From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7C54BD3EE8A for ; Thu, 22 Jan 2026 16:14:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DE8C46B026D; Thu, 22 Jan 2026 11:14:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D964E6B027C; Thu, 22 Jan 2026 11:14:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C95B36B0281; Thu, 22 Jan 2026 11:14:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id B7D3E6B026D for ; Thu, 22 Jan 2026 11:14:40 -0500 (EST) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 9CF3458E69 for ; Thu, 22 Jan 2026 16:14:39 +0000 (UTC) X-FDA: 84360097878.08.24AFBC8 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf04.hostedemail.com (Postfix) with ESMTP id D6F0C40014 for ; Thu, 22 Jan 2026 16:14:37 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=hpSHO+gh; spf=pass (imf04.hostedemail.com: domain of helgaas@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=helgaas@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1769098478; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:dkim-signature; bh=9aRzvjV+Wif6zegr+a6nCLd0Tck/+9rU+CVjUc1JMr0=; b=lux6qzX2GlumRHU5Spaym/9S5nTPYMJvOhk/2rFXuQyaZKZblQzZagnbfxfDHh4gufXU8U QAjxYIrzKH3gbt2xFe/Q8h70PpIOzQ2l5UUTvzAs9N1qeTlKxtxiIe99SQMPZ7Hywo331q GCxTXjgHRZ1uzACu/mWUV8KWLBh6mug= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=hpSHO+gh; spf=pass (imf04.hostedemail.com: domain of helgaas@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=helgaas@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1769098478; a=rsa-sha256; cv=none; b=3I+hnsWIKDVxxIifkr/echORHCA+N4mWCqaYO/W1hzb4S4xv8MxTDn9F+HvP72Ucjbb0m/ e86lSJfA3EZVoRm620Z0xwOBVPARgnDVrSHGykpGvNgRm8bPxJUHLIYkQVSL9FS/QkjO8+ SxxVBtwzVNKQn4Glndu/FBLLJ4enzzk= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id DDFE441B6E; Thu, 22 Jan 2026 16:14:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 911A5C116C6; Thu, 22 Jan 2026 16:14:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769098476; bh=GrBl0GmB4EskXynUW6bH8pp7knC2vNONOphZtdopzwU=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=hpSHO+ghl6+V/2A9sZcw97dKURkfaqnoh6fz57v7b/GtWXdfzXyy1Yby0UyhDjKvn 2W+GC9cq47CPQ+TyiGLDn45Swl8siTnsyFJ7on/xxPH49i5KT8MfQ3vmfWawrqtvS/ e0XgagEPSQy8S8MSzhOzpR/YURn2bktJ0b47/jNeBbGfV3QYbH+giEwsut0bvtVELK rpWCghXqtrEljSmHQ2BL3Elb1FNkrsKZfXYGCYyUHca2y5JEbBVE6ebqtSPa8N/6sE xvWIAneDy9J19bcgL4eE88SS3YXNHupckNIR5dM3vOtcnyqIgrEjM/GhgZcu+RgECE P9HBLzh+xmLPQ== Date: Thu, 22 Jan 2026 10:14:35 -0600 From: Bjorn Helgaas To: Frederic Weisbecker Cc: LKML , Michal =?utf-8?Q?Koutn=C3=BD?= , Andrew Morton , Bjorn Helgaas , Catalin Marinas , Chen Ridong , Danilo Krummrich , "David S . 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: Re: [PATCH 17/33] PCI: Flush PCI probe workqueue on cpuset isolated partition change Message-ID: <20260122161435.GA1250260@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260101221359.22298-18-frederic@kernel.org> X-Rspam-User: X-Rspamd-Queue-Id: D6F0C40014 X-Rspamd-Server: rspam07 X-Stat-Signature: g3bsrh7gt14zcbmzy8ccdatk6zc5w4k6 X-HE-Tag: 1769098477-990494 X-HE-Meta: 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 EQJISUgG R23E1bGDJtzxoDab1eB53EqRdhcQcvRTdvRoeH+zPmetpc+rxxIyMpfYXhdFKaFFAoOdf8BmLr1iOMKoISjso26I2HBxdU0z6GNpsWPZsRVR12uIGqoCzaLmCV6rcH4XWNJ9m+YNeHXwhlvdOMMoKKj82PrSbDHxgNj5ZI7my7a7disHy80YXtSVMYHnVcc8jY1s2FgIFfEWpbTa50zmSQ8t7cucYoNfxryNoaSBL6lM4T+KLXGv186b0Z/oH6Q4DEejHxGsWBVM4Jfh1QzB72NtOUoOuBY/yeWCruAFTfP41a+Qs5bMT9L2Xk0dSfu1SzvoDqu5bW2pPqAI= 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: On Thu, Jan 01, 2026 at 11:13:42PM +0100, Frederic Weisbecker wrote: > The HK_TYPE_DOMAIN housekeeping cpumask is now modifiable 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 isolated > CPU, the housekeeping subsystem 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 Acked-by: Bjorn Helgaas > --- > 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 a6111140755c..b902d8adf9a5 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 > @@ -1762,6 +1773,10 @@ 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 864775651c6f..f14f467e50de 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1206,6 +1206,7 @@ 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); > @@ -2079,6 +2080,8 @@ 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 ec3f15164fd1..5239f556745d 100644 > --- a/kernel/sched/isolation.c > +++ b/kernel/sched/isolation.c > @@ -8,6 +8,7 @@ > * > */ > #include > +#include > #include "sched.h" > > enum hk_flags { > @@ -142,6 +143,7 @@ int housekeeping_update(struct cpumask *isol_mask) > > synchronize_rcu(); > > + pci_probe_flush_workqueue(); > mem_cgroup_flush_workqueue(); > vmstat_flush_workqueue(); > > -- > 2.51.1 >