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SubjectRe: [PATCH] mm/hugetlb: suppress wrong warning info when alloc gigantic page
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On 19.02.21 20:14, Mike Kravetz wrote:
> On 2/19/21 4:39 AM, Chen Wandun wrote:
>> If hugetlb_cma is enabled, it will skip boot time allocation
>> when allocating gigantic page, that doesn't means allocation
>> failure, so suppress this warning info.
>>
>
> Normally the addition of warning messages is discouraged. However, in
> this case the additional message provides value. Why?
>
> Prior to the commit cf11e85fc08c, one could have a kernel command line
> that contains:
>
> hugepagesz=1G hugepages=16
>
> This would allocate 16 1G pages at boot time.
>
> After the commit, someone could specify a command line containing:
>
> hugepagesz=1G hugepages=16 hugetlb_cma=16G
>
> In this case, 16G of CMA will be reserved for 1G huge page allocations
> after boot time. The parameter 'hugepages=16' is ignored, and the warning
> message is logged. The warning message should only be logged when the
> kernel parameter 'hugepages=' is ignored.
>
> IMO, it make sense to log a warning if ignoring a user specified parameter.
> The user should not be attempting boot time allocation and CMA reservation
> for 1G pages.
>
> I do not think we should drop the warning as the it tells the user thay
> have specified two incompatible allocation options.
>

I agree. It has value.

--
Thanks,

David / dhildenb

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