From: Peter Zijlstra <peterz@infradead.org>
To: Andrea Righi <arighi@nvidia.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>,
Tejun Heo <tj@kernel.org>, David Vernet <void@manifault.com>,
Changwoo Min <changwoo@igalia.com>,
Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Valentin Schneider <vschneid@redhat.com>,
Vladimir Vdovin <deliran@verdict.gg>,
Gregory Price <gourry@gourry.net>,
David Dai <david.dai@linux.dev>, Emil Tsalapatis <etsal@meta.com>,
Christian Loehle <christian.loehle@arm.com>,
Balbir Singh <balbirs@nvidia.com>,
Lee Trager <ltrager@nvidia.com>,
sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/6] sched_ext: Add a kfunc to read a task's preferred NUMA node
Date: Tue, 27 Oct 2026 12:54:10 +0100 [thread overview]
Message-ID: <20261027115410.GK2668564@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <auCJHU4_ugxayy7i@gpd4>
On Tue, Oct 27, 2026 at 12:21:01PM +0100, Andrea Righi wrote:
> > But should we not cleanup first and then add shiny on top?
>
> Fair enough. Looking more closely, I think there're only two places in
> fair that still use p->numa_preferred_nid when NUMA balancing is
> disabled at runtime: find_idlest_group() and the fbq classification in
> the load balancer (via rq->nr_numa_running / nr_preferred_running).
> Everything else is already gated by sched_numa_balancing.
>
> Assuming I'm not missing anything, we can probably add a preparatory
> patch that gates those two on sched_numa_balancing as well, then make
> scx_bpf_task_numa_nid() return NUMA_NO_NODE when NUMA balancing is
> disabled. In this way the stale value is never used.
Sounds like a plan :-)
next prev parent reply other threads:[~2026-10-27 11:54 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-27 4:13 [PATCHSET v2 sched_ext/for-7.5] sched_ext: Add NUMA balancing support Andrea Righi
2026-10-27 4:13 ` [PATCH 1/6] sched/numa: Let other scheduling classes drive NUMA scanning Andrea Righi
2026-10-27 4:13 ` [PATCH 2/6] sched/numa: Leave the placement of a BPF-scheduled task to its scheduler Andrea Righi
2026-10-27 5:45 ` K Prateek Nayak
2026-10-27 6:43 ` Andrea Righi
2026-10-27 9:00 ` K Prateek Nayak
2026-10-27 9:30 ` Andrea Righi
2026-10-27 10:43 ` Peter Zijlstra
2026-10-27 11:09 ` Andrea Righi
2026-10-27 11:52 ` Peter Zijlstra
2026-10-27 4:13 ` [PATCH 3/6] sched/numa: Notify the scheduling class of preferred node changes Andrea Righi
2026-10-27 5:30 ` K Prateek Nayak
2026-10-27 6:34 ` Andrea Righi
2026-10-27 8:02 ` K Prateek Nayak
2026-10-27 4:13 ` [PATCH 4/6] sched_ext: Report preferred NUMA nodes through ops.set_numa_node() Andrea Righi
2026-10-27 10:49 ` Peter Zijlstra
2026-10-27 11:14 ` Andrea Righi
2026-10-27 4:13 ` [PATCH 5/6] sched_ext: Add a kfunc to read a task's preferred NUMA node Andrea Righi
2026-10-27 6:12 ` K Prateek Nayak
2026-10-27 6:57 ` Andrea Righi
2026-10-27 10:50 ` Peter Zijlstra
2026-10-27 11:21 ` Andrea Righi
2026-10-27 11:54 ` Peter Zijlstra [this message]
2026-10-27 4:13 ` [PATCH 6/6] selftests/sched_ext: Test preferred NUMA node notifications Andrea Righi
2026-10-27 10:52 ` [PATCHSET v2 sched_ext/for-7.5] sched_ext: Add NUMA balancing support Peter Zijlstra
2026-10-27 11:38 ` Andrea Righi
2026-10-27 11:55 ` Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20261027115410.GK2668564@noisy.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=arighi@nvidia.com \
--cc=balbirs@nvidia.com \
--cc=bsegall@google.com \
--cc=changwoo@igalia.com \
--cc=christian.loehle@arm.com \
--cc=david.dai@linux.dev \
--cc=deliran@verdict.gg \
--cc=dietmar.eggemann@arm.com \
--cc=etsal@meta.com \
--cc=gourry@gourry.net \
--cc=juri.lelli@redhat.com \
--cc=kprateek.nayak@amd.com \
--cc=linux-kernel@vger.kernel.org \
--cc=ltrager@nvidia.com \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=rostedt@goodmis.org \
--cc=sched-ext@lists.linux.dev \
--cc=tj@kernel.org \
--cc=vincent.guittot@linaro.org \
--cc=void@manifault.com \
--cc=vschneid@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.