On 2/18/19 6:31 PM, Zi Yan wrote: > The purpose of proposing exchange_pages() is to avoid allocating any new > page, > so that we would not trigger any potential page reclaim or memory > compaction. > Allocating a temporary page defeats the purpose.
Compaction can only happen for order > 0 temporary pages. Even if you used single order = 0 page to gradually exchange e.g. a THP, it should be better than u64. Allocating order = 0 should be a non-issue. If it's an issue, then the system is in a bad state and physically contiguous layout is a secondary concern.
