| 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
| ||
|
Message-ID: <a9aa92b5-5e5a-4e9f-bfa3-31033d190457@redhat.com>
Date: Fri, 26 Dec 2025 15:31:26 -0500
From: Waiman Long <llong@...hat.com>
To: Frederic Weisbecker <frederic@...nel.org>,
LKML <linux-kernel@...r.kernel.org>
Cc: 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 18/33] cpuset: Propagate cpuset isolation update to
workqueue through housekeeping
On 12/24/25 8:45 AM, Frederic Weisbecker wrote:
> Until now, cpuset would propagate isolated partition changes to
> workqueues so that unbound workers get properly reaffined.
>
> Since housekeeping now centralizes, synchronize and propagates isolation
> cpumask changes, perform the work from that subsystem for consolidation
> and consistency purposes.
>
> For simplification purpose, the target function is adapted to take the
> new housekeeping mask instead of the isolated mask.
>
> Suggested-by: Tejun Heo <tj@...nel.org>
> Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
> ---
> include/linux/workqueue.h | 2 +-
> init/Kconfig | 1 +
> kernel/cgroup/cpuset.c | 9 +++------
> kernel/sched/isolation.c | 4 +++-
> kernel/workqueue.c | 17 ++++++++++-------
> 5 files changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
> index dabc351cc127..a4749f56398f 100644
> --- a/include/linux/workqueue.h
> +++ b/include/linux/workqueue.h
> @@ -588,7 +588,7 @@ struct workqueue_attrs *alloc_workqueue_attrs_noprof(void);
> void free_workqueue_attrs(struct workqueue_attrs *attrs);
> int apply_workqueue_attrs(struct workqueue_struct *wq,
> const struct workqueue_attrs *attrs);
> -extern int workqueue_unbound_exclude_cpumask(cpumask_var_t cpumask);
> +extern int workqueue_unbound_housekeeping_update(const struct cpumask *hk);
>
> extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
> struct work_struct *work);
> diff --git a/init/Kconfig b/init/Kconfig
> index fa79feb8fe57..518830fb812f 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1254,6 +1254,7 @@ config CPUSETS
> bool "Cpuset controller"
> depends on SMP
> select UNION_FIND
> + select CPU_ISOLATION
> help
> This option will let you create and manage CPUSETs which
> allow dynamically partitioning a system into sets of CPUs and
> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> index e13e32491ebf..a492d23dd622 100644
> --- a/kernel/cgroup/cpuset.c
> +++ b/kernel/cgroup/cpuset.c
> @@ -1484,15 +1484,12 @@ static void update_isolation_cpumasks(void)
>
> lockdep_assert_cpus_held();
>
> - ret = workqueue_unbound_exclude_cpumask(isolated_cpus);
> - WARN_ON_ONCE(ret < 0);
> -
> - ret = tmigr_isolated_exclude_cpumask(isolated_cpus);
> - WARN_ON_ONCE(ret < 0);
> -
> 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 7dbe037ea8df..d224bca299ed 100644
> --- a/kernel/sched/isolation.c
> +++ b/kernel/sched/isolation.c
> @@ -121,6 +121,7 @@ EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
> int housekeeping_update(struct cpumask *isol_mask, enum hk_type type)
> {
> struct cpumask *trial, *old = NULL;
> + int err;
>
> if (type != HK_TYPE_DOMAIN)
> return -ENOTSUPP;
> @@ -149,10 +150,11 @@ 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));
>
> kfree(old);
>
> - return 0;
> + return err;
> }
>
> void __init housekeeping_init(void)
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 253311af47c6..eb5660013222 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -6959,13 +6959,16 @@ static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask)
> }
>
> /**
> - * workqueue_unbound_exclude_cpumask - Exclude given CPUs from unbound cpumask
> - * @exclude_cpumask: the cpumask to be excluded from wq_unbound_cpumask
> + * workqueue_unbound_housekeeping_update - Propagate housekeeping cpumask update
> + * @hk: the new housekeeping cpumask
> *
> - * This function can be called from cpuset code to provide a set of isolated
> - * CPUs that should be excluded from wq_unbound_cpumask.
> + * Update the unbound workqueue cpumask on top of the new housekeeping cpumask such
> + * that the effective unbound affinity is the intersection of the new housekeeping
> + * with the requested affinity set via nohz_full=/isolcpus= or sysfs.
> + *
> + * Return: 0 on success and -errno on failure.
> */
> -int workqueue_unbound_exclude_cpumask(cpumask_var_t exclude_cpumask)
> +int workqueue_unbound_housekeeping_update(const struct cpumask *hk)
> {
> cpumask_var_t cpumask;
> int ret = 0;
> @@ -6981,14 +6984,14 @@ int workqueue_unbound_exclude_cpumask(cpumask_var_t exclude_cpumask)
> * (HK_TYPE_WQ ∩ HK_TYPE_DOMAIN) house keeping mask and rewritten
> * by any subsequent write to workqueue/cpumask sysfs file.
> */
> - if (!cpumask_andnot(cpumask, wq_requested_unbound_cpumask, exclude_cpumask))
> + if (!cpumask_and(cpumask, wq_requested_unbound_cpumask, hk))
> cpumask_copy(cpumask, wq_requested_unbound_cpumask);
> if (!cpumask_equal(cpumask, wq_unbound_cpumask))
> ret = workqueue_apply_unbound_cpumask(cpumask);
>
> /* Save the current isolated cpumask & export it via sysfs */
> if (!ret)
> - cpumask_copy(wq_isolated_cpumask, exclude_cpumask);
> + cpumask_andnot(wq_isolated_cpumask, cpu_possible_mask, hk);
>
> mutex_unlock(&wq_pool_mutex);
> free_cpumask_var(cpumask);
Reviewed-by: Waiman Long <longman@...hat.com>
Powered by blists - more mailing lists