On Tue 29-01-19 18:40:58, Andrea Arcangeli wrote: > Hello, > > I'd like to attend the LSF/MM Summit 2019. I'm interested in most MM > topics and it's enlightening to listen to the common non-MM topics > too. > > One current topic that could be of interest is the THP / NUMA tradeoff > in subject. > > One issue about a change in MADV_HUGEPAGE behavior made ~3 years ago > kept floating around for the last 6 months (~12 months since it was > initially reported as regression through an enterprise-like workload) > and it was hot-fixed in commit > ac5b2c18911ffe95c08d69273917f90212cf5659, but it got quickly reverted > for various reasons. > > I posted some benchmark results showing that for tasks without strong > NUMA locality the __GFP_THISNODE logic is not guaranteed to be optimal > (and here of course I mean even if we ignore the large slowdown with > swap storms at allocation time that might be caused by > __GFP_THISNODE). The results also show NUMA remote THPs help > intrasocket as well as intersocket. > > https://lkml.kernel.org/r/20181210044916.GC24097@xxxxxxxxxx > https://lkml.kernel.org/r/20181212104418.GE1130@xxxxxxxxxx > > The following seems the interim conclusion which I happen to be in > agreement with Michal and Mel: > > https://lkml.kernel.org/r/20181212095051.GO1286@xxxxxxxxxxxxxx > https://lkml.kernel.org/r/20181212170016.GG1130@xxxxxxxxxx I am definitely interested in discussing this topic and actually wanted to propose it myself. I would add that part of the discussion was proposing a neww memory policy that would effectively enable per-vma node-reclaim like behavior. -- Michal Hocko SUSE Labs
