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