Re: [PATCH 0/3] mm: Rework {enabled,defrag}_{show,store}

[Gavin Shan <gshan@redhat.com>]

On 1/30/20 6:49 PM, Michal Hocko wrote:
> On Thu 30-01-20 13:24:38, Gavin Shan wrote:
>> The inappropriate settings can be accepted by "enabled" and "defrag"
>> interface, as the following example shows. This series reworks the
>> related functions and fixes the issue by the way.
> 
> Do we really care? This is a root only interface and we do expect root
> to know how to use the interface.
> 

I'm not sure actually, but the behavior (suffix matching) isn't well documented
in admin-guide/mm/transhuge.rst at least. I think it's not bad to enforce a
full matching here because even root user can input something wrong :)

Thanks,
Gavin.

>>     # cat /sys/kernel/mm/transparent_hugepage/enabled
>>       always [madvise] never
>>     # echo neveroff > /sys/kernel/mm/transparent_hugepage/enabled
>>     # cat /sys/kernel/mm/transparent_hugepage/enabled
>>       always madvise [never]
>>
>> Gavin Shan (3):
>>    mm: Rework {enabled,defrag}_store()
>>    mm: Rework {enabled,defrag}_show()
>>    mm: Rework setup_transparent_hugepage()
>>
>>   mm/huge_memory.c | 216 +++++++++++++++++++++++++++--------------------
>>   1 file changed, 125 insertions(+), 91 deletions(-)
>>
>> -- 
>> 2.23.0
>>
>