Re: [PATCH] mm: be more verbose for alloc_contig_range faliures

[David Hildenbrand]

On 18.02.21 09:56, Michal Hocko wrote:
> On Wed 17-02-21 08:36:03, Minchan Kim wrote:
> > alloc_contig_range is usually used on cma area or movable zone.
> > It's critical if the page migration fails on those areas so
> > dump more debugging message like memory_hotplug unless user
> > specifiy __GFP_NOWARN.
>
> I agree with David that this has a potential to generate a lot of output
> and it is not really clear whether it is worth it. Page isolation code
> already has REPORT_FAILURE mode which currently used only for the memory
> hotplug because this was just too noisy from the CMA path - d381c54760dc
> ("mm: only report isolation failures when offlining memory").
>
> Maybe migration failures are less likely to fail but still.

Side note: I really dislike that uncontrolled error reporting on memory 
offlining path we have enabled as default. Yeah, it might be useful for 
ZONE_MOVABLE in some cases, but otherwise it's just noise.

Just do a "sudo stress-ng --memhotplug 1" and see the log getting 
flooded ...

--
Thanks,

David / dhildenb