Listing the available memory blocks

7.1 LPAR mode z/VM guest

List the available memory to find out how much memory is available and which memory blocks are online.

Procedure

Use the lsmem command to list your memory blocks.

For example:

# lsmem -a
RANGE                                  SIZE   STATE REMOVABLE BLOCK
0x0000000000000000-0x0000000007ffffff  128M  online       yes     0
0x0000000008000000-0x000000000fffffff  128M  online       yes     1
0x0000000010000000-0x0000000017ffffff  128M  online       yes     2
0x0000000018000000-0x000000001fffffff  128M  online       yes     3
0x0000000020000000-0x0000000027ffffff  128M  online       yes     4
0x0000000028000000-0x000000002fffffff  128M  online       yes     5
0x0000000030000000-0x0000000037ffffff  128M  online       yes     6
0x0000000038000000-0x000000003fffffff  128M  online       yes     7
0x0000000040000000-0x0000000047ffffff  128M  online       yes     8
0x0000000048000000-0x000000004fffffff  128M  online       yes     9
0x0000000050000000-0x0000000057ffffff  128M offline              10
0x0000000058000000-0x000000005fffffff  128M offline              11
0x0000000060000000-0x0000000067ffffff  128M offline              12
0x0000000068000000-0x000000006fffffff  128M offline              13
0x0000000070000000-0x0000000077ffffff  128M offline              14
0x0000000078000000-0x000000007fffffff  128M offline              15

Memory block size:                128M
Total online memory:              1.3G
Total offline memory:             768M
Memmap on memory parameter:        yes

Alternatively, you can list the configured memory blocks by listing the contents of /sys/devices/system/memory. Read the state attributes of each memory block to find out whether it is online or offline.

Example:

The following command results in an overview for all available memory blocks.

# grep -r --include="state" "line" /sys/devices/system/memory/
/sys/devices/system/memory/memory0/state:online
/sys/devices/system/memory/memory1/state:online
/sys/devices/system/memory/memory2/state:online
/sys/devices/system/memory/memory3/state:online
/sys/devices/system/memory/memory4/state:online
/sys/devices/system/memory/memory5/state:offline
/sys/devices/system/memory/memory6/state:offline
/sys/devices/system/memory/memory7/state:offline

Example

Note: Online blocks are in use by your Linux® instance. An offline block can be free to be added to your Linux instance but it might also be in use by another Linux instance.