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Miller" , Eric Dumazet , Gabriele Monaco , Greg Kroah-Hartman , Ingo Molnar , Jakub Kicinski , Jens Axboe , Johannes Weiner , Lai Jiangshan , Marco Crivellari , Michal Hocko , Muchun Song , Paolo Abeni , Peter Zijlstra , Phil Auld , "Rafael J . Wysocki" , Roman Gushchin , Shakeel Butt , Simon Horman , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , Will Deacon , cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH 16/33] PCI: Flush PCI probe workqueue on cpuset isolated partition change Date: Mon, 13 Oct 2025 22:31:29 +0200 Message-ID: <20251013203146.10162-17-frederic@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013203146.10162-1-frederic@kernel.org> References: <20251013203146.10162-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: rtrzufwz3nttj57zztmp1mjtydhr5gqz X-Rspamd-Queue-Id: A2B7880010 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1760387645-727861 X-HE-Meta: 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 2Bs6X2kT U4vLh+T8BY6H61nNyk1BNunqEd6QpACpq6aIOPgOHcMoC4Pb2EMFqjBGt9edyL2zPvsZd+EuBjy0r4a4d7nPpUjmdCSFylbmrivhhpax6Kt626mzVVxLej+jxHDhHW8LUcO14BqDIaqMKk9KVdPLPVdhDJRuEywiBRqd6m6Hk8FCQdD/C23PMVOm4KXV1hy2EUtKbaFHBgvBRKpjB8UH91sx1e794nbhitZ6JafF3fq+SPsh/m8MtACMix49oxbeBFmn8nKeYt7Ospok= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The HK_TYPE_DOMAIN housekeeping cpumask is now modifyable at runtime. In order to synchronize against PCI probe works and make sure that no asynchronous probing is still pending or executing on a newly made isolated CPU, the housekeeping susbsystem must flush the PCI probe works. However the PCI probe works can't be flushed easily since they are queued to the main per-CPU workqueue pool. Solve this with creating a PCI probe specific pool and provide and use the appropriate flushing API. Signed-off-by: Frederic Weisbecker --- drivers/pci/pci-driver.c | 17 ++++++++++++++++- include/linux/pci.h | 3 +++ kernel/sched/isolation.c | 2 ++ 3 files changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 7b74d22b20f7..ac86aaec8bcf 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -337,6 +337,8 @@ static int local_pci_probe(struct drv_dev_and_id *ddi) return 0; } +static struct workqueue_struct *pci_probe_wq; + struct pci_probe_arg { struct drv_dev_and_id *ddi; struct work_struct work; @@ -407,7 +409,11 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev, cpu = cpumask_any_and(cpumask_of_node(node), wq_domain_mask); if (cpu < nr_cpu_ids) { - schedule_work_on(cpu, &arg.work); + struct workqueue_struct *wq = pci_probe_wq; + + if (WARN_ON_ONCE(!wq)) + wq = system_percpu_wq; + queue_work_on(cpu, wq, &arg.work); rcu_read_unlock(); flush_work(&arg.work); error = arg.ret; @@ -425,6 +431,11 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev, return error; } +void pci_probe_flush_workqueue(void) +{ + flush_workqueue(pci_probe_wq); +} + /** * __pci_device_probe - check if a driver wants to claim a specific PCI device * @drv: driver to call to check if it wants the PCI device @@ -1760,6 +1771,10 @@ static int __init pci_driver_init(void) { int ret; + pci_probe_wq = alloc_workqueue("sync_wq", WQ_PERCPU, 0); + if (!pci_probe_wq) + return -ENOMEM; + ret = bus_register(&pci_bus_type); if (ret) return ret; diff --git a/include/linux/pci.h b/include/linux/pci.h index d1fdf81fbe1e..3281c235b895 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1175,6 +1175,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, struct pci_ops *ops, void *sysdata, struct list_head *resources); int pci_host_probe(struct pci_host_bridge *bridge); +void pci_probe_flush_workqueue(void); int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax); int pci_bus_update_busn_res_end(struct pci_bus *b, int busmax); void pci_bus_release_busn_res(struct pci_bus *b); @@ -2037,6 +2038,8 @@ static inline int pci_has_flag(int flag) { return 0; } _PCI_NOP_ALL(read, *) _PCI_NOP_ALL(write,) +static inline void pci_probe_flush_workqueue(void) { } + static inline struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from) diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 5cd3d98a2663..b1eea5440484 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -8,6 +8,7 @@ * */ #include +#include #include "sched.h" enum hk_flags { @@ -144,6 +145,7 @@ int housekeeping_update(struct cpumask *mask, enum hk_type type) synchronize_rcu(); + pci_probe_flush_workqueue(); mem_cgroup_flush_workqueue(); vmstat_flush_workqueue(); -- 2.51.0