Re: [RFC 02/26] mm, slub: allocate private object map for validate_slab_cache()

[Vlastimil Babka]

On 5/25/21 1:33 PM, Mel Gorman wrote:
> On Tue, May 25, 2021 at 12:36:52PM +0200, Vlastimil Babka wrote:
>> > Most callers of validate_slab_cache don't care about the return value
>> > except when the validate sysfs file is written. Should a simply
>> > informational message be displayed for -ENOMEM in case a writer to
>> > validate fails and it's not obvious it was because of an allocation
>> > failure?
>> 
>> he other callers are all in the effectively dead resiliency_test() code, which
>> has meanwhile been replaced in mmotm by kunit tests meanwhile. But it's true
>> those don't check the results either for now.
>> 
> 
> Ok.
> 
>> > It's a fairly minor concern so whether you add a message or not
>> 
>> I think I'll rather fix up the tests. Or do you mean that -ENOMEM for a sysfs
>> write is also not enough and there should be a dmesg explanation for that case?
>> 
> 
> I mean the -ENOMEM for a sysfs write. While it's very unlikely, it might
> would explain an unexpected write failure.

On second thought, a failed GFP_KERNEL allocation will already generate a
prominent warning, so an extra message looks arbitrary.