On Mon, Mar 25, 2019 at 10:27:46AM -0400, Nitesh Narayan Lal wrote: > I performed some experiments to see if the current implementation of > hinting breaks THP. I used AnonHugePages to track the THP pages > currently in use and memhog as the guest workload. > Setup: > Host Size: 30GB (No swap) > Guest Size: 15GB > THP Size: 2MB > Process: Guest is installed with different kernels to hint different > granularities(MAX_ORDER - 1, MAX_ORDER - 2 and MAX_ORDER - 3). Memhog > 15G is run multiple times in the same guest to see AnonHugePages usage > in the host. > > Observation: > There is no THP split for order MAX_ORDER - 1 & MAX_ORDER - 2 whereas > for hinting granularity MAX_ORDER - 3 THP does split irrespective of > MADVISE_FREE or MADVISE_DONTNEED. > -- > Regards > Nitesh > This is on x86 right? So THP is 2M and MAX_ORDER is 8M. MAX_ORDER - 3 ==> 1M. Seems to work out. -- MST
