[RFC PATCH 2/4] drm/cgroup: Add memory accounting to DRM cgroup

Maarten Lankhorst
2023-05-03T09:00:27Z

Based roughly on the rdma and misc cgroup controllers, with a lot of
the accounting code borrowed from rdma.

The interface is simple:
- populate drmcgroup_device->regions[..] name and size for each active
region.
- Call drm(m)cg_register_device()
- Use drmcg_try_charge to check if you can allocate a chunk of memory,
use drmcg_uncharge when freeing it. This may return an error code,
or -EAGAIN when the cgroup limit is reached.

The ttm code transforms -EAGAIN back to -ENOSPC since it has specific
logic for -ENOSPC, and returning -EAGAIN to userspace causes drmIoctl
to restart infinitely.

This API allows you to limit stuff with cgroups.
You can see the supported cards in /sys/fs/cgroup/drm.capacity
You need to echo +drm to cgroup.subtree_control, and then you can
partition memory.

In each cgroup subdir:
drm.max shows the current limits of the cgroup.
drm.current the current amount of allocated memory used by this cgroup.
drm.events shows the amount of time max memory was reached.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
Documentation/admin-guide/cgroup-v2.rst | 46 ++
Documentation/gpu/drm-compute.rst | 54 +++
include/linux/cgroup_drm.h | 81 ++++
kernel/cgroup/drm.c | 539 +++++++++++++++++++++++-
4 files changed, 699 insertions(+), 21 deletions(-)
create mode 100644 Documentation/gpu/drm-compute.rst

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index f67c0829350b..b858d99cb2ef 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -2374,6 +2374,52 @@ RDMA Interface Files
mlx4_0 hca_handle=1 hca_object=20
ocrdma1 hca_handle=1 hca_object=23

+DRM
+----
+
+The "drm" controller regulates the distribution and accounting of
+DRM resources.
+
+DRM Interface Files
+~~~~~~~~~~~~~~~~~~~~
+
+ drm.max
+ A readwrite nested-keyed file that exists for all the cgroups
+ except root that describes current configured resource limit
+ for a DRM device.
+
+ Lines are keyed by device name and are not ordered.
+ Each line contains space separated resource name and its configured
+ limit that can be distributed.
+
+ The following nested keys are defined.
+
+ ========== =======================================================
+ region.* Maximum amount of bytes that allocatable in this region
+ ========== =======================================================
+
+ An example for xe follows::
+
+ 0000:03:00.0 region.vram0=1073741824 region.stolen=max
+
+ drm.capacity
+ A read-only file that describes maximum region capacity.
+ It only exists on the root cgroup. Not all memory can be
+ allocated by cgroups, as the kernel reserves some for
+ internal use.
+
+ An example for xe follows::
+
+ 0000:03:00.0 region.vram0=8514437120 region.stolen=67108864
+
+ drm.current
+ A read-only file that describes current resource usage.
+ It exists for all the cgroup except root.
+
+ An example for xe follows::
+
+ 0000:03:00.0 region.vram0=12550144 region.stolen=8650752
+
HugeTLB
-------

