From: Peter Zijlstra <peterz@infradead.org>
To: "Michal Koutný" <mkoutny@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
mm-commits@vger.kernel.org, yu.c.chen@intel.com,
vineethr@linux.ibm.com, venkat88@linux.ibm.com, tj@kernel.org,
tim.c.chen@intel.com, shakeel.butt@linux.dev,
roman.gushchin@linux.dev, muchun.song@linux.dev,
mingo@redhat.com, mhocko@kernel.org, mgorman@suse.de,
kprateek.nayak@amd.com, hannes@cmpxchg.org, corbet@lwn.net,
Ayush.jain3@amd.com, aubrey.li@intel.com, libo.chen@oracle.com
Subject: Re: [merged mm-stable] sched-numa-fix-task-swap-by-skipping-kernel-threads.patch removed from -mm tree
Date: Thu, 22 May 2025 10:23:32 +0200 [thread overview]
Message-ID: <20250522082332.GH24938@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <yf637jkmcdunhgs6qjbnprygpkifnphdcqofp546dd6ti6s6i4@b2geqedevt42>
On Thu, May 22, 2025 at 10:19:29AM +0200, Michal Koutný wrote:
> On Wed, May 21, 2025 at 09:11:14PM +0200, Peter Zijlstra <peterz@infradead.org> wrote:
> > > @@ -2273,7 +2273,8 @@ static bool task_numa_compare(struct tas
> > >
> > > rcu_read_lock();
> > > cur = rcu_dereference(dst_rq->curr);
> > > - if (cur && ((cur->flags & PF_EXITING) || is_idle_task(cur)))
> > > + if (cur && ((cur->flags & PF_EXITING) || is_idle_task(cur) ||
> > > + !cur->mm))
> >
> > !->mm is not the right way to determine a kernel thread, PF_KTHREAD is.
> > Notably, there are kernel threads that have ->mm.
>
> How does this compose with the NUMA balancing? Should kernel threads
> with ->mm be considered here? (I don't know thus asking.)
I don't know either -- I've not thought about it, I just reacted to the
difference in changelog/comment and code.
Typically the kthreads with mm are io-uring threads. And I just don't
know enough about those.
next prev parent reply other threads:[~2025-05-22 8:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-21 16:56 [merged mm-stable] sched-numa-fix-task-swap-by-skipping-kernel-threads.patch removed from -mm tree Andrew Morton
2025-05-21 19:11 ` Peter Zijlstra
2025-05-21 20:58 ` Andrew Morton
2025-05-22 6:31 ` K Prateek Nayak
2025-05-22 10:01 ` Libo Chen
2025-05-22 21:56 ` Andrew Morton
2025-05-23 7:48 ` Chen, Yu C
2025-05-22 8:19 ` Michal Koutný
2025-05-22 8:23 ` Peter Zijlstra [this message]
2025-05-22 8:36 ` Libo Chen
2025-05-23 5:09 ` Chen, Yu C
2025-05-23 8:21 ` Libo Chen
-- strict thread matches above, loose matches on Subject: below --
2025-06-01 5:47 Andrew Morton
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