[PATCH v2 01/11] cgroup: Introduce cgroup for drm subsystem

Kenny Ho
2020-02-26T19:01:42Z

With the increased importance of machine learning, data science and
other cloud-based applications, GPUs are already in production use in
data centers today. Existing GPU resource management is very coarse
grain, however, as sysadmins are only able to distribute workload on a
per-GPU basis. An alternative is to use GPU virtualization (with or
without SRIOV) but it generally acts on the entire GPU instead of the
specific resources in a GPU. With a drm cgroup controller, we can
enable alternate, fine-grain, sub-GPU resource management (in addition
to what may be available via GPU virtualization.)

Change-Id: Ia90aed8c4cb89ff20d8216a903a765655b44fc9a
Signed-off-by: Kenny Ho <Kenny.Ho-5C7GfCeVMHo@public.gmane.org>
---
Documentation/admin-guide/cgroup-v2.rst | 18 ++++-
Documentation/cgroup-v1/drm.rst | 1 +
include/linux/cgroup_drm.h | 92 +++++++++++++++++++++++++
include/linux/cgroup_subsys.h | 4 ++
init/Kconfig | 5 ++
kernel/cgroup/Makefile | 1 +
kernel/cgroup/drm.c | 42 +++++++++++
7 files changed, 161 insertions(+), 2 deletions(-)
create mode 100644 Documentation/cgroup-v1/drm.rst
create mode 100644 include/linux/cgroup_drm.h
create mode 100644 kernel/cgroup/drm.c

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 0636bcb60b5a..7deff912185e 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -61,8 +61,10 @@ v1 is available under Documentation/admin-guide/cgroup-v1/.
5-6. Device
5-7. RDMA
5-7-1. RDMA Interface Files
- 5-8. Misc
- 5-8-1. perf_event
+ 5-8. GPU
+ 5-8-1. GPU Interface Files
+ 5-9. Misc
+ 5-9-1. perf_event
5-N. Non-normative information
5-N-1. CPU controller root cgroup process behaviour
5-N-2. IO controller root cgroup process behaviour
@@ -2057,6 +2059,18 @@ RDMA Interface Files
ocrdma1 hca_handle=1 hca_object=23

+GPU
+---
+
+The "gpu" controller regulates the distribution and accounting of
+of GPU-related resources.
+
+GPU Interface Files
+~~~~~~~~~~~~~~~~~~~~
+
+TODO
+
+
Misc
----

diff --git a/Documentation/cgroup-v1/drm.rst b/Documentation/cgroup-v1/drm.rst
new file mode 100644
index 000000000000..5f5658e1f5ed
--- /dev/null
+++ b/Documentation/cgroup-v1/drm.rst
@@ -0,0 +1 @@
+Please see ../cgroup-v2.rst for details
diff --git a/include/linux/cgroup_drm.h b/include/linux/cgroup_drm.h
new file mode 100644
index 000000000000..345af54a5d41
--- /dev/null
+++ b/include/linux/cgroup_drm.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: MIT
+ * Copyright 2019 Advanced Micro Devices, Inc.
+ */
+#ifndef _CGROUP_DRM_H
+#define _CGROUP_DRM_H
+
+#include <linux/cgroup.h>
+
+#ifdef CONFIG_CGROUP_DRM
+
+/**
+ * The DRM cgroup controller data structure.
+ */
+struct drmcg {
+ struct cgroup_subsys_state css;
+};
+
+/**
+ * css_to_drmcg - get the corresponding drmcg ref from a cgroup_subsys_state
+ * @css: the target cgroup_subsys_state
+ *
+ * Return: DRM cgroup that contains the @css
+ */
+static inline struct drmcg *css_to_drmcg(struct cgroup_subsys_state *css)
+{
+ return css ? container_of(css, struct drmcg, css) : NULL;
+}
+
+/**
+ * drmcg_get - get the drmcg reference that a task belongs to
+ * @task: the target task
+ *
+ * This increase the reference count of the css that the @task belongs to
+ *
+ * Return: reference to the DRM cgroup the task belongs to
+ */
+static inline struct drmcg *drmcg_get(struct task_struct *task)
+{
+ return css_to_drmcg(task_get_css(task, gpu_cgrp_id));
+}
+
+/**
+ * drmcg_put - put a drmcg reference
+ * @drmcg: the target drmcg
+ *
+ * Put a reference obtained via drmcg_get
+ */
+static inline void drmcg_put(struct drmcg *drmcg)
+{
+ if (drmcg)
+ css_put(&drmcg->css);
+}
+
+/**
+ * drmcg_parent - find the parent of a drm cgroup
+ * @cg: the target drmcg
+ *
+ * This does not increase the reference count of the parent cgroup
+ *
+ * Return: parent DRM cgroup of @cg
+ */
+static inline struct drmcg *drmcg_parent(struct drmcg *cg)
+{
+ return css_to_drmcg(cg->css.parent);
+}
+
+#else /* CONFIG_CGROUP_DRM */
+
+struct drmcg {
+};
+
+static inline struct drmcg *css_to_drmcg(struct cgroup_subsys_state *css)
+{
+ return NULL;
+}
+
+static inline struct drmcg *drmcg_get(struct task_struct *task)
+{
+ return NULL;
+}
+
+static inline void drmcg_put(struct drmcg *drmcg)
+{
+}
+
+static inline struct drmcg *drmcg_parent(struct drmcg *cg)
+{
+ return NULL;
+}
+
+#endif /* CONFIG_CGROUP_DRM */
+#endif /* _CGROUP_DRM_H */
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index acb77dcff3b4..f4e627942115 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -61,6 +61,10 @@ SUBSYS(pids)
SUBSYS(rdma)
#endif

