On Mon, May 20, 2019 at 06:44:52PM -0700, Matthew Wilcox wrote: > 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 True for MADV_COLD(reclaiming) but false for MADV_COOL(deactivating) at this implementation. > way of reclaiming potentially a substantial amount of memory. Given that consider refauting are spread out over time and reclaim occurs in burst, that does make sense to speed up the reclaiming. However, a concern to me is anonymous pages since they need swap cache insertion, which would be wasteful if they are not reclaimed, finally.
