On Mon, 22 Nov 2021, Vlastimil Babka wrote:

It's no problem to have the real beginning of the object aligned, and the
prepended header not. The code already does that before this patch for the
kmalloc power-of-two alignments, where e.g. the object can be aligned to 256
bytes, but the prepended header to a smaller ARCH_KMALLOC_MINALIGN /
ARCH_SLAB_MINALIGN.

Ok but then the first object in a page may still have those issues.

quoted

I dont know but it seems that making slob that sophisticated is counter
productive. Remove SLOB?

I wouldn't mind, but somebody might :)

Well run a space efficiency analysis after this patch. If the memory used
is larger than SLUB (with the configuration for minimal data footprint)
then there is no reason for SLOB to continue.