1 What: /sys/bus/dax/devices/daxX.Y/al 1 What: /sys/bus/dax/devices/daxX.Y/align
2 Date: October, 2020 2 Date: October, 2020
3 KernelVersion: v5.10 3 KernelVersion: v5.10
4 Contact: nvdimm@lists.linux.dev 4 Contact: nvdimm@lists.linux.dev
5 Description: 5 Description:
6 (RW) Provides a way to specify 6 (RW) Provides a way to specify an alignment for a dax device.
7 Values allowed are constrained 7 Values allowed are constrained by the physical address ranges
8 that back the dax device, and 8 that back the dax device, and also by arch requirements.
9 9
10 What: /sys/bus/dax/devices/daxX.Y/ma 10 What: /sys/bus/dax/devices/daxX.Y/mapping
11 Date: October, 2020 11 Date: October, 2020
12 KernelVersion: v5.10 12 KernelVersion: v5.10
13 Contact: nvdimm@lists.linux.dev 13 Contact: nvdimm@lists.linux.dev
14 Description: 14 Description:
15 (WO) Provides a way to allocat 15 (WO) Provides a way to allocate a mapping range under a dax
16 device. Specified in the forma 16 device. Specified in the format <start>-<end>.
17 17
18 What: /sys/bus/dax/devices/daxX.Y/ma 18 What: /sys/bus/dax/devices/daxX.Y/mapping[0..N]/start
19 What: /sys/bus/dax/devices/daxX.Y/ma 19 What: /sys/bus/dax/devices/daxX.Y/mapping[0..N]/end
20 What: /sys/bus/dax/devices/daxX.Y/ma 20 What: /sys/bus/dax/devices/daxX.Y/mapping[0..N]/page_offset
21 Date: October, 2020 21 Date: October, 2020
22 KernelVersion: v5.10 22 KernelVersion: v5.10
23 Contact: nvdimm@lists.linux.dev 23 Contact: nvdimm@lists.linux.dev
24 Description: 24 Description:
25 (RO) A dax device may have mul 25 (RO) A dax device may have multiple constituent discontiguous
26 address ranges. These are repr 26 address ranges. These are represented by the different
27 'mappingX' subdirectories. The 27 'mappingX' subdirectories. The 'start' attribute indicates the
28 start physical address for the 28 start physical address for the given range. The 'end' attribute
29 indicates the end physical add 29 indicates the end physical address for the given range. The
30 'page_offset' attribute indica 30 'page_offset' attribute indicates the offset of the current
31 range in the dax device. 31 range in the dax device.
32 32
33 What: /sys/bus/dax/devices/daxX.Y/re 33 What: /sys/bus/dax/devices/daxX.Y/resource
34 Date: June, 2019 34 Date: June, 2019
35 KernelVersion: v5.3 35 KernelVersion: v5.3
36 Contact: nvdimm@lists.linux.dev 36 Contact: nvdimm@lists.linux.dev
37 Description: 37 Description:
38 (RO) The resource attribute in 38 (RO) The resource attribute indicates the starting physical
39 address of a dax device. In ca 39 address of a dax device. In case of a device with multiple
40 constituent ranges, it indicat 40 constituent ranges, it indicates the starting address of the
41 first range. 41 first range.
42 42
43 What: /sys/bus/dax/devices/daxX.Y/si 43 What: /sys/bus/dax/devices/daxX.Y/size
44 Date: October, 2020 44 Date: October, 2020
45 KernelVersion: v5.10 45 KernelVersion: v5.10
46 Contact: nvdimm@lists.linux.dev 46 Contact: nvdimm@lists.linux.dev
47 Description: 47 Description:
48 (RW) The size attribute indica 48 (RW) The size attribute indicates the total size of a dax
49 device. For creating subdivide 49 device. For creating subdivided dax devices, or for resizing
50 an existing device, the new si 50 an existing device, the new size can be written to this as
51 part of the reconfiguration pr 51 part of the reconfiguration process.
