Re: [PATCH] oom_pardon, aka don't kill my xlock

[Herbert Poetzl <herbert@13thfloor.at>]

On Mon, Sep 27, 2004 at 01:42:19PM -0300, Marcelo Tosatti wrote:
> On Mon, Sep 27, 2004 at 07:12:53PM +0200, Herbert Poetzl wrote:
> > On Mon, Sep 27, 2004 at 10:35:54AM -0300, Marcelo Tosatti wrote:
> > > On Mon, Sep 27, 2004 at 02:12:26PM +0100, Jon Masters wrote:
> > > > Hi all,
> > > > 
> > > > Just out of interest then...suppose we've got a loopback swap device
> > > > and that we can extend this by creating a new file or extending
> > > > somehow the existing one.
> > > > 
> > > > What would be wrong with having the page reclaim algorithms use one of
> > > > the low memory watermarks as a trigger to call in to userspace to
> > > > extend the swap available if possible? This is probably what Microsoft
> > > > et al do with their "Windows is extending your virtual memory, yada
> > > > yada blah blah". Comments? Already done?
> > > 
> > > You dont to change kernel code for that - make a script to monitor 
> > > swap usage, as soon as it gets below a given watermark, you swapon 
> > > whatever swapfile you want.
> > 
> > hmm, sounds good, but what if next 'burst' of
> > swapped out data is larger than the watermark?
> 
> Give the watermark a large enough value.

right, probably setting it to the currently 
available swapspace solves that issue ;)

anyway as I said, I'm fine with 'does not
work' but not very happy with half-assed
userspace solutions ...

best,
Herbert

> > I'm no friend of the 'extend swap idea' so don't
> > get me wrong, but userspace can just reduce the
> > cases where you get out-of-swap, without support
> > from the kernel side (via some userspace helper).
> 
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