From nobody Tue Feb 10 00:22:23 2026 Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4E11B53A7 for ; Wed, 3 Apr 2024 18:30:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=46.235.227.194 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712169037; cv=none; b=DdDb5vKW8ODCjesClXb7/n5J8Mfzahc42ujXyqnoyzA8MReR5rlOdBOenDtwT90lyIDzCJLRdszyx9v3e0yqdRCbaw7w6n6efF1E1oOORGhZSGHYIcFJK/YBG7e3tQAkE44X17OjqIamGSZLJl6wvDxu539RvcIsEhU0SwMrVHI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712169037; c=relaxed/simple; bh=X3gawQizTTZ2izaFT0MnlQyxFRjnWmFQBSZh9Jvcdpw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=tuKElQ79Ot2ndciKXANUdpTIQTRwQWkFbLoCUCFe5/UY1GR9u2s6h6hq3H35kcWAQrnQPhmxT7nCtv/aY+LHAjV6PviWM2cbPxgOxhfU1lC0mcHaRi36nbNPFo4be2InXvHkk0dU3jJb21iVaYcOeqz34PNZ/17PIqboX/xnh6I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=AmTBmM3B; arc=none smtp.client-ip=46.235.227.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="AmTBmM3B" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1712169033; bh=X3gawQizTTZ2izaFT0MnlQyxFRjnWmFQBSZh9Jvcdpw=; h=From:To:Cc:Subject:Date:From; b=AmTBmM3Bjo9n+afuIZfqGHOst3XC2oURKpvaNsUIq+gCXkNBiBQrx7K2jSL6vdVeS mpTA8LNdX705fFs9Nek8/IvpOVhesw9n9sAWtO9DjCWkcRJj1YfqMVtKLzPSaNNQJQ kS5YPp/vbg+dd01t8P2RSK2w2QRTcXiHyMS/SJezDmcqenIkX14SKxnK4PM29OZDCl wrtBM8bNJeV2a7ev9wFY/Xwob2+7jQWDbWHgbmKtzeAya49/8IwZNpPX8dZDY+tMDj 2kmSQbillZk1vbXiMjh5GC2KxlCJqxwpZ9TmBm2KHKDqWedBVRjHMRab3+7ZhJzZMv QxuXGkbciCslA== Received: from localhost.localdomain (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: alarumbe) by madrid.collaboradmins.com (Postfix) with ESMTPSA id 62EFA37813D7; Wed, 3 Apr 2024 18:30:32 +0000 (UTC) From: =?UTF-8?q?Adri=C3=A1n=20Larumbe?= To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Hans de Goede Cc: kernel@collabora.com, =?UTF-8?q?Adri=C3=A1n=20Larumbe?= , Boris Brezillon , Tvrtko Ursulin , Christopher Healy , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH] drm/sysfs: Add drm class-wide attribute to get active device clients Date: Wed, 3 Apr 2024 19:29:39 +0100 Message-ID: <20240403182951.724488-1-adrian.larumbe@collabora.com> X-Mailer: git-send-email 2.44.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Up to this day, all fdinfo-based GPU profilers must traverse the entire /proc directory structure to find open DRM clients with fdinfo file descriptors. This is inefficient and time-consuming. This patch adds a new device class attribute that will install a sysfs file per DRM device, which can be queried by profilers to get a list of PIDs for their open clients. This file isn't human-readable, and it's meant to be queried only by GPU profilers like gputop and nvtop. Cc: Boris Brezillon Cc: Tvrtko Ursulin Cc: Christopher Healy Signed-off-by: Adri=C3=A1n Larumbe --- drivers/gpu/drm/drm_internal.h | 2 +- drivers/gpu/drm/drm_privacy_screen.c | 2 +- drivers/gpu/drm/drm_sysfs.c | 89 ++++++++++++++++++++++------ 3 files changed, 74 insertions(+), 19 deletions(-) diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h index 2215baef9a3e..9a399b03d11c 100644 --- a/drivers/gpu/drm/drm_internal.h +++ b/drivers/gpu/drm/drm_internal.h @@ -145,7 +145,7 @@ bool drm_master_internal_acquire(struct drm_device *dev= ); void drm_master_internal_release(struct drm_device *dev); =20 /* drm_sysfs.c */ -extern struct class *drm_class; +extern struct class drm_class; =20 int drm_sysfs_init(void); void drm_sysfs_destroy(void); diff --git a/drivers/gpu/drm/drm_privacy_screen.c b/drivers/gpu/drm/drm_pri= vacy_screen.c index 6cc39e30781f..2fbd24ba5818 100644 --- a/drivers/gpu/drm/drm_privacy_screen.c +++ b/drivers/gpu/drm/drm_privacy_screen.c @@ -401,7 +401,7 @@ struct drm_privacy_screen *drm_privacy_screen_register( mutex_init(&priv->lock); BLOCKING_INIT_NOTIFIER_HEAD(&priv->notifier_head); =20 - priv->dev.class =3D drm_class; + priv->dev.class =3D &drm_class; priv->dev.type =3D &drm_privacy_screen_type; priv->dev.parent =3D