Re: [Lsf-pc] LSFMMBPF proposal [MM]: Eliminate vmap/vmalloc lock contention

[Michal Hocko <mhocko@suse.com>]

On Mon 24-04-23 09:44:00, Uladzislau Rezki wrote:
> On Fri, Apr 21, 2023 at 02:03:43PM +0200, Michal Hocko wrote:
> > On Tue 28-02-23 17:42:43, Uladzislau Rezki wrote:
> > > Hello, LSF.
> > > 
> > > Title: Introduce a per-cpu-vmap-cache to eliminate a vmap lock contention
> > > 
> > > Description:
> > >  Currently the vmap code is not scaled to number of CPU cores in a system
> > >  because a global vmap space is protected by a single spinlock. Such approach
> > >  has a clear bottleneck if many CPUs simultaneously access to one resource.
> > > 
> > >  In this talk i would like to describe a drawback, show some data related
> > >  to contentions and places where those occur in a code. Apart of that i
> > >  would like to share ideas how to eliminate it providing a few approaches
> > >  and compare them.
> > 
> > It's been some time since you brough this up. Has there been any
> > progress on the topic? Do you still find it important to discuss it at
> > LSFMM?
> > 
> The idea about sequence was/is:
> 
> 1) Give an overview on the proposal;
> 2) Submit patches to address the problem;
> 3) Start a discussion over lkml with people who are interested in it;
> 4) Send out a complete solution.

Thanks for the clarification. The usual LSFMM format is strongly
discussion focused. Long presentations are usually discouraged and they
should only introduce people to the underlying problem to kick of a
discussion.

That being said, IMO it would be helpful to have some material on the
mailing list before any discussion could be productive.

Thanks!
-- 
Michal Hocko
SUSE Labs