Re: [PATCH v2] sched/isolation: Make use of more than one housekeeping cpu

[Waiman Long]

On 3/5/25 12:14 PM, Phil Auld wrote:
> On Tue, Mar 04, 2025 at 02:24:19PM +0100 Frederic Weisbecker wrote:
> > Le Tue, Feb 18, 2025 at 06:46:18PM +0000, Phil Auld a écrit :
> > > The exising code uses housekeeping_any_cpu() to select a cpu for
> > > a given housekeeping task. However, this often ends up calling
> > > cpumask_any_and() which is defined as cpumask_first_and() which has
> > > the effect of alyways using the first cpu among those available.
> > >
> > > The same applies when multiple NUMA nodes are involved. In that
> > > case the first cpu in the local node is chosen which does provide
> > > a bit of spreading but with multiple HK cpus per node the same
> > > issues arise.
> > >
> > > We have numerous cases where a single HK cpu just cannot keep up
> > > and the remote_tick warning fires. It also can lead to the other
> > > things (orchastration sw, HA keepalives etc) on the HK cpus getting
> > > starved which leads to other issues.  In these cases we recommend
> > > increasing the number of HK cpus.  But... that only helps the
> > > userspace tasks somewhat. It does not help the actual housekeeping
> > > part.
> > >
> > > Spread the HK work out by having housekeeping_any_cpu() and
> > > sched_numa_find_closest() use cpumask_any_and_distribute()
> > > instead of cpumask_any_and().
> > >
> > > Signed-off-by: Phil Auld <pauld@xxxxxxxxxx>
> > > Reviewed-by: Waiman Long <longman@xxxxxxxxxx>
> > > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > > Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
> > > Cc: Frederic Weisbecker <frederic@xxxxxxxxxx>
> > > Cc: Waiman Long <longman@xxxxxxxxxx>
> > > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > > Link: https://lore.kernel.org/lkml/20250211141437.GA349314@xxxxxxxxxxxxxxxxxx/
> > Acked-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
> Thanks Frederic!
>
> Anyone with commit powers willing to pick this up?

Is this patch eligible to be merged into sched/core for the current 
cycle or will have to wait until the next one?

Thanks,
Longman