From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793822090; b=OCwSnkUDZ4iFOssXTWSOzvHLQ2I5uk8keW/gcPVF7uW1C7750pxG2zXf6hHxD1ThjSb/ 6oi+eV8cPYW75U//5yeR8KdZL3VBHnN2cM4WBrscBRK0NMd9I/qav0ETF/qQHzf/7MW+z 8zaUftvJSc9OrX4gAmD+dJgn1w3HcsXbzPvgO5/MFZaN2mAXur5qf6Z9UsMRBSXXk7jyQ 5hq9+uyOQmg4DYFLRcUVT6X6dcfMPmcO8vV+jUUb0mdnXsxno/eWwwPNnmKiFw2AFI+9P EqERpXoLsZmPMjO6zPoMlRDjWW8lGDihpvweYMliphResO/GtkuNzPjqy5/pzBsNgrQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793822090; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID: In-Reply-To:References:MIME-Version:Content-Type:X-Mailer: X-Developer-Signature:X-Developer-Key:Content-Transfer-Encoding; bh=LwOyQmkvG4TrYSsjhoNvmU1CfgZA+V6RV4LLe+r+cHk=; b=BEYbgCXGxeE8MQQ/bdPu3aJIqIAsQcIAEh3Ij4ZtkrfEcMT/4Yq3ajLTjmjdXQWl9BAV pIucu3TVLNBM253Wg45MtgS9KAB25y836JrLvhZBtu6JCwuMYSqXx8bdbmRiOzkSK4+Mx xCsfGl2OXYuW2/ci9M9MXTp1fhS58UIIHL1zhA+QuS8xEq34gXGMxAk2S+ahmNw7bL3C6 OvC5lLTMkAMm0iG47ohMS7FJ5jQXtb/lLcRUzAdZO/gcR0HjaSDjGnU/Fj5g/ekvUmH5f YcaxjjebjLniF6YdNRlHK5ahiyzJOHnQB/PvTSa6kyoOBjsFkc+8S9K69J9RsSxePsA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=mJyOhlQt; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C3F646098F56; Wed, 4 Nov 2026 19:54:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=mJyOhlQt Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D2B01F0093A; Wed, 4 Nov 2026 19:54:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793822089; bh=LwOyQmkvG4TrYSsjhoNvmU1CfgZA+V6RV4LLe+r+cHk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mJyOhlQt7v/yUeJe2KxDzjfIgCPFjEFsKvYVx2A3N/ozpWFiPJU0KUhNdF3Wnx++v sI9BCBWIdMMiP0QcpAXFpZsOn0jW7NrHt4r2cB6NkOMsL6mxo8rFKgvE84hLglCx66 OqQujMha7035TQ4ZwwiVUfu7SbYHZU96GqKi/rxAVkSUfLy231e9TMVVFOEYebJCby NOwJ0wLy1EviZyidaxTUbqL58HBSyhB/XKNBxXObC0roAJt5FLGPIUnCJuWzz6FbgG K3Yv0a5upmIEZWtQAvIYMc9ZxBopPWyj6ON1cpCflNYuRijpKAoniKAIZEUIsRrLGe wTSzOu7fuS0uw== From: Christian Brauner To: linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , Jann Horn , Josef Bacik , Chris Mason , Jeff Layton , NeilBrown , Eric Dumazet , Thomas Gleixner , Al Viro , Jonathan Corbet , Christoph Hellwig , Greg Kroah-Hartman , Joel Granados , Kees Cook , Jan Kara , Jan Kara , linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-acpi@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, linux-um@lists.infradead.org, linux-wireless@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, ntfs3@lists.linux.dev, platform-driver-x86@vger.kernel.org, coreteam@netfilter.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, netfilter-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, ibm-acpi-devel@lists.sourceforge.net, jfs-discussion@lists.sourceforge.net, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cifs@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-mm@kvack.org, linux-sh@vger.kernel.org, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, sparclinux@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-doc@vger.kernel.org, linux-serial@vger.kernel.org, linux-atm-general@lists.sourceforge.net, Takashi Iwai , linux-input@vger.kernel.org, linux-raid@vger.kernel.org, linux-ext4@vger.kernel.org, linux-modules@vger.kernel.org, linux-debuggers@vger.kernel.org, "Christian Brauner (Amutable)" , Chuck Lever Subject: [PATCH RESEND v2 20/30] sched/psi: let procfs own the wait queue of the pressure files Date: Wed, 4 Nov 2026 20:54:35 +0100 Message-ID: <20261104-work-procfs-fs-v2-20-319e0f9a8aae@kernel.org> In-Reply-To: <20261104-work-procfs-fs-v2-0-319e0f9a8aae@kernel.org> References: <20261104-work-procfs-fs-v2-0-319e0f9a8aae@kernel.org> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" X-Mailer: b4 0.17-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=6098; i=brauner@kernel.org; h=from:subject:message-id; bh=CeHhvuLOJ2DxGx1mSjted70KaKApRIjx6GoOIAUH5Kc=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWS97nEOnuN4eKv7y+UynWu9t7p/P/D2dPOuOt7MtW4RY cbN7Z4KHaUsDGJcDLJiiiwO7Sbhcst5KjYbZWrAzGFlAhnCwMUpABPZtpnhnzqLca7vmStVc8on LzvQtZvr1cV7Wl6vAr9Pan8zzeRX1XOG/zVVv26edFdZ+WTuhnfLRZpsnu+SuzP1+Nxz33L9reT Tf/MDAA== X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Content-Transfer-Encoding: 8bit A trigger on one of the /proc/pressure files has a wait queue of its own for its poller, the cgroup pressure files use the queue of their kernfs node through kernfs_generic_poll() and kernfs_notify(). procfs owns the queue of its pressure files now, so use it the same way: the poll_wait() is procfs', and a trigger that fires wakes the pollers of its file with proc_poll_notify(). Like for the cgroup files every poller of the file is woken when any trigger on it fires, and each reports the state of its own trigger. psi_trigger_poll() doesn't need the file anymore. Signed-off-by: Christian Brauner (Amutable) --- include/linux/psi.h | 3 +-- include/linux/psi_types.h | 8 +++++--- kernel/cgroup/cgroup.c | 2 +- kernel/sched/psi.c | 30 +++++++++++++++++------------- 4 files changed, 24 insertions(+), 19 deletions(-) diff --git a/include/linux/psi.h b/include/linux/psi.h index 7966e3ac03b9..c6f536631411 100644 --- a/include/linux/psi.h +++ b/include/linux/psi.h @@ -30,8 +30,7 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, int psi_trigger_create_rtpoll_worker(struct psi_group *group); void psi_trigger_destroy(struct psi_trigger *t); -__poll_t psi_trigger_poll(void **trigger_ptr, struct file *file, - poll_table *wait); +__poll_t psi_trigger_poll(void **trigger_ptr, poll_table *wait); #ifdef CONFIG_CGROUPS static inline struct psi_group *cgroup_psi(struct cgroup *cgrp) diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h index dd10c22299ab..ce772575c5da 100644 --- a/include/linux/psi_types.h +++ b/include/linux/psi_types.h @@ -8,6 +8,8 @@ #include #include +struct proc_dir_entry; + #ifdef CONFIG_PSI /* Tracked task states */ @@ -132,12 +134,12 @@ struct psi_trigger { /* Backpointer needed during trigger destruction */ struct psi_group *group; - /* Wait queue for polling */ - wait_queue_head_t event_wait; - /* Kernfs file for cgroup triggers */ struct kernfs_open_file *of; + /* /proc/pressure file for system triggers, see proc_poll_notify() */ + struct proc_dir_entry *pde; + /* Pending event flag */ int event; diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index a284225f8dc9..c5da33495ae3 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4232,7 +4232,7 @@ static __poll_t cgroup_pressure_poll(struct kernfs_open_file *of, { struct cgroup_file_ctx *ctx = of->priv; - return psi_trigger_poll(&ctx->psi.trigger, of->file, pt); + return psi_trigger_poll(&ctx->psi.trigger, pt); } static void cgroup_pressure_release(struct kernfs_open_file *of) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index cdb7a832333a..97b5e2488106 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -514,7 +514,7 @@ static void update_triggers(struct psi_group *group, u64 now, if (t->of) kernfs_notify(t->of->kn); else - wake_up_interruptible(&t->event_wait); + proc_poll_notify(t->pde); } t->last_event_time = now; /* Reset threshold breach flag once event got generated */ @@ -1327,6 +1327,9 @@ int psi_trigger_create_rtpoll_worker(struct psi_group *group) return 0; } +/* the /proc/pressure files, see psi_proc_init() */ +static struct proc_dir_entry *psi_proc_entry[NR_PSI_RESOURCES]; + struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, enum psi_res res, struct file *file, struct kernfs_open_file *of, @@ -1392,8 +1395,7 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, t->event = 0; t->last_event_time = 0; t->of = of; - if (!of) - init_waitqueue_head(&t->event_wait); + t->pde = of ? NULL : psi_proc_entry[res]; t->pending_event = false; t->aggregator = privileged ? PSI_POLL : PSI_AVGS; @@ -1441,7 +1443,7 @@ void psi_trigger_destroy(struct psi_trigger *t) if (t->of) kernfs_notify(t->of->kn); else - wake_up_interruptible(&t->event_wait); + proc_poll_notify(t->pde); if (t->aggregator == PSI_AVGS) { mutex_lock(&group->avgs_lock); @@ -1495,8 +1497,7 @@ void psi_trigger_destroy(struct psi_trigger *t) kfree(t); } -__poll_t psi_trigger_poll(void **trigger_ptr, - struct file *file, poll_table *wait) +__poll_t psi_trigger_poll(void **trigger_ptr, poll_table *wait) { __poll_t ret = DEFAULT_POLLMASK; struct psi_trigger *t; @@ -1508,10 +1509,9 @@ __poll_t psi_trigger_poll(void **trigger_ptr, if (!t) return DEFAULT_POLLMASK | EPOLLERR | EPOLLPRI; + /* a /proc/pressure file is polled on the queue procfs owns for it */ if (t->of) kernfs_generic_poll(t->of, wait); - else - poll_wait(file, &t->event_wait, wait); if (cmpxchg(&t->event, 1, 0) == 1) ret |= EPOLLPRI; @@ -1610,7 +1610,7 @@ static __poll_t psi_fop_poll(struct file *file, poll_table *wait) { struct seq_file *seq = file->private_data; - return psi_trigger_poll(&seq->private, file, wait); + return psi_trigger_poll(&seq->private, wait); } static int psi_fop_release(struct inode *inode, struct file *file) @@ -1670,11 +1670,15 @@ static int __init psi_proc_init(void) { if (psi_enable) { proc_mkdir("pressure", NULL); - proc_create("pressure/io", 0666, NULL, &psi_io_proc_ops); - proc_create("pressure/memory", 0666, NULL, &psi_memory_proc_ops); - proc_create("pressure/cpu", 0666, NULL, &psi_cpu_proc_ops); + psi_proc_entry[PSI_IO] = proc_create("pressure/io", 0666, NULL, + &psi_io_proc_ops); + psi_proc_entry[PSI_MEM] = proc_create("pressure/memory", 0666, + NULL, &psi_memory_proc_ops); + psi_proc_entry[PSI_CPU] = proc_create("pressure/cpu", 0666, NULL, + &psi_cpu_proc_ops); #ifdef CONFIG_IRQ_TIME_ACCOUNTING - proc_create("pressure/irq", 0666, NULL, &psi_irq_proc_ops); + psi_proc_entry[PSI_IRQ] = proc_create("pressure/irq", 0666, NULL, + &psi_irq_proc_ops); #endif } return 0; -- 2.53.0