parent; priv->dev.release =3D drm_privacy_screen_device_release; diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c index a953f69a34b6..56ca9e22c720 100644 --- a/drivers/gpu/drm/drm_sysfs.c +++ b/drivers/gpu/drm/drm_sysfs.c @@ -58,8 +58,6 @@ static struct device_type drm_sysfs_device_connector =3D { .name =3D "drm_connector", }; =20 -struct class *drm_class; - #ifdef CONFIG_ACPI static bool drm_connector_acpi_bus_match(struct device *dev) { @@ -128,6 +126,62 @@ static const struct component_ops typec_connector_ops = =3D { =20 static CLASS_ATTR_STRING(version, S_IRUGO, "drm 1.1.0 20060810"); =20 +static ssize_t clients_show(struct device *cd, struct device_attribute *at= tr, char *buf) +{ + struct drm_minor *minor =3D cd->driver_data; + struct drm_device *ddev =3D minor->dev; + struct drm_file *priv; + ssize_t offset =3D 0; + void *pid_buf; + + if (minor->type !=3D DRM_MINOR_RENDER) + return 0; + + pid_buf =3D kvmalloc(PAGE_SIZE, GFP_KERNEL); + if (!pid_buf) + return 0; + + mutex_lock(&ddev->filelist_mutex); + list_for_each_entry_reverse(priv, &ddev->filelist, lhead) { + struct pid *pid; + + if (drm_WARN_ON(ddev, (PAGE_SIZE - offset) < sizeof(pid_t))) + break; + + rcu_read_lock(); + pid =3D rcu_dereference(priv->pid); + (*(pid_t *)(pid_buf + offset)) =3D pid_vnr(pid); + rcu_read_unlock(); + + offset +=3D sizeof(pid_t); + } + mutex_unlock(&ddev->filelist_mutex); + + if (offset < PAGE_SIZE) + (*(pid_t *)(pid_buf + offset)) =3D 0; + + memcpy(buf, pid_buf, offset); + + kvfree(pid_buf); + + return offset; + +} +static DEVICE_ATTR_RO(clients); + +static struct attribute *drm_device_attrs[] =3D { + &dev_attr_clients.attr, + NULL, +}; +ATTRIBUTE_GROUPS(drm_device); + +struct class drm_class =3D { + .name =3D "drm", + .dev_groups =3D drm_device_groups, +}; + +static bool drm_class_initialised; + /** * drm_sysfs_init - initialize sysfs helpers * @@ -142,18 +196,19 @@ int drm_sysfs_init(void) { int err; =20 - drm_class =3D class_create("drm"); - if (IS_ERR(drm_class)) - return PTR_ERR(drm_class); + err =3D class_register(&drm_class); + if (err) + return err; =20 - err =3D class_create_file(drm_class, &class_attr_version.attr); + err =3D class_create_file(&drm_class, &class_attr_version.attr); if (err) { - class_destroy(drm_class); - drm_class =3D NULL; + class_destroy(&drm_class); return err; } =20 - drm_class->devnode =3D drm_devnode; + drm_class.devnode =3D drm_devnode; + + drm_class_initialised =3D true; =20 drm_sysfs_acpi_register(); return 0; @@ -166,12 +221,12 @@ int drm_sysfs_init(void) */ void drm_sysfs_destroy(void) { - if (IS_ERR_OR_NULL(drm_class)) + if (!drm_class_initialised) return; drm_sysfs_acpi_unregister(); - class_remove_file(drm_class, &class_attr_version.attr); - class_destroy(drm_class); - drm_class =3D NULL; + class_remove_file(&drm_class, &class_attr_version.attr); + class_destroy(&drm_class); + drm_class_initialised =3D false; } =20 static void drm_sysfs_release(struct device *dev) @@ -372,7 +427,7 @@ int drm_sysfs_connector_add(struct drm_connector *conne= ctor) return -ENOMEM; =20 device_initialize(kdev); - kdev->class =3D drm_class; + kdev->class =3D &drm_class; kdev->type =3D &drm_sysfs_device_connector; kdev->parent =3D dev->primary->kdev; kdev->groups =3D connector_dev_groups; @@ -550,7 +605,7 @@ struct device *drm_sysfs_minor_alloc(struct drm_minor *= minor) minor_str =3D "card%d"; =20 kdev->devt =3D MKDEV(DRM_MAJOR, minor->index); - kdev->class =3D drm_class; + kdev->class =3D &drm_class; kdev->type =3D &drm_sysfs_device_minor; } =20 @@ -579,10 +634,10 @@ struct device *drm_sysfs_minor_alloc(struct drm_minor= *minor) */ int drm_class_device_register(struct device *dev) { - if (!drm_class || IS_ERR(drm_class)) + if (!drm_class_initialised) return -ENOENT; =20 - dev->class =3D drm_class; + dev->class =3D &drm_class; return device_register(dev); } EXPORT_SYMBOL_GPL(drm_class_device_register); base-commit: 45c734fdd43db14444025910b4c59dd2b8be714a --=20 2.44.0