DAXCTL-RECONFIGURE-DEVICE(1) daxctl Manual DAXCTL-RECONFIGURE-DEVICE(1) (NAME) daxctl-reconfigure-device - dax (SYNOPSIS) daxctl reconfigure-device [...] [<>] (DESCRIPTION) dax. devdax system-ram dax (hot- plug) . devdax famfs famfs fsdev_dax (bind) ( ). . dax . dax-bus . daxctl-migrate-device-model(1) . dax-class ( dax_pmem_compat) : # daxctl reconfigure-device --mode=system-ram --region=0 all libdaxctl: daxctl_dev_disable: dax3.0: error: device model is dax-class dax3.0: disable failed: Operation not supported error reconfiguring devices: Operation not supported reconfigured 0 devices daxctl-reconfigure-device movable (online) . (hot-plugged) . /sys/devices/system/memory/auto_online_blocks udev . (race condition) daxctl movable . (zone) . --no-online . . daxctl ( /sys/devices/system/memory/auto_online_blocks) system-ram . --force (override )..SH " (THEORY OF OPERATION)" device-dax DAX ( page-cache) . /dev/daxX.Y X (region-id) Y (instance-id) . device-dax : 1. (PMEM) "devdax" . "ndctl create-namespace --help" CONFIG_DEV_DAX_PMEM . . device-dax . 2. (Soft Reserved) . EFI EFI_MEMORY_SP "Special Purpose" . CONFIG_DEV_DAX_HMEM . . () device-dax . (Soft Reservation) EFI + ACPI EFI_MEMORY_SP (proximity domains) ACPI "System RAM" . SRAT SLIT HMAT / / . HMAT sysfs . NUMAPERF . NUMA "Soft Reserved" /proc/iomem "Soft Reserved" . CONFIG_EFI_SOFT_RESERVE CONFIG_EFI_SOFT_RESERVE ( 5.5) efi=nosoftreserve device-dax NUMA - . device-dax DAXCTL(1) "System RAM" (back end) LIBVMEM . . (EXAMPLES) o dax0.0 system-ram (online) # daxctl reconfigure-device --mode=system-ram --no-online dax0.0 [ { "chardev":"dax0.0", "size":16777216000, "target_node":2, "mode":"system-ram" } ] o dax0.0 devdax (offline) # daxctl reconfigure-device --human --mode=devdax --force dax0.0 { "chardev":"dax0.0", "size":"15.63 GiB (16.78 GB)", "target_node":2, "mode":"devdax" } o dax0.0 ( devdax) famfs # daxctl reconfigure-device --mode=famfs dax0.0 [ { "chardev":"dax0.0", "size":16777216000, "target_node":2, "mode":"famfs" } ] o dax region0 system-ram # daxctl reconfigure-device --mode=system-ram --region=0 all [ { "chardev":"dax0.0", "size":16777216000, "target_node":2, "mode":"system-ram" }, { "chardev":"dax0.1", "size":16777216000, "target_node":3, "mode":"system-ram" } ] o some-service numactl 0 1 2 ( daxctl_dev_get_target_node() daxctl list) # daxctl reconfigure-device --mode=system-ram dax0.0 [ { "chardev":"dax0.0", "size":16777216000, "target_node":2, "mode":"system-ram" } ] # numactl --cpunodebind=0-1 --membind=2 -- some-service --opt1 --opt2 o dax # daxctl reconfigure-device dax0.1 -s 16G reconfigured 1 device # daxctl reconfigure-device dax0.1 -s 0 reconfigured 1 device (OPTIONS) -r, --region= () . device-dax /dev/daxX.Y X Y . -s, --size= dax . "k" "K" KiB "m" "M" MiB "g" "G" GiB "t" "T" TiB . . -m --mode . -a, --align dax (K x86) . 2M . "devdax" . -m --mode . -m, --mode= () dax . o "system-ram": (hotplug) . o "devdax": "device dax". (hot-unplugging) kmem . devdax . o "famfs": fsdev_dax famfs ( ). "devdax" "system-ram" . -N, --no-online system-ram online_movable (online) . . -C, --check-config daxctl . daxctl-reconfigure-device systemd-udevd . reconfigure-device dax . PERSISTENT RECONFIGURATION . --no-movable --movable . movable ( ) . . --movable ( ) . -f, --force o "system-ram" "devdax" (offline) . daxctl . "devdax" NUMA dax . o system-ram . . . -u, --human . . -v, --verbose (PERSISTENT RECONFIGURATION) (mode) daxctl . . devdax . dax . daxctl . daxctl . reconfigure-device . : [reconfigure-device ] nvdimm.uuid = mode = (default: system-ram) online = (default: true) movable = (default: true) devdax devdax (online movable) system-ram system-ram (online) (not movable) . . ( dax0.0 ) . [reconfigure-device dax0] nvdimm.uuid = ed93e918-e165-49d8-921d-383d7b9660c5 mode = devdax [reconfigure-device dax1] nvdimm.uuid = f36d02ff-1d9f-4fb9-a5b9-8ceb10a00fe3 mode = system-ram [reconfigure-device dax2] nvdimm.uuid = f36d02ff-1d9f-4fb9-a5b9-8ceb10a00fe3 mode = system-ram online = true movable = false devdax system-ram . ndctl create-namespace --mode=devdax | \ jq -r "\"[reconfigure-device $(uuidgen)]\", \"nvdimm.uuid = \(.uuid)\", \"mode = system-ram\"" >> $config_path daxctl /etc/daxctl.conf.d/ .conf . ini {section, subsection} /etc/daxctl.conf.d/ ..SH " (COPYRIGHT)" (C) 2016 - 2022, Intel Corporation. GPLv2: GNU GPL 2 . : . . (SEE ALSO) daxctl-list(1),daxctl-migrate-device-model[1] daxctl 2026-06-30 DAXCTL-RECONFIGURE-DEVICE(1)