Re: User space out of memory approach

Mauricio Lin
2005-01-28T13:58:35Z

Hi Andrea,

On Thu, 27 Jan 2005 23:11:29 +0100, Andrea Arcangeli <andrea@suse.de> wrote:
> On Thu, Jan 27, 2005 at 02:54:13PM -0400, Mauricio Lin wrote:
> > Hi Andrea,
> >
> > On Wed, 26 Jan 2005 01:49:01 +0100, Andrea Arcangeli <andrea@suse.de> wrote:
> > > On Tue, Jan 25, 2005 at 08:11:19PM -0400, Mauricio Lin wrote:
> > > > Sometimes the first application to be killed is XFree. AFAIK the
> > >
> > > This makes more sense now. You need somebody trapping sigterm in order
> > > to lockup and X sure traps it to recover the text console.
> > >
> > > Can you replace this:
> > >
> > > if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_RAWIO)) {
> > > force_sig(SIGTERM, p);
> > > } else {
> > > force_sig(SIGKILL, p);
> > > }
> > >
> > > with this?
> > >
> > > force_sig(SIGKILL, p);
> > >
> > > in mm/oom_kill.c.
> >
> > Nice. Your suggestion made the error goes away.
> >
> > We are still testing in order to compare between your OOM Killer and
> > Original OOM Killer.
>
> Ok, thanks for the confirmation. So my theory was right.
>
> Basically we've to make this patch, now that you already edited the
> code, can you diff and send a patch that will be the 6/5 in the serie?

OK. I will send the patch.

> (then after fixing this last very longstanding [now deadlock prone too]
> bug, we can think how to make at a 7/5 that will wait a few seconds
> after sending a sigterm, to fallback into a sigkill, that shouldn't be
> difficult, but the above 6/5 will already make the code correct)
>
> Note, if you add swap it'll workaround it too since then the memhog will
> be allowed to grow to a larger rss than X. With 128m of ram and no swap,
> X is one of the biggest with xshm involved from some client app
> allocating lots of pictures. I could never notice since I always tested
> it either with swap or on higher mem systems and my test box runs
> with an idle X too which isn't that big ;).

Well, we like to reduce the memory resources, because we also think
about OOM Killer in small devices with few resources.

BR,

Mauricio Lin.