Subject: Re: Bad response...
To: Aidan Kehoe <kehoea@parhasard.net>
From: Johnny Billquist <bqt@Update.UU.SE>
List: current-users
Date: 08/31/2004 17:20:35
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On Tue, 31 Aug 2004, Aidan Kehoe wrote:

> Ar an t-aon=FA l=E1 is triochad de m=ED L=FAnasa, scr=EDobh Johnny Bill=
quist:
>
> > On a different note, then. What *exacly* does vm.filemax say???
>
> sysctl(3):
>
>     [...]
>     VM_FILEMAX
>             The percentage of physical memory which will be reclaimed f=
rom
>             other types of memory usage to store cached file data.

Ok. Correct me if I'm wrong now then, and fill in the blanks.
If the file cache is at VM_FILEMIN or less, other memory grabbers cannot=20
"steal" the pages used by the file cache.
If the file cache is at less than VM_FILEMAX, it will "steal" pages from=20
other memory classes, when needed.

But obviously, the file cache can also grab more memory than VM_FILEMAX.=20
At what conditions does this happen?
Only if the memory is unclaimed? I find that hard to believe, since all=20
memory grabbers might then take up to MAX, and the first one to claim=20
memory above MAX would have it for life (if the tuning was set so that th=
e=20
sum of all MAX was less than 100). Or does it work that way?

> > The system will use more if more is available. I imagine I understand=
 what
> > vm.filemin says...
>
> (This isn't Linux, the man pages are worth reading ...)

Sorry, I did find that manpage after I started all this, but now I'm at=20
the point where I'm once more into the undocumented (I believe) land.

And yes, man-pages are often worth reading, but they are sometimes very=20
hard to find. "man -k" have become almost hopeless as well, since there=20
are perl, kerberos, crypt, X11 and god knows what else that have a large=20
number of subjects that you often get hits on when trying to search for=20
anything.
I'd really like to see a hierarchical system of documentation.
The man-pages were not even good when Unix was young. :-)

 	Johnny

Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt@update.uu.se           ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol
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