Re: [PATCH v2] mm/page_alloc: fix memalloc_nocma_{save/restore} APIs

[Andrew Morton]

On Fri, 24 Jul 2020 11:23:52 +0900 Joonsoo Kim <js1304@xxxxxxxxx> wrote:

> > > Second, clearing __GFP_MOVABLE in current_gfp_context() has a side effect
> > > to exclude the memory on the ZONE_MOVABLE for allocation target.
> >
> > More whoops.
> >
> > Could we please have a description of the end-user-visible effects of
> > this change?  Very much needed when proposing a -stable backport, I think.
> 
> In fact, there is no noticeable end-user-visible effect since the fallback would
> cover the problematic case. It's mentioned in the commit description. Perhap,
> performance would be improved due to reduced retry and more available memory
> (we can use ZONE_MOVABLE with this patch) but it would be neglectable.
> 
> > d7fefcc8de9147c is over a year old.  Why did we only just discover
> > this?  This makes one wonder how serious those end-user-visible effects
> > are?
> 
> As mentioned above, there is no visible problem to the end-user.

OK, thanks.  In that case, I don't believe that a stable backport is
appropriate?

(Documentation/process/stable-kernel-rules.rst)