lkml.org 
[lkml]   [2007]   [Oct]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Reserve N process to root
El Fri, 12 Oct 2007 09:29:10 +0300
Al Boldi <a1426z@gawab.com> escribió:

> Kyle Moffett wrote:
> > On Oct 12, 2007, at 01:37:23, Al Boldi wrote:
> > > You have a point, and resource-controllers can probably control
> > > DoS a lot better, but the they also incur more overhead. Think
> > > of this "lockout prevention" patch as a near zero overhead safety
> > > valve.
> >
> > But why do you need to add "lockout prevention" if it already
> > exists?
>
> I said this before, but I'll say it again: it's about overhead!
>
> > With CFS' extremely efficient per-user-scheduling (hopefully
> > soon to be the default) there are only two forms of lockout by non-
> > root processes: (1) Running out of PIDs in the box's PID-space
> > (think tens or hundreds of thousands of processes), or (2) Swap-
> > storming the box to death. To put it bluntly trying to reserve free
> > PID slots is attacking the wrong end of the problem and your so
> > called "lockout prevention" could very easily ensure that 10 PIDs
> > are available even if the user has swapstormed the box with the
> > PIDs he does have.
>
> I think you are reading this wrong. It's not about reserving PIDs,
> it's about exceeding the max-threads limit. This limit is global and
> affects every user including root, which is good, as this allows the
> sysadmin to fence the system into a controllable state. So once the
> system reaches the fence, sysadmin-intervention allows root to exceed
> the fence.
>
> Again, this is much nicer with real resource-controllers, but again
> it's also more overhead.

Just an _if()_ ?

may be enable it as an option in kernel config ?

>
> Thanks!
>
> --
> Al
>
> -
> To unsubscribe from this list: send the line "unsubscribe
> linux-kernel" in the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/


--
Gustavo Chaín Dumit
Alumno de Ingeniería de Ejecución Informática
Pontificia Universidad Católica de Valparaiso
http://aleph.homeunix.com/~gchain
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-10-13 03:39    [W:0.083 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site