Subject: Re: swap into the void?
To: Christian Groessler <cpg@aladdin.de>
From: Chuck Silvers <chuq@chuq.com>
List: tech-kern
Date: 08/01/2002 19:39:26
"swapped out" doesn't mean what you think it does. :-)
these days, "swapped out" just means that the pages for that process's
kernel stack are allowed to be written to swap and freed, not that this
has necessarily happened. the reason why it isn't actually happening
is that the memory usage-balancing code sees that there's not enough
swap-backed memory in use to warrant reusing any of it yet, so the pages
stay in memory.
-Chuck
On Fri, Aug 02, 2002 at 01:30:15AM +0200, Christian Groessler wrote:
> Hi,
>
> I'm currently doing a build of the 1.6 branch on my macppc machine,
> and I notice that "ps -aux" reports the original ./build.sh as being
> swapped out:
>
> root 14166 0.0 0.4 544 1068 p1 SN+ 1:08AM 0:00.11 /usr/local/tools/bin/nbmake install BUILD_tools n
> root 14165 0.0 0.0 612 376 p1 SWN+ - 0:00.00 /bin/sh -ec (cd /local/netbsdsrc-1.6/src && /usr/
> root 18795 0.0 0.0 556 1060 p1 SWN+ - 0:00.00 /usr/local/tools/bin/nbmake do-build
> root 18794 0.0 0.0 612 376 p1 SWN+ - 0:00.00 /bin/sh -ec (cd /local/netbsdsrc-1.6/src && /usr/
> root 1071 0.0 0.0 492 1068 p1 SWN+ - 0:00.00 /usr/local/tools/bin/nbmake build
> root 261 0.0 0.0 636 460 p1 SWN+ - 0:00.00 /bin/sh ./build.sh
> root 248 0.0 0.0 764 916 p1 SWs - 0:00.00 bash
> root 247 0.0 0.4 412 948 ?? Ss 12:08AM 0:04.93 SCREEN (screen-3.9.10)
>
> but at the same time "swapctl -lk" tells me
>
> bash-2.05# swapctl -lk
> Device 1K-blocks Used Avail Capacity Priority
> /dev/wd1b 1048576 0 1048576 0% 0
>
> No swap space used!?
>
> Where are the swapped out processes swapped to?
>
> confused,
> chris