Finding out the memory block size

7.1 LPAR mode z/VM guest

On an IBM Z® mainframe, memory is provided to Linux® as memory blocks of equal size.

Procedure

Use the lsmem command to find out the size of your memory blocks.

For example:

# lsmem
RANGE                                  SIZE   STATE REMOVABLE BLOCK
0x0000000000000000-0x000000006fffffff  1.8G  online       yes  0-13
0x0000000070000000-0x00000000ffffffff  2.3G offline           14-31

Memory block size:                128M
Total online memory:              1.8G
Total offline memory:             2.3G
Memmap on memory parameter:        yes

In the example, the block size is 128 MB.

Alternatively, you can read /sys/devices/system/memory/block_size_bytes. This sysfs attribute contains the block size in byte in hexadecimal notation.
For example:
```
# cat /sys/devices/system/memory/block_size_bytes
8000000
```
This hexadecimal value corresponds to 128 MB.