On Tue, 2020-02-04 at 13:42 -0800, Mike Kravetz wrote: > On 2/4/20 12:33 PM, David Rientjes wrote: > > > > So it looks like this is fixing an obvious correctness issue but > > also now > > requires users to rewrite the sysctl if they want to decrease the > > min > > watermark. > > Moving the call to khugepaged_adjust_min_free_kbytes as described > above > would avoid the THP adjustment unless we were going to overwrite the > user defined value. Now, I am not sure overwriting the user defined > value > as is done today is actually the correct thing to do. > > Thoughts? > Perhaps we should never overwrite a user defined value? We might need to override user defined value if it is too low but overriding it silently is not quite right. We should print a warning at least. On the other hand, a user setting min_free_kbytes should know what they are doing and if they set it too low, they have been warned in the sysctl documentation. I would say we never override user defined value but print a warning if the value is too low and kernel would have adjusted it if it were not for the user defined value. -- Khalid
