linux-kernel - Re: [PATCH 19/33] cpuset: Propagate cpuset isolation update to timers through housekeeping

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aVVG3-NBYIhJmVsk@localhost.localdomain>
Date: Wed, 31 Dec 2025 16:53:03 +0100
From: Frederic Weisbecker <frederic@...nel.org>
To: Waiman Long <llong@...hat.com>
Cc: LKML <linux-kernel@...r.kernel.org>,
	Michal Koutný <mkoutny@...e.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Chen Ridong <chenridong@...wei.com>,
	Danilo Krummrich <dakr@...nel.org>,
	"David S . Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Gabriele Monaco <gmonaco@...hat.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Ingo Molnar <mingo@...hat.com>, Jakub Kicinski <kuba@...nel.org>,
	Jens Axboe <axboe@...nel.dk>, Johannes Weiner <hannes@...xchg.org>,
	Lai Jiangshan <jiangshanlai@...il.com>,
	Marco Crivellari <marco.crivellari@...e.com>,
	Michal Hocko <mhocko@...e.com>, Muchun Song <muchun.song@...ux.dev>,
	Paolo Abeni <pabeni@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>, Phil Auld <pauld@...hat.com>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	Roman Gushchin <roman.gushchin@...ux.dev>,
	Shakeel Butt <shakeel.butt@...ux.dev>,
	Simon Horman <horms@...nel.org>, Tejun Heo <tj@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Vlastimil Babka <vbabka@...e.cz>, Will Deacon <will@...nel.org>,
	cgroups@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-block@...r.kernel.org, linux-mm@...ck.org,
	linux-pci@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH 19/33] cpuset: Propagate cpuset isolation update to
 timers through housekeeping

Le Fri, Dec 26, 2025 at 03:40:25PM -0500, Waiman Long a écrit :
> On 12/24/25 8:45 AM, Frederic Weisbecker wrote:
> > Until now, cpuset would propagate isolated partition changes to
> > timer migration so that unbound timers don't get migrated to isolated
> > CPUs.
> > 
> > Since housekeeping now centralizes, synchronize and propagates isolation
> > cpumask changes, perform the work from that subsystem for consolidation
> > and consistency purposes.
> > 
> > Signed-off-by: Frederic Weisbecker<frederic@...nel.org>
> > ---
> >   kernel/cgroup/cpuset.c   | 3 ---
> >   kernel/sched/isolation.c | 5 +++++
> >   2 files changed, 5 insertions(+), 3 deletions(-)
> > 
> > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> > index a492d23dd622..25ac6c98113c 100644
> > --- a/kernel/cgroup/cpuset.c
> > +++ b/kernel/cgroup/cpuset.c
> > @@ -1487,9 +1487,6 @@ static void update_isolation_cpumasks(void)
> >   	ret = housekeeping_update(isolated_cpus, HK_TYPE_DOMAIN);
> >   	WARN_ON_ONCE(ret < 0);
> > -	ret = tmigr_isolated_exclude_cpumask(isolated_cpus);
> > -	WARN_ON_ONCE(ret < 0);
> > -
> >   	isolated_cpus_updating = false;
> >   }
> > diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
> > index d224bca299ed..84a257d05918 100644
> > --- a/kernel/sched/isolation.c
> > +++ b/kernel/sched/isolation.c
> > @@ -150,7 +150,12 @@ int housekeeping_update(struct cpumask *isol_mask, enum hk_type type)
> >   	pci_probe_flush_workqueue();
> >   	mem_cgroup_flush_workqueue();
> >   	vmstat_flush_workqueue();
> > +
> >   	err = workqueue_unbound_housekeeping_update(housekeeping_cpumask(type));
> > +	WARN_ON_ONCE(err < 0);
> > +
> > +	err = tmigr_isolated_exclude_cpumask(isol_mask);
> > +	WARN_ON_ONCE(err < 0);
> >   	kfree(old);
> 
> If you are doing "WARN_ON_ONCE() in housekeeping_update(), you don't need to
> do it in update_isolation_cpumask() to avoid double warnings. Actually, you
> don't need to return an error code from housekeeping_update() at all.
> 
> Cheers, Longman

Ok, I'm keeping the error return for allocation failures at the beginning of
housekeeping_update() but the rest will only warn in place.

Thanks.

-- 
Frederic Weisbecker
SUSE Labs