diff --git a/Documentation/gpu/drm-compute.rst b/Documentation/gpu/drm-compute.rst
new file mode 100644
index 000000000000..116270976ef7
--- /dev/null
+++ b/Documentation/gpu/drm-compute.rst
@@ -0,0 +1,54 @@
+==================================
+Long running workloads and compute
+==================================
+
+Long running workloads (compute) are workloads that will not complete in 10
+seconds. (The time let the user wait before he reaches for the power button).
+This means that other techniques need to be used to manage those workloads,
+that cannot use fences.
+
+Some hardware may schedule compute jobs, and have no way to pre-empt them, or
+have their memory swapped out from them. Or they simply want their workload
+not to be preempted or swapped out at all.
+
+This means that it differs from what is described in driver-api/dma-buf.rst.
+
+As with normal compute jobs, dma-fence may not be used at all. In this case,
+not even to force preemption. The driver with is simply forced to unmap a BO
+from the long compute job's address space on unbind immediately, not even
+waiting for the workload to complete. Effectively this terminates the workload
+when there is no hardware support to recover.
+
+Since this is undesirable, there need to be mitigations to prevent a workload
+from being terminated. There are several possible approach, all with their
+advantages and drawbacks.
+
+The first approach you will likely try is to pin all buffers used by compute.
+This guarantees that the job will run uninterrupted, but also allows a very
+denial of service attack by pinning as much memory as possible, hogging the
+all GPU memory, and possibly a huge chunk of CPU memory.
+
+A second approach that will work slightly better on its own is adding an option
+not to evict when creating a new job (any kind). If all of userspace opts in
+to this flag, it would prevent cooperating userspace from forced terminating
+older compute jobs to start a new one.
+
+If job preemption and recoverable pagefaults are not available, those are the
+only approaches possible. So even with those, you want a separate way of
+controlling resources. The standard kernel way of doing so is cgroups.
+
+This creates a third option, using cgroups to prevent eviction. Both GPU and
+driver-allocated CPU memory would be accounted to the correct cgroup, and
+eviction would be made cgroup aware. This allows the GPU to be partitioned
+into cgroups, that will allow jobs to run next to each other without
+interference.
+
+The interface to the cgroup would be similar to the current CPU memory
+interface, with similar semantics for min/low/high/max, if eviction can
+be made cgroup aware. For now only max is implemented.
+
+What should be noted is that each memory region (tiled memory for example)
+should have its own accounting, using $card key0 = value0 key1 = value1.
+
+The key is set to the regionid set by the driver, for example "tile0".
+For the value of $card, we use drmGetUnique().
diff --git a/include/linux/cgroup_drm.h b/include/linux/cgroup_drm.h
index 8ef66a47619f..4f17b1c85f47 100644
--- a/include/linux/cgroup_drm.h
+++ b/include/linux/cgroup_drm.h
@@ -6,4 +6,85 @@
#ifndef _CGROUP_DRM_H
#define _CGROUP_DRM_H

+#include <linux/types.h>
+
+#include <drm/drm_managed.h>
+
+struct drm_device;
+struct drm_file;
+
+struct drmcgroup_state;
+
+/*
+ * Use 8 as max, because of N^2 lookup when setting things, can be bumped if needed
+ * Identical to TTM_NUM_MEM_TYPES to allow simplifying that code.
+ */
+#define DRMCG_MAX_REGIONS 8
+
+struct drmcgroup_device {
+ struct list_head list;
+ struct list_head pools;
+
+ struct {
+ u64 size;
+ const char *name;
+ } regions[DRMCG_MAX_REGIONS];
+
+ /* Name describing the card, set by drmcg_register_device */
+ const char *name;
+
+};
+
+#if IS_ENABLED(CONFIG_CGROUP_DRM)
+int drmcg_register_device(struct drm_device *dev,
+ struct drmcgroup_device *drm_cg);
+void drmcg_unregister_device(struct drmcgroup_device *cgdev);
+int drmcg_try_charge(struct drmcgroup_state **drmcg,
+ struct drmcgroup_device *cgdev,
+ u32 index, u64 size);
+void drmcg_uncharge(struct drmcgroup_state *drmcg,
+ struct drmcgroup_device *cgdev,
+ u32 index, u64 size);
+#else
+static inline int
+drmcg_register_device(struct drm_device *dev,
+ struct drm_cgroup *drm_cg)
+{
+ return 0;
+}
+
+static inline void drmcg_unregister_device(struct drmcgroup_device *cgdev)
+{
+}
+
+static inline int drmcg_try_charge(struct drmcgroup_state **drmcg,
+ struct drmcgroup_device *cgdev,
+ u32 index, u64 size)
+{
+ *drmcg = NULL;
+ return 0;
+}
+
+static inline void drmcg_uncharge(struct drmcgroup_state *drmcg,
+ struct drmcgroup_device *cgdev,
+ u32 index, u64 size)
+{ }
+#endif
+
+static inline void drmmcg_unregister_device(struct drm_device *dev, void *arg)
+{
+ drmcg_unregister_device(arg);
+}
+
+/*
+ * This needs to be done as inline, because cgroup lives in the core
+ * kernel and it cannot call drm calls directly
+ */
+static inline int drmmcg_register_device(struct drm_device *dev,
+ struct drmcgroup_device *cgdev)
+{
+ return drmcg_register_device(dev, cgdev) ?:
+ drmm_add_action_or_reset(dev, drmmcg_unregister_device, cgdev);
+}
+
#endif /* _CGROUP_DRM_H */
diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
index 02c8eaa633d3..a93d9344fd36 100644
--- a/kernel/cgroup/drm.c
+++ b/kernel/cgroup/drm.c
@@ -1,60 +1,557 @@
-/* SPDX-License-Identifier: MIT */
+// SPDX-License-Identifier: GPL-2.0
/*
- * Copyright © 2023 Intel Corporation
+ * Copyright 2023 Intel
+ * Partially based on the rdma and misc controllers, which bear the following copyrights:
+ *
+ * Copyright 2020 Google LLC
+ * Copyright (C) 2016 Parav Pandit <pandit.parav@gmail.com>
*/