52 52
53 What: /sys/bus/dax/devices/daxX.Y/nu 53 What: /sys/bus/dax/devices/daxX.Y/numa_node
54 Date: November, 2019 54 Date: November, 2019
55 KernelVersion: v5.5 55 KernelVersion: v5.5
56 Contact: nvdimm@lists.linux.dev 56 Contact: nvdimm@lists.linux.dev
57 Description: 57 Description:
58 (RO) If NUMA is enabled and th 58 (RO) If NUMA is enabled and the platform has affinitized the
59 backing device for this dax de 59 backing device for this dax device, emit the CPU node
60 affinity for this device. 60 affinity for this device.
61 61
62 What: /sys/bus/dax/devices/daxX.Y/ta 62 What: /sys/bus/dax/devices/daxX.Y/target_node
63 Date: February, 2019 63 Date: February, 2019
64 KernelVersion: v5.1 64 KernelVersion: v5.1
65 Contact: nvdimm@lists.linux.dev 65 Contact: nvdimm@lists.linux.dev
66 Description: 66 Description:
67 (RO) The target-node attribute 67 (RO) The target-node attribute is the Linux numa-node that a
68 device-dax instance may create 68 device-dax instance may create when it is online. Prior to
69 being online the device's 'num 69 being online the device's 'numa_node' property reflects the
70 closest online cpu node which 70 closest online cpu node which is the typical expectation of a
71 device 'numa_node'. Once it is 71 device 'numa_node'. Once it is online it becomes its own
72 distinct numa node. 72 distinct numa node.
73 73
74 What: $(readlink -f /sys/bus/dax/dev 74 What: $(readlink -f /sys/bus/dax/devices/daxX.Y)/../dax_region/available_size
75 Date: October, 2020 75 Date: October, 2020
76 KernelVersion: v5.10 76 KernelVersion: v5.10
77 Contact: nvdimm@lists.linux.dev 77 Contact: nvdimm@lists.linux.dev
78 Description: 78 Description:
79 (RO) The available_size attrib 79 (RO) The available_size attribute tracks available dax region
80 capacity. This only applies to 80 capacity. This only applies to volatile hmem devices, not pmem
81 devices, since pmem devices ar 81 devices, since pmem devices are defined by nvdimm namespace
82 boundaries. 82 boundaries.
83 83
84 What: $(readlink -f /sys/bus/dax/dev 84 What: $(readlink -f /sys/bus/dax/devices/daxX.Y)/../dax_region/size
85 Date: July, 2017 85 Date: July, 2017
86 KernelVersion: v5.1 86 KernelVersion: v5.1
87 Contact: nvdimm@lists.linux.dev 87 Contact: nvdimm@lists.linux.dev
88 Description: 88 Description:
89 (RO) The size attribute indica 89 (RO) The size attribute indicates the size of a given dax region
90 in bytes. 90 in bytes.
91 91
92 What: $(readlink -f /sys/bus/dax/dev 92 What: $(readlink -f /sys/bus/dax/devices/daxX.Y)/../dax_region/align
93 Date: October, 2020 93 Date: October, 2020
94 KernelVersion: v5.10 94 KernelVersion: v5.10
95 Contact: nvdimm@lists.linux.dev 95 Contact: nvdimm@lists.linux.dev
96 Description: 96 Description:
97 (RO) The align attribute indic 97 (RO) The align attribute indicates alignment of the dax region.
98 Changes on align may not alway 98 Changes on align may not always be valid, when say certain
99 mappings were created with 2M 99 mappings were created with 2M and then we switch to 1G. This
100 validates all ranges against t 100 validates all ranges against the new value being attempted, post
101 resizing. 101 resizing.
