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List:       linux-ha-dev
Subject:    Re: [Linux-ha-dev] Fwd: [Pacemaker] Resource Scheduler Parameters
From:       Dejan Muhamedagic <dejanmm () fastmail ! fm>
Date:       2009-04-09 13:48:21
Message-ID: 20090409134820.GA10280 () rondo ! homenet
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Hi,

On Thu, Apr 09, 2009 at 07:00:07AM -0500, btinsley wrote:
> Sorry this got off a mailing list. Below is a proposed patch for handling an
> issue where lrmd spawns all cluster resources with the realtime scheduler
> class (SCHED_RR) set. I know on Linux that the default is SCHED_OTHER and
> the code in the patch below is POSIX compliant, so hopefully it will not
> cause issues for folks on other OSes.

Applied. Thanks.

Dejan

P.S. Forgot to set you as the author of the patch, sorry about that :(

> 
> 
> ---------- Forwarded message ----------
> From: Andrew Beekhof <beekhof@gmail.com>
> Date: Thu, Apr 9, 2009 at 1:57 AM
> Subject: Re: [Pacemaker] Resource Scheduler Parameters
> To: btinsley <btinsley@gmail.com>
> 
> 
> dejan maintains the lrmd, you'd better send this to the heartbeat
> mailing list (but it looks fine to me)
> 
> On Thu, Apr 9, 2009 at 01:42, btinsley <btinsley@gmail.com> wrote:
> > Nevermind, I think I found it... in the heartbeat source. Forgot about
> that,
> > but grep-ing Pacemaker code for fork/exec/clone code freaked me out for a
> > little while ;-)
> >
> > If you want it, this patch should do the trick. It's POSIX compliant, so
> > hopefully it won't be troublesome on other OSes ;-)  If I missed the mark
> > completely here, the code can be placed wherever it's needed.
> >
> >
> > --- lrmd.c.orig 2009-04-08 15:33:04.038843903 -0500
> > +++ lrmd.c      2009-04-08 15:45:11.976099804 -0500
> > @@ -34,6 +34,7 @@
> >  #include <dirent.h>
> >  #include <pwd.h>
> >  #include <time.h>
> > +#include <sched.h>
> >
> >  #include <glib.h>
> >  #include <heartbeat.h>
> > @@ -3087,6 +3088,15 @@
> >                         return HA_OK;
> >
> >                 case 0:         /* Child */
> > +                       if (sched_getscheduler(0) != SCHED_OTHER) {
> > +                               lrmd_debug2(LOG_DEBUG,
> > +                                       "perform_ra_op: resetting
> scheduler
> > class to SCHED_OTHER");
> > +                               struct sched_param sp;
> > +                               sp.sched_priority = 0;
> > +                               if (sched_setscheduler(0, SCHED_OTHER,
> &sp)
> > == -1)
> > +                                       cl_perror("%s::%d:
> > sched_setscheduler",
> > +                                               __FUNCTION__, __LINE__);
> > +                       }
> >                         /* Man: The call setpgrp() is equivalent to
> > setpgid(0,0)
> >                          * _and_ compiles on BSD variants too
> >                          * need to investigate if it works the same too.
> >
> >
> >
> > On Wed, Apr 8, 2009 at 1:28 PM, btinsley <btinsley@gmail.com> wrote:
> >>
> >> Where in the code are resources spawned? Is it start_subsystem() or
> >> elsewhere? I'll be glad to pitch in and offer a patch if you want.
> >>
> >>
> >>
> >> On Wed, Apr 8, 2009 at 1:18 PM, Andrew Beekhof <beekhof@gmail.com> wrote:
> >>>
> >>> On Wed, Apr 8, 2009 at 18:40, btinsley <btinsley@gmail.com> wrote:
> >>> > AIS guys said to upgrade to the latest Whitetank :-)  I did and the
> >>> > behavior
> >>> > is the same, but it's not necessarily incorrect. The aisexec process
> >>> > sets
> >>> > itself to the realtime scheduling class, which does the same for all
> of
> >>> > the
> >>> > Pacemaker processes when they are spawned. This is probably how you
> >>> > want the
> >>> > cluster daemons to run. However, when lrmd spawns resource scripts
> >>> > *everything* the script does also inherits the realtime scheduling
> >>> > class.
> >>> > I'm not sure this is how you want all your clustered applications
> >>> > running
> >>> > (or all the other stuff a resource script may do). Thoughts here?
> >>>
> >>> I'd tend to agree with you - the lrmd should probably do the
> >>> equivalent of chrt for the child processes it uses to perform the
> >>> resource actions
> >>>
> >>> > As a workaround, I added calls to the chrt program in each resource
> >>> > script
> >>> > to "downgrade" the scheduler to SCHED_OTHER and set the priority to
> >>> > zero,
> >>> > which is the system default.
> >>>
> >>> _______________________________________________
> >>> Pacemaker mailing list
> >>> Pacemaker@oss.clusterlabs.org
> >>> http://oss.clusterlabs.org/mailman/listinfo/pacemaker
> >>
> >
> >

> _______________________________________________________
> Linux-HA-Dev: Linux-HA-Dev@lists.linux-ha.org
> http://lists.linux-ha.org/mailman/listinfo/linux-ha-dev
> Home Page: http://linux-ha.org/

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