On Wed, Aug 14, 2024 at 4:49 PM Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote: > > > We can also use such atomic counters in obj_cgroup_may_zswap() and > eliminate the rstat flush there as well. Same for zswap_current_read() > probably. zswap/zswapped are subtree-cumulative counters. Would that be a problem? > > Most in-kernel flushers really only need a few stats, so I am > wondering if it's better to incrementally move these ones outside of > the rstat framework and completely eliminate in-kernel flushers. For > instance, MGLRU does not require the flush that reclaim does as > Shakeel pointed out. > > This will solve so many scalability problems that all of us have > observed at some point or another and tried to optimize. I believe > using rstat for userspace reads was the original intention anyway. But yeah, the fewer in-kernel flushers we have, the fewer scalability/lock contention issues there will be. Not an expert in this area, but sounds like a worthwhile direction to pursue.
