Mailinglist Archive: opensuse (2217 mails)

[Bill Anderson <bill@xxxxxxxxxxxxxxxxx>]

Jonathan Arnold wrote:
> David C. Rankin wrote:
>   
> > David C. Rankin wrote:
> >     
> > > Carlos E. R. wrote:
> > >       
> > > > The Thursday 2007-09-20 at 06:41 -0500, David C. Rankin wrote:
> > > >
> > > >         
> > > > > Ok,
> > > > >         Now I'm confused... After all of the discussion about ram size/swap
> > > > > size, I decided to try and make my 1G Toshiba P35 laptop start swapping
> > > > > stuff to the swap file.
> > > > >         I opened everything I could think of, 4 konsoles, 2 Open Office files,
> > > > > 3 Gimps, 2 Firefox, 2 Kongueror, Kjot, knotes, ksnapshot, kstars,
> > > > > Amarok, Thunderbird and several more, but the memory required, as shown
> > > > > by top, *never* exceeded 1G. The more I would open, the more slight
> > > > > slowness would occur, but I *always* had 13k - 15k of memory left and
> > > > > *nothing* was ever written to the swap file.
> > > > >           
> > > > It probably was taken from the memory used for buffers. The command 
> > > > 'swapon -s' will also tell you the used swap and where.
> > > >
> > > > Just suspend the machine to disk, and get back: you will see that many 
> > > > things will remain swaped out. The computer is slow right after waking up, 
> > > > because needed things are not in ram and have to be read from disk. After 
> > > > a while, it is faster than before because it has got ridden himself of 
> > > > useless chunks in memory that has ben swapped out.
> > > >         
> > > [root Rankin-P35a:/home/david] # swapon -s
> > > Filename                        Type            Size    Used    Priority
> > > /dev/hda5                       partition       2104472 0       -1
> > >
> > >         What is strange is that man swapon says -s is equivalent to cat
> > > /proc/swaps. I do not have a /proc/swaps to be found. Hmm.. Thoughts?
> > >
> > >
> > >       
> > Let me correct that. I do have a swaps it has the permissions:
> >
> > [root Rankin-P35a:/home/david] # ll /proc/swaps
> > -r--r--r-- 1 root root 0 2007-09-20 07:33 /proc/swaps
> >
> > The permission would seem to prevent writing to swap. What should the
> > permissions for swap be?
> >     
>
> Your normal user wouldn't write to it anyway. It's just a special informational
> file (like most if not all the files found in /proc), it isn't the actual swap file.
> The actual swap partition is specified in the /etc/fstab file.
>
>   
The /proc directory is really a reflection of kernel data structures. 
They are not real files and directories. Through the magic of VFS, 
system calls to these files and directories invoke routines that read 
the current kernel data. Under /proc/sys, there are nodes that are 
tunable kernel parameters, and these do have write permission. Many 
commands, such as ps, top, lsmod, vmstat, and others, retrieve their 
data from /proc. This approach avoids the proliferation of system calls, 
by using VFS and pseudo filesystems.

Bill Anderson
WW7BA
--
To unsubscribe, e-mail: opensuse+unsubscribe@xxxxxxxxxxxx
For additional commands, e-mail: opensuse+help@xxxxxxxxxxxx