#include <linux/cgroup.h>
#include <linux/cgroup_drm.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/parser.h>
#include <linux/slab.h>

-struct drm_cgroup_state {
+#include <drm/drm_device.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_file.h>
+#include <drm/drm_managed.h>
+
+struct drmcgroup_state {
struct cgroup_subsys_state css;
+
+ struct list_head pools;
};

-struct drm_root_cgroup_state {
- struct drm_cgroup_state drmcs;
+struct drmcgroup_pool_state {
+ struct drmcgroup_device *device;
+ struct drmcgroup_resource {
+ s64 max, used;
+ } resources[DRMCG_MAX_REGIONS];
+
+ s64 usage_sum;
+
+ struct list_head cg_node;
+ struct list_head dev_node;
};

-static struct drm_root_cgroup_state root_drmcs;
+static DEFINE_MUTEX(drmcg_mutex);
+static LIST_HEAD(drmcg_devices);

-static inline struct drm_cgroup_state *
+static inline struct drmcgroup_state *
css_to_drmcs(struct cgroup_subsys_state *css)
{
- return container_of(css, struct drm_cgroup_state, css);
+ return container_of(css, struct drmcgroup_state, css);
+}
+
+static inline struct drmcgroup_state *get_current_drmcg(void)
+{
+ return css_to_drmcs(task_get_css(current, drm_cgrp_id));
+}
+
+static struct drmcgroup_state *parent_drmcg(struct drmcgroup_state *cg)
+{
+ return css_to_drmcs(cg->css.parent);
+}
+
+static void free_cg_pool_locked(struct drmcgroup_pool_state *pool)
+{
+ lockdep_assert_held(&drmcg_mutex);
+
+ list_del(&pool->cg_node);
+ list_del(&pool->dev_node);
+ kfree(pool);
+}
+
+static void
+set_resource_max(struct drmcgroup_pool_state *pool, int i, u64 new_max)
+{
+ pool->resources[i].max = new_max;
+}
+
+static void set_all_resource_max_limit(struct drmcgroup_pool_state *rpool)
+{
+ int i;
+
+ for (i = 0; i < DRMCG_MAX_REGIONS; i++)
+ set_resource_max(rpool, i, S64_MAX);
+}
+
+static void drmcs_offline(struct cgroup_subsys_state *css)
+{
+ struct drmcgroup_state *drmcs = css_to_drmcs(css);
+ struct drmcgroup_pool_state *pool, *next;
+
+ mutex_lock(&drmcg_mutex);
+ list_for_each_entry_safe(pool, next, &drmcs->pools, cg_node) {
+ if (!pool->usage_sum) {
+ free_cg_pool_locked(pool);
+ } else {
+ /* Reset all regions, last uncharge will remove pool */
+ set_all_resource_max_limit(pool);
+ }
+ }
+ mutex_unlock(&drmcg_mutex);
}

static void drmcs_free(struct cgroup_subsys_state *css)
{
- struct drm_cgroup_state *drmcs = css_to_drmcs(css);
+ struct drmcgroup_state *drmcs = css_to_drmcs(css);

- if (drmcs != &root_drmcs.drmcs)
- kfree(drmcs);
+ kfree(drmcs);
}

static struct cgroup_subsys_state *
drmcs_alloc(struct cgroup_subsys_state *parent_css)
{
- struct drm_cgroup_state *drmcs;
+ struct drmcgroup_state *drmcs = kzalloc(sizeof(*drmcs), GFP_KERNEL);
+ if (!drmcs)
+ return ERR_PTR(-ENOMEM);
+
+ INIT_LIST_HEAD(&drmcs->pools);
+ return &drmcs->css;
+}
+
+static struct drmcgroup_pool_state *
+find_cg_pool_locked(struct drmcgroup_state *drmcs, struct drmcgroup_device *dev)
+{
+ struct drmcgroup_pool_state *pool;
+
+ list_for_each_entry(pool, &drmcs->pools, cg_node)
+ if (pool->device == dev)
+ return pool;
+
+ return NULL;
+}
+
+static struct drmcgroup_pool_state *
+get_cg_pool_locked(struct drmcgroup_state *drmcs, struct drmcgroup_device *dev)
+{
+ struct drmcgroup_pool_state *pool;
+
+ pool = find_cg_pool_locked(drmcs, dev);
+ if (pool)
+ return pool;
+
+ pool = kzalloc(sizeof(*pool), GFP_KERNEL);
+ if (!pool)
+ return ERR_PTR(-ENOMEM);
+
+ pool->device = dev;
+ set_all_resource_max_limit(pool);

