOC_MINALIGN which > > defaults to 8? Or your own slab cache of suitable alignment? The latter > > is more something for frequent allocations. > > I have to admit I know nothing about Linux' memory management. Are slab > caches not affected by the what I presume are "guard bytes" inserted into > the memory areas when slab debug is on? When creating a slab cache an alignment for objects allocated from this cache can be specified. Ralf
