Re: [RFC 0/7] introduce memory hinting API for external process

[Matthew Wilcox]

On Mon, May 20, 2019 at 12:52:47PM +0900, Minchan Kim wrote:
> IMHO we should spell it out that this patchset complements MADV_WONTNEED
> and MADV_FREE by adding non-destructive ways to gain some free memory
> space. MADV_COLD is similar to MADV_WONTNEED in a way that it hints the
> kernel that memory region is not currently needed and should be reclaimed
> immediately; MADV_COOL is similar to MADV_FREE in a way that it hints the
> kernel that memory region is not currently needed and should be reclaimed
> when memory pressure rises.

Do we tear down page tables for these ranges?  That seems like a good
way of reclaiming potentially a substantial amount of memory.