Re: Deprecating and removing SLOB

[Roman Gushchin]

On Tue, Nov 08, 2022 at 04:55:29PM +0100, Vlastimil Babka wrote:
> Hi,
> 
> as we all know, we currently have three slab allocators. As we discussed at
> LPC [1], it is my hope that one of these allocators has a future, and two of
> them do not.
> 
> The unsurprising reasons include code maintenance burden, other features
> compatible with only a subset of allocators (or more effort spent on the
> features), blocking API improvements (more on that below), and my inability
> to pronounce SLAB and SLUB in a properly distinguishable way, without
> resorting to spelling out the letters.
> 
> I think (but may be proven wrong) that SLOB is the easier target of the two
> to be removed, so I'd like to focus on it first.

Great!

SLOB is not supported by the kernel memory accounting code, so if we'll
deprecate SLOB, we can remove all those annoying ifndefs.

But I wonder if we can deprecate SLAB too? Or at least use the moment to
ask every non-SLUB user on why they can't/don't want to use SLUB.
Are there any known advantages of SLAB over SLUB?

Also, for memory-constrained users we might want to add some guide on how
to configure SLUB to minimize the memory footprint.

Thank you!

Roman