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From:   Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
To:     Intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Cc:     cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
        Tejun Heo <tj@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Zefan Li <lizefan.x@bytedance.com>,
        Dave Airlie <airlied@redhat.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Rob Clark <robdclark@chromium.org>,
        =?UTF-8?q?St=C3=A9phane=20Marchesin?= <marcheu@chromium.org>,
        "T . J . Mercier" <tjmercier@google.com>, Kenny.Ho@amd.com,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        Brian Welty <brian.welty@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Subject: [RFC 08/12] drm/cgroup: Only track clients which are providing drm_cgroup_ops
Date:   Thu, 12 Jan 2023 16:56:05 +0000
Message-Id: <20230112165609.1083270-9-tvrtko.ursulin@linux.intel.com>
In-Reply-To: <20230112165609.1083270-1-tvrtko.ursulin@linux.intel.com>
References: <20230112165609.1083270-1-tvrtko.ursulin@linux.intel.com>
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From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

To reduce the number of tracking going on, especially with drivers which
will not support any sort of control from the drm cgroup controller side,
lets express the funcionality as opt-in and use the presence of
drm_cgroup_ops as activation criteria.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/drm_cgroup.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/drm_cgroup.c b/drivers/gpu/drm/drm_cgroup.c
index ef951421bba6..09249f795af3 100644
--- a/drivers/gpu/drm/drm_cgroup.c
+++ b/drivers/gpu/drm/drm_cgroup.c
@@ -36,6 +36,9 @@ void drm_clients_close(struct drm_file *file_priv)
 
 	lockdep_assert_held(&dev->filelist_mutex);
 
+	if (!dev->driver->cg_ops)
+		return;
+
 	pid = rcu_access_pointer(file_priv->pid);
 	clients = xa_load(&drm_pid_clients, (unsigned long)pid);
 	if (drm_WARN_ON_ONCE(dev, !clients))
@@ -67,6 +70,9 @@ int drm_clients_open(struct drm_file *file_priv)
 
 	lockdep_assert_held(&dev->filelist_mutex);
 
+	if (!dev->driver->cg_ops)
+		return 0;
+
 	pid = (unsigned long)rcu_access_pointer(file_priv->pid);
 	clients = xa_load(&drm_pid_clients, pid);
 	if (!clients) {
@@ -102,6 +108,9 @@ drm_clients_migrate(struct drm_file *file_priv,
 
 	lockdep_assert_held(&dev->filelist_mutex);
 
+	if (!dev->driver->cg_ops)
+		return;
+
 	existing_clients = xa_load(&drm_pid_clients, (unsigned long)new);
 	clients = xa_load(&drm_pid_clients, (unsigned long)old);
 
-- 
2.34.1