Re: lookup on memory shortage

[Andrew Doran <ad%netbsd.org@localhost>]

On Fri, Oct 03, 2008 at 01:11:05PM +0200, Manuel Bouyer wrote:

> |CPU states:  0.0% user,  0.0% nice,  100% system,  0.0% interrupt,  0.0% idle

Presumably the pagedaemon is spinning.

> |              21 2       204           ca2729e0             xenbus

Will disk I/O stop if this thread cannot get CPU time?

> ddb bt/a isn't of much use:
> |db> bt/a ca271040

ca271040 is running on the CPU so it won't be of much use, right. 'bt' with
no arguments would have shown it: a stupid UI quirk in ddb. Can you add some
counters to the pagedaemon main loop to see what it is doing?

> The map for cc1 looks large but I'm not sure it explains where the
> memory did go. I wonder if there's some memory leak in the kernel that
> only show up with certain usage patterns (the box can build packages for
> days with almost no swap in use so it's not a slow memory leak).

Wired usage is low, so it does not look like a simple kernel memory leak.
There are plenty of pages that can be reclaimed but the pagedaemon is
failing to do so.

Andrew