On Thu, Sep 26, 2024 at 05:29:30PM +0000, Sridhar, Kanchana P wrote: > > > 3) Keep the approach in v7 where obj_cgroup_get/put is localized to > > > zswap_store_page for both success and error conditions, and any > > unwinding > > > state in zswap_store will take care of dropping references obtained from > > > prior successful writes (from this or prior invocations of zswap_store). > > > > I am also fine with doing that and doing the reference batching as a follow up. > > I think so too! We could try and improve upon (3) with reference batching > in a follow-up patch. Yeah, I agree. The percpu-refcounts are not that expensive, we should be able to live with per-page ops for now. One thing you *can* do from the start is tryget a pool reference in zswap_store(), to prevent the pools untimely demise while you work on it, and then in zswap_store_page() you can do gets instead of trygets. You'd have to rename zswap_pool_get() to zswap_pool_tryget() (which is probably for the best) and implement the trivial new zswap_pool_get().
