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Date: Wed, 7 Feb 2024 16:28:24 +0100
From: Michal =?utf-8?Q?Koutn=C3=BD?= <mkoutny@suse.com>
To: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, 
	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?B?U3TDqXBoYW5l?= Marchesin <marcheu@chromium.org>, 
	"T . J . Mercier" <tjmercier@google.com>, Kenny.Ho@amd.com, 
	Christian =?utf-8?B?S8O2bmln?= <christian.koenig@amd.com>, Brian Welty <brian.welty@intel.com>, 
	Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Subject: Re: [RFC 1/8] cgroup: Add the DRM cgroup controller
Message-ID: <7oxj33pfscydm6vgdpl5vppxbx5htqg6rjfyd7qyg27p3bu2gk@wzl3x3dgurom>
References: <20231024160727.282960-1-tvrtko.ursulin@linux.intel.com>
 <20231024160727.282960-2-tvrtko.ursulin@linux.intel.com>
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In-Reply-To: <20231024160727.282960-2-tvrtko.ursulin@linux.intel.com>


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Hello.

On Tue, Oct 24, 2023 at 05:07:20PM +0100, Tvrtko Ursulin <tvrtko.ursulin@li=
nux.intel.com> wrote:
> +struct drm_cgroup_state {
> +	struct cgroup_subsys_state css;
> +};
> +
> +struct drm_root_cgroup_state {
> +	struct drm_cgroup_state drmcs;
> +};
> +
> +static struct drm_root_cgroup_state root_drmcs;

Special struct type for root state is uncommon.
Have=20
struct drm_cgroup_state root_drmcs;
and possible future members can be global state variables.


> +static void drmcs_free(struct cgroup_subsys_state *css)
> +{
> +	struct drm_cgroup_state *drmcs =3D css_to_drmcs(css);
> +
> +	if (drmcs !=3D &root_drmcs.drmcs)
> +		kfree(drmcs);
> +}

I think it can be relied on root cgroup not being ever free'd by cgroup
core.

Michal

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