Re: [PATCH v2 2/2] mm/pageblock: remove false sharing in pageblock_flags

[Anshuman Khandual]

On 08/19/2020 11:17 AM, Alex Shi wrote:
> Current pageblock_flags is only 4 bits, so it has to share a char size
> in cmpxchg when get set, the false sharing cause perf drop.
> 
> If we incrase the bits up to 8, false sharing would gone in cmpxchg. and
> the only cost is half char per pageblock, which is half char per 128MB
> on x86, 4 chars in 1 GB.

Agreed that increase in memory utilization is negligible here but does
this really improve performance ?