- if (!parent_css) {
- drmcs = &root_drmcs.drmcs;
- } else {
- drmcs = kzalloc(sizeof(*drmcs), GFP_KERNEL);
- if (!drmcs)
- return ERR_PTR(-ENOMEM);
+ INIT_LIST_HEAD(&pool->cg_node);
+ INIT_LIST_HEAD(&pool->dev_node);
+ list_add_tail(&pool->cg_node, &drmcs->pools);
+ list_add_tail(&pool->dev_node, &dev->pools);
+ return pool;
+}
+
+void drmcg_unregister_device(struct drmcgroup_device *cgdev)
+{
+ struct drmcgroup_pool_state *pool, *next;
+
+ mutex_lock(&drmcg_mutex);
+ list_del(&cgdev->list);
+
+ list_for_each_entry_safe(pool, next, &cgdev->pools, dev_node)
+ free_cg_pool_locked(pool);
+ mutex_unlock(&drmcg_mutex);
+ kfree(cgdev->name);
+}
+
+EXPORT_SYMBOL_GPL(drmcg_unregister_device);
+
+int drmcg_register_device(struct drm_device *dev,
+ struct drmcgroup_device *cgdev)
+{
+ char *name = kstrdup(dev->unique, GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&cgdev->pools);
+ mutex_lock(&drmcg_mutex);
+ cgdev->name = name;
+ list_add_tail(&cgdev->list, &drmcg_devices);
+ mutex_unlock(&drmcg_mutex);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(drmcg_register_device);
+
+static int drmcg_max_show(struct seq_file *sf, void *v)
+{
+ struct drmcgroup_state *drmcs = css_to_drmcs(seq_css(sf));
+ struct drmcgroup_pool_state *pool;
+
+ mutex_lock(&drmcg_mutex);
+ list_for_each_entry(pool, &drmcs->pools, cg_node) {
+ struct drmcgroup_device *dev = pool->device;
+ int i;
+
+ seq_puts(sf, dev->name);
+
+ for (i = 0; i < DRMCG_MAX_REGIONS; i++) {
+ if (!dev->regions[i].name)
+ continue;
+
+ if (pool->resources[i].max < S64_MAX)
+ seq_printf(sf, " region.%s=%lld", dev->regions[i].name,
+ pool->resources[i].max);
+ else
+ seq_printf(sf, " region.%s=max", dev->regions[i].name);
+ }
+
+ seq_putc(sf, '\n');
}
+ mutex_unlock(&drmcg_mutex);

