'ps' behavoir in Linux - Was - Re: array limits

[Jerry Rains]

On Friday 16 April 2004 14:37, Fairlight wrote:
> With neither thought nor caution, Jay Ashworth blurted:
> > I was talking about the SCO ps, which I believe was what he was talking
> > about; procps appears to use the brackets for "not a real process; part
> > of the kernel".
>
> I didn't believe so, as he was citing auxww at some point, and that's -not-
> SCO.  That's a BSD variant, and that's what proc-ps uses.

SuSE8.2 Professional.

>
> > But I could believe that /proc/$PID could be temporarily unpopulated
> > for processes which were swapped out; I'm not authoritatively familiar
> > with the semantics there.
>
> man ps:
> "
>        Programs swapped out to disk will be shown without command
>        line  arguments,  and  unless  the  c  option is given, in
>        brackets.
> "
>
> So we -know- that's accurate.

I've been pondering on why the process could be swapped out.  Now I am getting 
into an area where I am weak.  This system is one I put together in an 
attempt to get rid of Windows.  It is a desktop system running KDE that I use 
for mail, internet and Quicken (which means I run 'wine' (really CrossOver) 
on it.).  I assume that dclerk is being swapped out because of all the gui 
programs running in KDE.

I don't use it for filePro.  I just installed filePro on it for these tests 
because it is almost the same system that I use at work.  We use SuSE8.0 
Enterprise there.  I dialed into work and the ps auxww command works the same 
except it does list /appl/fp/dclerk instead of [dclerk].  Still no arguments.

Jerry

>
> And you, apparently, are correct--to an extent.  You couldn't grab your
> environ file contents from /proc on a swapped out process; the virtual file
> is empty.  However, you can see what fd's are in use and to what files they
> point in the /proc/$PID/fd/ directories.
>
> I didn't know that environ unpopulates when things are swapped out.
> Interesting.  Whatever led you to this conclusion, you happen to be right,
> and you've taught me something.  Thanks.
>
> Incidentally, -e gives you environment settings with proc-ps.  And yes,
> swapped processes turn up empty there as well--rather obviously, given
> where proc-ps gets its information.  :)
>
> mark->