From: Kairui Song <kasong@xxxxxxxxxxx> This series removes the global swap cgroup lock. The critical section of this lock is minimal but it's still a bottle neck for mass parallel swap workloads. Improvement of this series is more significant after the si lock rework: https://lore.kernel.org/linux-mm/20241022192451.38138-1-ryncsn@xxxxxxxxx/ But this series works very well on its own. Testing using 64G brd and build with build kernel with make -j96 in 1.5G memory cgroup using 4k folios showed below improvement (10 test run): Before this series: Sys time: 10730.08 (stdev 49.030728) Real time: 171.03 (stdev 0.850355) After this series: Sys time: 9612.24 (stdev 66.310789), -10.42% Real time: 159.78 (stdev 0.577193), -6.57% With 64k folios and 2G memcg: Before this series: Sys time: 7626.77 (stdev 43.545517) Real time: 136.22 (stdev 1.265544) After this series: Sys time: 6936.03 (stdev 39.996280), -9.06% Real time: 129.65 (stdev 0.880039), -4.82% Sequential swapout of 8G 4k zero folios (24 test run): Before this series: 5461409.12 us (stdev 183957.827084) After this commit: 5420447.26 us (stdev 196419.240317) Kairui Song (4): mm, memcontrol: avoid duplicated memcg enable check mm/swap_cgroup: remove swap_cgroup_cmpxchg mm/swap_cgroup: simplify swap cgroup definitions mm, swap_cgroup: remove global swap cgroup lock include/linux/swap_cgroup.h | 2 - mm/memcontrol.c | 2 +- mm/swap_cgroup.c | 110 ++++++++++++++++-------------------- 3 files changed, 51 insertions(+), 63 deletions(-) -- 2.47.0
