Re: [LSF/MM TOPIC] guarantee natural alignment for kmalloc()?

[Michal Hocko <mhocko@kernel.org>]

On Thu 25-04-19 04:33:59, Matthew Wilcox wrote:
> On Thu, Apr 11, 2019 at 06:28:19AM -0700, Matthew Wilcox wrote:
> > On Thu, Apr 11, 2019 at 02:52:08PM +0200, Vlastimil Babka wrote:
> > > In the session I hope to resolve the question whether this is indeed the
> > > right thing to do for all kmalloc() users, without an explicit alignment
> > > requests, and if it's worth the potentially worse
> > > performance/fragmentation it would impose on a hypothetical new slab
> > > implementation for which it wouldn't be optimal to split power-of-two
> > > sized pages into power-of-two-sized objects (or whether there are any
> > > other downsides).
> > 
> > I think this is exactly the kind of discussion that LSFMM is for!  It's
> > really a whole-system question; is Linux better-off having the flexibility
> > for allocators to return non-power-of-two aligned memory, or allowing
> > consumers of the kmalloc API to assume that "sufficiently large" memory
> > is naturally aligned.
> 
> This has been scheduled for only the MM track.  I think at least the
> filesystem people should be involved in this discussion since it's for
> their benefit.

Agreed. I have marked it as a MM/IO/FS track, we just haven't added it
to the schedule that way. I still plan to go over all topics again and
consolidate the current (very preliminary) schedule. Thanks for catching
this up.

> Do we have an lsf-discuss mailing list this year?  Might be good to
> coordinate arrivals / departures for taxi sharing purposes.

Yes, the list should be established AFAIK and same address as last
years.

-- 
Michal Hocko
SUSE Labs