- return &drmcs->css;
+ return 0;
+}
+
+static struct drmcgroup_device *drmcg_get_device_locked(const char *name)
+{
+ struct drmcgroup_device *dev;
+
+ lockdep_assert_held(&drmcg_mutex);
+
+ list_for_each_entry(dev, &drmcg_devices, list)
+ if (!strcmp(name, dev->name))
+ return dev;
+
+ return NULL;
+}
+
+static void try_to_free_cg_pool_locked(struct drmcgroup_pool_state *pool)
+{
+ struct drmcgroup_device *dev = pool->device;
+ u32 i;
+
+ /* Memory charged to this pool */
+ if (pool->usage_sum)
+ return;
+
+ for (i = 0; i < DRMCG_MAX_REGIONS; i++) {
+ if (!dev->regions[i].name)
+ continue;
+
+ /* Is a specific limit set? */
+ if (pool->resources[i].max < S64_MAX)
+ return;
+ }
+
+ /*
+ * No user of the pool and all entries are set to defaults;
+ * safe to delete this pool.
+ */
+ free_cg_pool_locked(pool);
+}
+
+
+static void
+uncharge_cg_locked(struct drmcgroup_state *drmcs,
+ struct drmcgroup_device *cgdev,
+ u32 index, u64 size)
+{
+ struct drmcgroup_pool_state *pool;
+
+ pool = find_cg_pool_locked(drmcs, cgdev);
+
+ if (unlikely(!pool)) {
+ pr_warn("Invalid device %p or drm cgroup %p\n", cgdev, drmcs);
+ return;
+ }
+
+ pool->resources[index].used -= size;
+
+ /*
+ * A negative count (or overflow) is invalid,
+ * it indicates a bug in the rdma controller.
+ */
+ WARN_ON_ONCE(pool->resources[index].used < 0);
+ pool->usage_sum--;
+ try_to_free_cg_pool_locked(pool);
+}
+
+static void drmcg_uncharge_hierarchy(struct drmcgroup_state *drmcs,
+ struct drmcgroup_device *cgdev,
+ struct drmcgroup_state *stop_cg,
+ u32 index, u64 size)
+{
+ struct drmcgroup_state *p;
+
+ mutex_lock(&drmcg_mutex);
+
+ for (p = drmcs; p != stop_cg; p = parent_drmcg(p))
+ uncharge_cg_locked(p, cgdev, index, size);
+
+ mutex_unlock(&drmcg_mutex);
+
+ css_put(&drmcs->css);
+}
+
+void drmcg_uncharge(struct drmcgroup_state *drmcs,
+ struct drmcgroup_device *cgdev,
+ u32 index,
+ u64 size)
+{
+ if (index >= DRMCG_MAX_REGIONS)
+ return;
+
+ drmcg_uncharge_hierarchy(drmcs, cgdev, NULL, index, size);
+}
+EXPORT_SYMBOL_GPL(drmcg_uncharge);
+
+int drmcg_try_charge(struct drmcgroup_state **drmcs,
+ struct drmcgroup_device *cgdev,
+ u32 index,
+ u64 size)
+{
+ struct drmcgroup_state *cg, *p;
+ struct drmcgroup_pool_state *pool;
+ u64 new;
+ int ret = 0;
+
+ if (index >= DRMCG_MAX_REGIONS)
+ return -EINVAL;
+
+ /*
+ * hold on to css, as cgroup can be removed but resource
+ * accounting happens on css.
+ */
+ cg = get_current_drmcg();
+
+ mutex_lock(&drmcg_mutex);
+ for (p = cg; p; p = parent_drmcg(p)) {
+ pool = get_cg_pool_locked(p, cgdev);
+ if (IS_ERR(pool)) {
+ ret = PTR_ERR(pool);
+ goto err;
+ } else {
+ new = pool->resources[index].used + size;
+ if (new > pool->resources[index].max || new > S64_MAX) {
+ ret = -EAGAIN;
+ goto err;
+ } else {
+ pool->resources[index].used = new;
+ pool->usage_sum++;
+ }
+ }
+ }
+ mutex_unlock(&drmcg_mutex);
+
+ *drmcs = cg;
+ return 0;
+
+err:
+ mutex_unlock(&drmcg_mutex);
+ drmcg_uncharge_hierarchy(cg, cgdev, p, index, size);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(drmcg_try_charge);
+
+static s64 parse_resource(char *c, char **retname)
+{
+ substring_t argstr;
+ char *name, *value = c;
+ size_t len;
+ int ret;
+ u64 retval;
+
+ name = strsep(&value, "=");
+ if (!name || !value)
+ return -EINVAL;
+
+ /* Only support region setting for now */
+ if (strncmp(name, "region.", 7))
+ return -EINVAL;
+ else
+ name += 7;
+
+ *retname = name;
+ len = strlen(value);
+
+ argstr.from = value;
+ argstr.to = value + len;
+
+ ret = match_u64(&argstr, &retval);
+ if (ret >= 0) {
+ if (retval > S64_MAX)
+ return -EINVAL;
+ return retval;
+ }
+ if (!strncmp(value, "max", len))
+ return S64_MAX;
+
+ /* Not u64 or max, error */
