Re: [PATCH 0/1] mm: Remove the SLAB allocator

From: Tobin C. Harding
Date: Wed Apr 10 2019 - 04:17:01 EST

On Wed, Apr 10, 2019 at 10:02:36AM +0200, Vlastimil Babka wrote:
> On 4/10/19 4:47 AM, Tobin C. Harding wrote:
> > Recently a 2 year old bug was found in the SLAB allocator that crashes
> > the kernel. This seems to imply that not that many people are using the
> > SLAB allocator.
> AFAIK that bug required CONFIG_DEBUG_SLAB_LEAK, not just SLAB. That
> seems to imply not that many people are using SLAB when debugging and
> yeah, SLUB has better debugging support. But I wouldn't dare to make the
> broader implication :)

Point noted.

> > Currently we have 3 slab allocators. Two is company three is a crowd -
> > let's get rid of one.
> >
> > - The SLUB allocator has been the default since 2.6.23
> Yeah, with a sophisticated reasoning :)
> > - The SLOB allocator is kinda sexy. Its only 664 LOC, the general
> > design is outlined in KnR, and there is an optimisation taken from
> > Knuth - say no more.
> >
> > If you are using the SLAB allocator please speak now or forever hold your peace ...
> FWIW, our enterprise kernel use it (latest is 4.12 based), and openSUSE
> kernels as well (with openSUSE Tumbleweed that includes latest
> stables). AFAIK we don't enable SLAB_DEBUG even in general
> debug kernel flavours as it's just too slow.

Ok, so that probably already kills this. Thanks for the response. No
flaming, no swearing, man! and they said LKML was a harsh environment ...

> IIRC last time Mel evaluated switching to SLUB, it wasn't a clear
> winner, but I'll just CC him for details :)

Probably don't need to take up too much of Mel's time, if we have one
user in production we have to keep it, right.

Thanks for your time Vlastimil.