Check manual page of mem.vmalloc


Usage of Vmalloc address space

Distribution: official part of Check_MK
License: GPL
Supported Agents: Linux

The linux kernel keeps a part of the available address space free for usage by device drivers, e.g. for address mappings of IO devices into the physical address space. An example is the graphics driver used by the X server, which needs address mappings for communicating with the hardware. In /proc/meminfo that area is called VmallocTotal. On 32 bit architectures this area has a very limited size and is subject to fragmentation or consumption by buggy graphics drivers.

This check monitors the current usage of the the vmalloc address space and also the size of the largest available chunk (indicating the degree of fragmentation).

Discovery

A check is created if VmallocTotal is available in /proc/meminfo and only if the total size of the vmalloc area is less then 4 GB. This is generally only possible for 32 bit architectures.

Please add mem.vmalloc to ignored_checktypes if you do not need this check.