Re: [PATCH v3 0/2] fadvise: support POSIX_FADV_NOREUSE

[KOSAKI Motohiro]

>>>  POSIX_FADV_DONTNEED = drop page cache if possible
>>>  POSIX_FADV_NOREUSE = reduce page cache eligibility
>>
>> Eeek.
>>
>> Your POSIX_FADV_NOREUSE is very different from POSIX definition.
>> POSIX says,
>>
>>        POSIX_FADV_NOREUSE
>>               Specifies that the application expects to access the specified data once  and  then
>>               not reuse it thereafter.
>>
>> IfI understand correctly, it designed for calling _before_ data access
>> and to be expected may prevent lru activation. But your NORESE is designed
>> for calling _after_ data access. Big difference might makes a chance of
>> portability issue.
> 
> You're right. NOREUSE is designed to implement drop behind policy.
> 
> I'll post a new patch that will plug this logic in DONTNEED (like the
> presious version), but without breaking the old /proc/sys/vm/drop_caches
> behavior.

Great!

thanks.



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