+ return -EINVAL;
+}
+
+static int drmcg_parse_limits(char *options,
+ u64 *limits, char **enables)
+{
+ char *c;
+ int num_limits = 0;
+
+ /* parse resource options */
+ while ((c = strsep(&options, " ")) != NULL) {
+ s64 limit;
+
+ if (num_limits >= DRMCG_MAX_REGIONS)
+ return -EINVAL;
+
+ limit = parse_resource(c, &enables[num_limits]);
+ if (limit < 0)
+ return limit;
+
+ limits[num_limits++] = limit;
+ }
+ return num_limits;
+}
+
+static ssize_t drmcg_max_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct drmcgroup_state *drmcs = css_to_drmcs(of_css(of));
+ struct drmcgroup_device *dev;
+ struct drmcgroup_pool_state *pool;
+ char *options = strstrip(buf);
+ char *dev_name = strsep(&options, " ");
+ u64 limits[DRMCG_MAX_REGIONS];
+ u64 new_limits[DRMCG_MAX_REGIONS];
+ char *regions[DRMCG_MAX_REGIONS];
+ int num_limits, i;
+ unsigned long set_mask = 0;
+ int err = 0;
+
+ if (!dev_name)
+ return -EINVAL;
+
+ num_limits = drmcg_parse_limits(options, limits, regions);
+ if (num_limits < 0)
+ return num_limits;
+ if (!num_limits)
+ return -EINVAL;
+
+ /*
+ * Everything is parsed into key=value pairs now, take lock and attempt to update
+ * For good measure, set -EINVAL when a key is set twice.
+ */
+ mutex_lock(&drmcg_mutex);
+
+ dev = drmcg_get_device_locked(dev_name);
+ if (!dev) {
+ err = -ENODEV;
+ goto err;
+ }
+
+ pool = get_cg_pool_locked(drmcs, dev);
+ if (IS_ERR(pool)) {
+ err = PTR_ERR(pool);
+ goto err;
+ }
+
+ /* Lookup region names and set new_limits to the index */
+ for (i = 0; i < num_limits; i++) {
+ int j;
+
+ for (j = 0; j < DRMCG_MAX_REGIONS; j++)
+ if (dev->regions[j].name &&
+ !strcmp(regions[i], dev->regions[j].name))
+ break;
+
+ if (j == DRMCG_MAX_REGIONS ||
+ set_mask & BIT(j)) {
+ err = -EINVAL;
+ goto err_put;
+ }
+
+ set_mask |= BIT(j);
+ new_limits[j] = limits[i];
+ }
+
+ /* And commit */
+ for_each_set_bit(i, &set_mask, DRMCG_MAX_REGIONS)
+ set_resource_max(pool, i, new_limits[i]);
+
+err_put:
+ try_to_free_cg_pool_locked(pool);
+err:
+ mutex_unlock(&drmcg_mutex);
+
+ return err ?: nbytes;
+}
+
+static int drmcg_current_show(struct seq_file *sf, void *v)
+{
+ struct drmcgroup_state *drmcs = css_to_drmcs(seq_css(sf));
+ struct drmcgroup_device *dev;
+
+ mutex_lock(&drmcg_mutex);
+ list_for_each_entry(dev, &drmcg_devices, list) {
+ struct drmcgroup_pool_state *pool = find_cg_pool_locked(drmcs, dev);
+ int i;
+
+ seq_puts(sf, dev->name);
+
+ for (i = 0; i < DRMCG_MAX_REGIONS; i++) {
+ if (!dev->regions[i].name)
+ continue;
+
+ seq_printf(sf, " region.%s=%lld", dev->regions[i].name,
+ pool ? pool->resources[i].used : 0ULL);
+ }
+
+ seq_putc(sf, '\n');
+ }
+ mutex_unlock(&drmcg_mutex);
+
+ return 0;
+}
+
+static int drmcg_capacity_show(struct seq_file *sf, void *v)
+{
+ struct drmcgroup_device *dev;
+ int i;
+
+ list_for_each_entry(dev, &drmcg_devices, list) {
+ seq_puts(sf, dev->name);
+ for (i = 0; i < DRMCG_MAX_REGIONS; i++)
+ if (dev->regions[i].name)
+ seq_printf(sf, " region.%s=%lld",
+ dev->regions[i].name,
+ dev->regions[i].size);
+ seq_putc(sf, '\n');
+ }
+ return 0;
}

-struct cftype files[] = {
+static struct cftype files[] = {
+ {
+ .name = "max",
+ .write = drmcg_max_write,
+ .seq_show = drmcg_max_show,
+ .flags = CFTYPE_NOT_ON_ROOT,
+ },
+ {
+ .name = "current",
+ .seq_show = drmcg_current_show,
+ .flags = CFTYPE_NOT_ON_ROOT,
+ },
+ {
+ .name = "capacity",
+ .seq_show = drmcg_capacity_show,
+ .flags = CFTYPE_ONLY_ON_ROOT,
+ },
{ } /* Zero entry terminates. */
};

struct cgroup_subsys drm_cgrp_subsys = {
.css_alloc = drmcs_alloc,
.css_free = drmcs_free,
- .early_init = false,
+ .css_offline = drmcs_offline,
.legacy_cftypes = files,
.dfl_cftypes = files,
};
--
2.34.1