output of top command question

Giorgos Keramidas keramida at ceid.upatras.gr
Sun Nov 13 08:14:33 GMT 2005

On 2005-11-13 13:28, Gobbledegeek <gobbledegeek at gmail.com> wrote:
> Thanks. From the article I conclude that Active pages are:
> Pages with page-used bit set
> Inactive and cached refers to the different page queues.
> But I could not correlate "wired" with anything. Any Tips?

The virtual memory pages are not necessarilly associated with a page of
physical memory at all times.  They may be swapped out to disk if they
are active but there is a memory shortage for a particular task.  They
may be inactive or cached and end up being freed, etc.

The "wired" pages are attached to a physical memory page and are never
swapped out to disk.  In general, wired pages are those pages of the
physical memory that the kernel needs to keep around at all times,
because swapping them out is not possible for a variety of reasons
(i.e. they are used asynchronously by a hardware device for DMA
input/output, they contain paging information, and so on).

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