VMPAGE(8)

NAME
vmpage - report the current physical page usage

SYNOPSIS
vmpage [ namelist [ corefile ] ]

DESCRIPTION

vmpage classifies physical memory pages into the following categories.

physmem physmem
    Specifies the number of physical pages the kernel manages. Usually this is the amount of physical memory on the machine. In some systems, a few pages are considered to be managed by the prom monitor, and are not included in physmem.

startup startup
    Specifies the number of pages that the kernel has consumed by one intermediate point during startup (startup is also known as kernel initialization). The kernel will always use at least startup pages.

maxmem maxmem
    The difference between physmem and startup. maxmem Indicates the maximum amount of memory that is available for use by user programs at one intermediate point during startup. Since the kernel still needs to allocate additional pages, there will never actually be maxmem pages available for user processes.

pageable pageable
    The sum of cached and free pages (see below). There are pageable pages readily available for user processes.

scanned scanned
    A count of the number of pages scanned. Not all pages are scanned, since some pages are known to always be in use by the system.

locked locked
    Specifies the number of pages that are locked by the kernel. The kernel locks pages to prevent them from being changed. For example, while the kernel is establishing a page's identity, it will lock the page.

kept kept
    Specifies the number of pages that are “kept” by the kernel. The kernel “keeps” pages to prevent them from being removed. For example, the kernel will “keep” a page actively involved in an I/O operation.

cached cached
    Specifies the number of pages holding cached information which are available for reuse by user processes.

free free
    Specifies the number of pages on the freelist and ready for immediate allocation. Note that the system attempts to keep a certain number of pages readily available to reduce allocation latency.

OPTIONS
namelist
    Specifies the location of the system namelist. It defaults to /vmunix.
corefile
    Specifies the location of the system memory image. It defaults to /dev/kmem.

EXAMPLE

example% vmpage
vmpage: all results in decimal pages
physmem 510, startup 95, maxmem 415, pageable 320
scanned 432, locked 17, kept 95, cached 288, free 32

FILES
/vmunix
    default system namelist
/dev/kmem
    default system memory image

SEE ALSO
pagesize(1)

BUGS

vmpage is not synchronized with the kernel, so page usage can change while vmpage is running, leading to (minor) inaccuracies.