Re: [PATCH] mm: page_alloc: don't allocate page from memoryless nodes

From: Mike Rapoport
Date: Tue Feb 14 2023 - 07:46:45 EST


Now added x86 folks for real :)

The thread starts here:
https://lore.kernel.org/all/20230212110305.93670-1-zhengqi.arch@xxxxxxxxxxxxx/

On Tue, Feb 14, 2023 at 01:44:06PM +0200, Mike Rapoport wrote:
> (added x86 folks)
>
> On Tue, Feb 14, 2023 at 12:29:42PM +0100, David Hildenbrand wrote:
> > On 14.02.23 12:26, Qi Zheng wrote:
> > > On 2023/2/14 19:22, David Hildenbrand wrote:
> > > >
> > > > TBH, this is the first time I hear of NODE_MIN_SIZE and it seems to be a
> > > > pretty x86 specific thing.
> > > >
> > > > Are we sure we want to get NODE_MIN_SIZE involved?
> > >
> > > Maybe add an arch_xxx() to handle it?
> >
> > I still haven't figured out what we want to achieve with NODE_MIN_SIZE at
> > all. It smells like an arch-specific hack looking at
> >
> > "Don't confuse VM with a node that doesn't have the minimum amount of
> > memory"
> >
> > Why shouldn't mm-core deal with that?
>
> Well, a node with <4M RAM is not very useful and bears all the overhead of
> an extra live node.
>
> But, hey, why won't we just drop that '< NODE_MIN_SIZE' and let people with
> weird HW configurations just live with this?
>
> > I'd appreciate an explanation of the bigger picture, what the issue is and
> > what the approach to solve it is (including memory onlining/offlining).
> >
> > --
> > Thanks,
> >
> > David / dhildenb
> >
>
> --
> Sincerely yours,
> Mike.
>

--
Sincerely yours,
Mike.