Dynamic pool creation has been supported for a long time, which maybe not used so much in practice. But with the per-memcg lru merged, the current structure of zswap_pool's lru and shrinker become less optimal. In the current structure, each zswap_pool has its own lru, shrinker and shrink_work, but only the latest zswap_pool will be the current used. 1. When memory has pressure, all shrinkers of zswap_pools will try to shrink its lru list, there is no order between them. 2. When zswap limit hit, only the last zswap_pool's shrink_work will try to shrink its own lru, which is inefficient. A more natural way is to have a global zswap lru shared between all zswap_pools, and so is the shrinker. The code becomes much simpler too. Another optimization is changing zswap_pool kref to percpu_ref, which will be taken reference by every zswap entry. So the scalability is better. Testing kernel build in tmpfs with memory.max=2GB (zswap shrinker and writeback enabled with one 50GB swapfile). mm-unstable zswap-global-lru real 63.20 63.12 user 1061.75 1062.95 sys 268.74 264.44 Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx> --- Chengming Zhou (2): mm/zswap: global lru and shrinker shared by all zswap_pools mm/zswap: change zswap_pool kref to percpu_ref mm/zswap.c | 183 +++++++++++++++++++++++++------------------------------------ 1 file changed, 76 insertions(+), 107 deletions(-) --- base-commit: 191d97734e41a5c9f90a2f6636fdd335ae1d435d change-id: 20240210-zswap-global-lru-94d49316178b Best regards, -- Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>