On Sun, 1 May 2022 13:26:34 -0700 Davidlohr Bueso <dave@xxxxxxxxxxxx> wrote: > On Wed, 27 Apr 2022, Matthew Wilcox wrote: > > >On Wed, Apr 27, 2022 at 10:33:31AM -0700, Andrew Morton wrote: > >> On Wed, 27 Apr 2022 14:08:39 +0000 Liam Howlett <liam.howlett@xxxxxxxxxx> wrote: > >> > The benchmarks are around the same as they have always been. > >> > >> So it's presently a wash. > >> > >> That makes "the plan" (below) really critical, otherwise there seems > >> little point in merging this code at this time? > >> > >> Please send me many very soothing words about how confident we should > >> be that the plan will be implemented and that it shall be good? > > > >Yes, performance-wise it's a wash. However, Davidlohr was very > >impressed that it was a wash because we're actually getting rid of three > >data structures here; the linked list, the rbtree and the vmacache. > >His opinion was that we should push the maple tree in now, in advance > >of the future RCU uses. > > Yes I like the maple tree, and at this stage I don't think we can ask > for more from this series wrt the MM - albeit there seems to still be > some folks reporting breakage. Fundamentally I see Liam's work to (re)move > complexity out of the MM (not to say that the actual maple tree is not > complex) by consolidating the three complimentary data structures very > much worth it considering performance does not take a hit. This was > very much a turn off with the range locking approach, which worst case > scenario incurred in prohibitive overhead. Also as Liam and Matthew > have mentioned, RCU opens up a lot of nice performance opportunities, > and in addition academia[1] has shown outstanding scalability of address > spaces with the foundation of replacing the locked rbtree with RCU > aware trees. Thanks. That sounded like a wordy acked-by to me? :) Liam, I think the above is useful background for the [0/N]. > [1] https://pdos.csail.mit.edu/papers/rcuvm:asplos12.pdf As is that. The paper seems shockingly relevant. Do we know the authors or is it a cosmic coincidence?
