On Sun, Feb 26, 2023 at 11:02:53PM +0700, Ammar Faizi wrote: > ## Test wq_cpu_set > sudo mount -t btrfs -o rw,compress-force=zstd:15,commit=1500,wq_cpu_set=0.4.1.5 /dev/sda2 hdd/a; > cp -rf /path/folder_with_many_large_files/ hdd/a/test; > sync; # See the CPU usage in htop. > sudo umount hdd/a; This seems like the wrong model for setting cpu locality for internal filesystem threads. Users are used to controlling cpu sets and other locality behaviour of a task with wrapper tools like numactl. Wrap th emount command with a numactl command to limit the CPU set, then have the btrfs fill_super() callback set the cpu mask for the work queues it creates based on the cpu mask that has been set for the mount task. That is, I think the model should be "inherit cpu mask from parent task" rather than adding mount options. This model allows anything that numactl can control (e.g. memory locality) to also influence the filesystem default behaviour without having to add yet more mount options in the future.... -Dave. -- Dave Chinner david@xxxxxxxxxxxxx
