Today when a zram device has a backing device we change the ops to a new set which does not expose a rw_page method. This prevents the upper layers from trying to issue a synchronous rw. This has the downside that we penalize every rw even when it could possibly still be performed as a synchronous rw. This is just a proposal and I wanted to get feedback if people felt this was worthwhile. The motivation comes from what Minchan noted in the original change which introduced the synchronous behavior that it enhanches swap-in performance by about 45% [1]. So it'd be great if we could still get this benefit while using writeback. 1. https://lore.kernel.org/all/1505886205-9671-5-git-send-email-minchan@xxxxxxxxxx/ Brian Geffon (1): zram: Allow rw_page when page isn't written back. drivers/block/zram/zram_drv.c | 65 +++++++++++++++++++++-------------- drivers/block/zram/zram_drv.h | 1 + 2 files changed, 41 insertions(+), 25 deletions(-) -- 2.37.1.559.g78731f0fdb-goog
