1DAXCTL-CREATE-DEVI(1) daxctl Manual DAXCTL-CREATE-DEVI(1)
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6 daxctl-create-device - Create a devdax device
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9 daxctl create-device [<options>]
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12 · Creates dax0.1 with 4G of size
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15 .ft C
16 # daxctl create-device -s 4G
17 [
18 {
19 "chardev":"dax0.1",
20 "size":4294967296,
21 "target_node":0,
22 "mode":"devdax"
23 }
24 ]
25 .ft
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28 · Creates devices with fully available size on all regions
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31 .ft C
32 # daxctl create-device -u
33 [
34 {
35 "chardev":"dax0.1",
36 "size":"15.63 GiB (16.78 GB)",
37 "target_node":0,
38 "mode":"devdax"
39 },
40 {
41 "chardev":"dax1.1",
42 "size":"15.63 GiB (16.78 GB)",
43 "target_node":1,
44 "mode":"devdax"
45 }
46 ]
47 .ft
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50 · Creates dax0.1 with fully available size on region id 0
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53 .ft C
54 # daxctl create-device -r 0 -u
55 {
56 "chardev":"dax0.1",
57 "size":"15.63 GiB (16.78 GB)",
58 "target_node":0,
59 "mode":"devdax"
60 }
61 .ft
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65 Creates dax device in devdax mode in dynamic regions. The resultant can
66 also be convereted to the system-ram mode which arranges for the dax
67 range to be hot-plugged into the system as regular memory.
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69 daxctl create-device expects that the BIOS or kernel defines a range in
70 the EFI memory map with EFI_MEMORY_SP. The resultant ranges mean that
71 it’s 100% capacity is reserved for applications.
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74 -r, --region=
75 Restrict the operation to devices belonging to the specified
76 region(s). A device-dax region is a contiguous range of memory that
77 hosts one or more /dev/daxX.Y devices, where X is the region id and
78 Y is the device instance id.
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80 -s, --size=
81 For regions that support dax device cretion, set the device size in
82 bytes. Otherwise it defaults to the maximum size specified by
83 region. This option supports the suffixes "k" or "K" for KiB, "m"
84 or "M" for MiB, "g" or "G" for GiB and "t" or "T" for TiB.
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86 The size must be a multiple of the region alignment.
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88 -a, --align
89 Applications that want to establish dax memory mappings with page
90 table entries greater than system base page size (4K on x86) need a
91 device that is sufficiently aligned. This defaults to 2M. Note that
92 "devdax" mode enforces all mappings to be aligned to this value,
93 i.e. it fails unaligned mapping attempts.
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95 --input
96 Applications that want to select ranges assigned to a device-dax
97 instance, or wanting to establish previously created devices, can
98 pass an input JSON file. The file option lets a user pass a JSON
99 object similar to the one listed with "daxctl list".
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101 The device name is not re-created, but if a "chardev" is passed in
102 the JSON file, it will use that to get the region id.
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104 Note that the JSON content in the file cannot be an array of
105 JSON objects but rather a single JSON object i.e. without the
106 array enclosing brackets.
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108 -u, --human
109 By default the command will output machine-friendly raw-integer
110 data. Instead, with this flag, numbers representing storage size
111 will be formatted as human readable strings with units, other
112 fields are converted to hexadecimal strings.
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114 -v, --verbose
115 Emit more debug messages
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118 Copyright © 2016 - 2020, Intel Corporation. License GPLv2: GNU GPL
119 version 2 http://gnu.org/licenses/gpl.html. This is free software: you
120 are free to change and redistribute it. There is NO WARRANTY, to the
121 extent permitted by law.
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124 daxctl-list(1),daxctl-reconfigure-device[1],daxctl-destroy-device[1]
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128daxctl 71.1 12/22/2020 DAXCTL-CREATE-DEVI(1)