On Sun, Nov 19, 2023 at 7:20 PM Huang, Ying <ying.huang@xxxxxxxxx> wrote: > > Chris Li <chriscli@xxxxxxxxxx> writes: > > > On Thu, Nov 16, 2023 at 12:19 PM Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote: > > That will cancel the batching effect on the swap slot free, making the > > common case for swapping faults take longer to complete, righ? > > If I recall correctly, the uncharge is the expensive part of the swap > > slot free operation. > > I just want to figure out what we are trading off against. This is not > > one side wins all situations. > > Per my understanding, we don't batch memcg uncharging in > swap_entry_free() now. Although it's possible and may improve > performance. swap_entry_free() does not do batching, it is at the caller level. I just checked. The batching is done in free_swap_slot() is still using swap slot cache and batching. It uses swapcache_free_entries() to batch free the swap_slots. That is where the uncharge happens per my understanding. Chris