102 102
103 What: $(readlink -f /sys/bus/dax/dev 103 What: $(readlink -f /sys/bus/dax/devices/daxX.Y)/../dax_region/seed
104 Date: October, 2020 104 Date: October, 2020
105 KernelVersion: v5.10 105 KernelVersion: v5.10
106 Contact: nvdimm@lists.linux.dev 106 Contact: nvdimm@lists.linux.dev
107 Description: 107 Description:
108 (RO) The seed device is a conc 108 (RO) The seed device is a concept for dynamic dax regions to be
109 able to split the region among 109 able to split the region amongst multiple sub-instances. The
110 seed device, similar to libnvd 110 seed device, similar to libnvdimm seed devices, is a device
111 that starts with zero capacity 111 that starts with zero capacity allocated and unbound to a
112 driver. 112 driver.
113 113
114 What: $(readlink -f /sys/bus/dax/dev 114 What: $(readlink -f /sys/bus/dax/devices/daxX.Y)/../dax_region/create
115 Date: October, 2020 115 Date: October, 2020
116 KernelVersion: v5.10 116 KernelVersion: v5.10
117 Contact: nvdimm@lists.linux.dev 117 Contact: nvdimm@lists.linux.dev
118 Description: 118 Description:
119 (RW) The create interface to t 119 (RW) The create interface to the dax region provides a way to
120 create a new unconfigured dax 120 create a new unconfigured dax device under the given region, which
121 can then be configured (with a 121 can then be configured (with a size etc.) and then probed.
122 122
123 What: $(readlink -f /sys/bus/dax/dev 123 What: $(readlink -f /sys/bus/dax/devices/daxX.Y)/../dax_region/delete
124 Date: October, 2020 124 Date: October, 2020
125 KernelVersion: v5.10 125 KernelVersion: v5.10
126 Contact: nvdimm@lists.linux.dev 126 Contact: nvdimm@lists.linux.dev
127 Description: 127 Description:
128 (WO) The delete interface for 128 (WO) The delete interface for a dax region provides for deletion
129 of any 0-sized and idle dax de 129 of any 0-sized and idle dax devices.
130 130
131 What: $(readlink -f /sys/bus/dax/dev 131 What: $(readlink -f /sys/bus/dax/devices/daxX.Y)/../dax_region/id
132 Date: July, 2017 132 Date: July, 2017
133 KernelVersion: v5.1 133 KernelVersion: v5.1
134 Contact: nvdimm@lists.linux.dev 134 Contact: nvdimm@lists.linux.dev
135 Description: 135 Description:
136 (RO) The id attribute indicate 136 (RO) The id attribute indicates the region id of a dax region.
137 137
138 What: /sys/bus/dax/devices/daxX.Y/me 138 What: /sys/bus/dax/devices/daxX.Y/memmap_on_memory
139 Date: January, 2024 139 Date: January, 2024
140 KernelVersion: v6.8 140 KernelVersion: v6.8
141 Contact: nvdimm@lists.linux.dev 141 Contact: nvdimm@lists.linux.dev
142 Description: 142 Description:
143 (RW) Control the memmap_on_mem 143 (RW) Control the memmap_on_memory setting if the dax device
144 were to be hotplugged as syste 144 were to be hotplugged as system memory. This determines whether
145 the 'altmap' for the hotplugge 145 the 'altmap' for the hotplugged memory will be placed on the
146 device being hotplugged (memma 146 device being hotplugged (memmap_on_memory=1) or if it will be
147 placed on regular memory (memm 147 placed on regular memory (memmap_on_memory=0). This attribute
148 must be set before the device 148 must be set before the device is handed over to the 'kmem'
149 driver (i.e. hotplugged into 149 driver (i.e. hotplugged into system-ram). Additionally, this
150 depends on CONFIG_MHP_MEMMAP_O 150 depends on CONFIG_MHP_MEMMAP_ON_MEMORY, and a globally enabled
151 memmap_on_memory parameter for 151 memmap_on_memory parameter for memory_hotplug. This is
152 typically set on the kernel co 152 typically set on the kernel command line -
153 memory_hotplug.memmap_on_memor 153 memory_hotplug.memmap_on_memory set to 'true' or 'force'."
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