On Sat, May 21, 2022 at 03:19:24PM -0700, Andy Lutomirski wrote: > I can see a rather different use for this type of shared-pagetable > technology, though: monstrous MAP_SHARED mappings. For database and some VM > users, multiple processes will map the same file. If there was a way to > ensure appropriate alignment (or at least encourage it) and a way to handle > mappings that don't cover the whole file, then having multiple mappings > share the same page tables could be a decent efficiently gain. This doesn't > even need COW -- it's "just" pagetable sharing. The mshare proposal did not get a warm reception at LSFMM ;-( The conceptual model doesn't seem to work for the MM developers who were in the room. "Fear" was the most-used word. Not sure how we're going to get to a model of sharing page tables that doesn't scare people.
