From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 610EB32CF6D for ; Wed, 10 Sep 2025 15:42:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757518971; cv=none; b=LeQ21vjb3X02slTpUVvQeGS17FaOjRnqS/PeqRbZwYAGKEFE6qSgYxZ12YlawcRJHKW2tsaLDNookHekt8V7EG+b7zgOvm5ykUJMdywrGsDKJN/wlv+UoK5tfPcYgNCEnLf2fNl+0g6jJYOROcA7OYs5UCM5wiVlvdT/Ijxpp9c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757518971; c=relaxed/simple; bh=AjDk/9bVfSEqkQIJW5XdEY0TRjUbDLbshgB2KwEMajc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=rOixu9AOwD1xkvQORAMIROSaGC0jT04oPyhUFVOvWQWx3A2AToo9+FkDJciYl84LdK+4IcTJLS9nizi7MXXv5ZNVaAWPSroDnoKamZFZranjXHqnAIbXolLCXdjyvnFio0aItOOX79tKbRSg40IxcdLYVf7WlY7svBgfhllcOnw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7B4DF1756; Wed, 10 Sep 2025 08:42:40 -0700 (PDT) Received: from [10.1.25.55] (e122027.cambridge.arm.com [10.1.25.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 66D643F694; Wed, 10 Sep 2025 08:42:46 -0700 (PDT) Message-ID: <5a6d3ffe-1edd-4082-ad7a-85256ececa86@arm.com> Date: Wed, 10 Sep 2025 16:42:36 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/4] drm/panfrost: Display list of device JM contexts over debugfs To: =?UTF-8?Q?Adri=C3=A1n_Larumbe?= , linux-kernel@vger.kernel.org Cc: dri-devel@lists.freedesktop.org, Boris Brezillon , kernel@collabora.com, Rob Herring , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter References: <20250904001054.147465-1-adrian.larumbe@collabora.com> <20250904001054.147465-5-adrian.larumbe@collabora.com> From: Steven Price Content-Language: en-GB In-Reply-To: <20250904001054.147465-5-adrian.larumbe@collabora.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 04/09/2025 01:08, Adrián Larumbe wrote: > From: Boris Brezillon > > For DebugFS builds, create a filesystem knob that, for every single open > file of the Panfrost DRM device, shows its command name information and > PID (when applicable), and all of its existing JM contexts. > > For every context, show its priority and job config. > > Signed-off-by: Boris Brezillon > Signed-off-by: Adrián Larumbe > --- > drivers/gpu/drm/panfrost/panfrost_drv.c | 97 +++++++++++++++++++++++++ > 1 file changed, 97 insertions(+) > > diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c > index 02f704ec4961..b3d14b887da4 100644 > --- a/drivers/gpu/drm/panfrost/panfrost_drv.c > +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c > @@ -712,6 +712,48 @@ static int panthor_gems_show(struct seq_file *m, void *data) > return 0; > } > > +static void show_panfrost_jm_ctx(struct panfrost_jm_ctx *jm_ctx, u32 handle, > + struct seq_file *m) > +{ > + struct drm_device *ddev = ((struct drm_info_node *)m->private)->minor->dev; > + const char *prio = NULL; > + > + static const char * const prios[] = { > + [DRM_SCHED_PRIORITY_HIGH] = "HIGH", > + [DRM_SCHED_PRIORITY_NORMAL] = "NORMAL", > + [DRM_SCHED_PRIORITY_LOW] = "LOW", > + }; > + > + if (jm_ctx->slots[0].sched_entity.priority != > + jm_ctx->slots[1].sched_entity.priority) > + drm_warn(ddev, "Slot priorities should be the same in a single context"); > + > + if (jm_ctx->slots[0].sched_entity.priority < ARRAY_SIZE(prios)) > + prio = prios[jm_ctx->slots[0].sched_entity.priority]; > + > + seq_printf(m, " JM context %u: priority %s config %x\n", > + handle, prio ? prio : "UNKNOWN", jm_ctx->config); NIT: If you assign prio to "UNKNOWN" to begin with (rather than NULL) you can avoid this ?: operator. > +} > + > +static int show_file_jm_ctxs(struct panfrost_file_priv *pfile, > + struct seq_file *m) > +{ > + struct panfrost_jm_ctx *jm_ctx; > + unsigned long i; > + > + xa_lock(&pfile->jm_ctxs); > + xa_for_each(&pfile->jm_ctxs, i, jm_ctx) { > + jm_ctx = panfrost_jm_ctx_get(jm_ctx); > + xa_unlock(&pfile->jm_ctxs); > + show_panfrost_jm_ctx(jm_ctx, i, m); > + panfrost_jm_ctx_put(jm_ctx); > + xa_lock(&pfile->jm_ctxs); > + } > + xa_unlock(&pfile->jm_ctxs); Is it so bad if we just held the xa lock for the whole loop? It just seems unnecessarily complex. Thanks, Steve > + > + return 0; > +} > + > static struct drm_info_list panthor_debugfs_list[] = { > {"gems", panthor_gems_show, 0, NULL}, > }; > @@ -725,9 +767,64 @@ static int panthor_gems_debugfs_init(struct drm_minor *minor) > return 0; > } > > +static int show_each_file(struct seq_file *m, void *arg) > +{ > + struct drm_info_node *node = (struct drm_info_node *)m->private; > + struct drm_device *ddev = node->minor->dev; > + int (*show)(struct panfrost_file_priv *, struct seq_file *) = > + node->info_ent->data; > + struct drm_file *file; > + int ret; > + > + ret = mutex_lock_interruptible(&ddev->filelist_mutex); > + if (ret) > + return ret; > + > + list_for_each_entry(file, &ddev->filelist, lhead) { > + struct task_struct *task; > + struct panfrost_file_priv *pfile = file->driver_priv; > + struct pid *pid; > + > + /* > + * Although we have a valid reference on file->pid, that does > + * not guarantee that the task_struct who called get_pid() is > + * still alive (e.g. get_pid(current) => fork() => exit()). > + * Therefore, we need to protect this ->comm access using RCU. > + */ > + rcu_read_lock(); > + pid = rcu_dereference(file->pid); > + task = pid_task(pid, PIDTYPE_TGID); > + seq_printf(m, "client_id %8llu pid %8d command %s:\n", > + file->client_id, pid_nr(pid), > + task ? task->comm : ""); > + rcu_read_unlock(); > + > + ret = show(pfile, m); > + if (ret < 0) > + break; > + > + seq_puts(m, "\n"); > + } > + > + mutex_unlock(&ddev->filelist_mutex); > + return ret; > +} > + > +static struct drm_info_list panfrost_sched_debugfs_list[] = { > + { "sched_ctxs", show_each_file, 0, show_file_jm_ctxs }, > +}; > + > +static void panfrost_sched_debugfs_init(struct drm_minor *minor) > +{ > + drm_debugfs_create_files(panfrost_sched_debugfs_list, > + ARRAY_SIZE(panfrost_sched_debugfs_list), > + minor->debugfs_root, minor); > +} > + > static void panfrost_debugfs_init(struct drm_minor *minor) > { > panthor_gems_debugfs_init(minor); > + panfrost_sched_debugfs_init(minor); > } > #endif >