Re: [PATCH V3 2/2] mm: compaction: limit illegal input parameters of compact_memory interface

[ye xingchen]

>> From: Minghao Chi <chi.minghao@xxxxxxxxxx>
>> 
>> Available only when CONFIG_COMPACTION is set. When 1 is written to
>> the file, all zones are compacted such that free memory is available
>> in contiguous blocks where possible.
>> But echo others-parameter > compact_memory, this function will be
>> triggered by writing parameters to the interface.
>> 
>> Applied this patch,
>> sh/$ echo 1.1 > /proc/sys/vm/compact_memory
>> sh/$ sh: write error: Invalid argument
>
>Didn't echo 2 > /proc/sys/vm/compact_memory used to work too?
yes
>
>Why kill that? Did the docs say only 1 was possible? If not
>perhaps the docs need to be updated?
In Documentation/admin-guide/sysctl/vm.rst:109 say: when 1 is written
to the file, all zones are compacted such that free memory is available
in contiguous blocks where possible.
So limit the value of interface compact_memory to 1.

Chi, and Ye