+#if IS_ENABLED(CONFIG_CGROUP_DRM)
+SUBSYS(gpu)
+#endif
+
/*
* The following subsystems are not supported on the default hierarchy.
*/
diff --git a/init/Kconfig b/init/Kconfig
index a34064a031a5..bb78dff44d9d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -965,6 +965,11 @@ config CGROUP_RDMA
Attaching processes with active RDMA resources to the cgroup
hierarchy is allowed even if can cross the hierarchy's limit.

+config CGROUP_DRM
+ bool "DRM controller (EXPERIMENTAL)"
+ help
+ Provides accounting and enforcement of resources in the DRM subsystem.
+
config CGROUP_FREEZER
bool "Freezer controller"
help
diff --git a/kernel/cgroup/Makefile b/kernel/cgroup/Makefile
index 5d7a76bfbbb7..31f186f58121 100644
--- a/kernel/cgroup/Makefile
+++ b/kernel/cgroup/Makefile
@@ -4,5 +4,6 @@ obj-y := cgroup.o rstat.o namespace.o cgroup-v1.o freezer.o
obj-$(CONFIG_CGROUP_FREEZER) += legacy_freezer.o
obj-$(CONFIG_CGROUP_PIDS) += pids.o
obj-$(CONFIG_CGROUP_RDMA) += rdma.o
+obj-$(CONFIG_CGROUP_DRM) += drm.o
obj-$(CONFIG_CPUSETS) += cpuset.o
obj-$(CONFIG_CGROUP_DEBUG) += debug.o
diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
new file mode 100644
index 000000000000..5e38a8230922
--- /dev/null
+++ b/kernel/cgroup/drm.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: MIT
+// Copyright 2019 Advanced Micro Devices, Inc.
+#include <linux/slab.h>
+#include <linux/cgroup.h>
+#include <linux/cgroup_drm.h>
+
+static struct drmcg *root_drmcg __read_mostly;
+
+static void drmcg_css_free(struct cgroup_subsys_state *css)
+{
+ struct drmcg *drmcg = css_to_drmcg(css);
+
+ kfree(drmcg);
+}
+
+static struct cgroup_subsys_state *
+drmcg_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+ struct drmcg *parent = css_to_drmcg(parent_css);
+ struct drmcg *drmcg;
+
+ drmcg = kzalloc(sizeof(struct drmcg), GFP_KERNEL);
+ if (!drmcg)
+ return ERR_PTR(-ENOMEM);
+
+ if (!parent)
+ root_drmcg = drmcg;
+
+ return &drmcg->css;
+}
+
+struct cftype files[] = {
+ { } /* terminate */
+};
+
+struct cgroup_subsys gpu_cgrp_subsys = {
+ .css_alloc = drmcg_css_alloc,
+ .css_free = drmcg_css_free,
+ .early_init = false,
+ .legacy_cftypes = files,
+ .dfl_cftypes = files,
+};
--
2.25.0