The cgroup controller provides accounting for GPU and GPU-related
memory allocations. The memory being accounted can be device memory or
memory allocated from pools dedicated to serve GPU-related tasks.
This patch adds APIs to:
-allow a device to register for memory accounting using the GPU cgroup
controller.
-charge and uncharge allocated memory to a cgroup.
When the cgroup controller is enabled, it would expose information about
the memory allocated by each device(registered for GPU cgroup memory
accounting) for each cgroup.
The API/UAPI can be extended to set per-device/total allocation limits
in the future.
The cgroup controller has been named following the discussion in [1].
[1]: https://lore.kernel.org/amd-gfx/YCJp%2F%[email protected]/
From: Hridya Valsaraju <[email protected]>
Signed-off-by: Hridya Valsaraju <[email protected]>
Co-developed-by: T.J. Mercier <[email protected]>
Signed-off-by: T.J. Mercier <[email protected]>
---
changes in v2
- Fix incorrect Kconfig help section indentation per Randy Dunlap.
include/linux/cgroup_gpu.h | 127 ++++++++++++++
include/linux/cgroup_subsys.h | 4 +
init/Kconfig | 7 +
kernel/cgroup/Makefile | 1 +
kernel/cgroup/gpu.c | 304 ++++++++++++++++++++++++++++++++++
5 files changed, 443 insertions(+)
create mode 100644 include/linux/cgroup_gpu.h
create mode 100644 kernel/cgroup/gpu.c
diff --git a/include/linux/cgroup_gpu.h b/include/linux/cgroup_gpu.h
new file mode 100644
index 000000000000..c5bc2b882783
--- /dev/null
+++ b/include/linux/cgroup_gpu.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: MIT
+ * Copyright 2019 Advanced Micro Devices, Inc.
+ * Copyright (C) 2022 Google LLC.
+ */
+#ifndef _CGROUP_GPU_H
+#define _CGROUP_GPU_H
+
+#include <linux/cgroup.h>
+#include <linux/page_counter.h>
+
+#ifdef CONFIG_CGROUP_GPU
+ /* The GPU cgroup controller data structure */
+struct gpucg {
+ struct cgroup_subsys_state css;
+
+ /* list of all resource pools that belong to this cgroup */
+ struct list_head rpools;
+};
+
+struct gpucg_device {
+ /*
+ * list of various resource pools in various cgroups that the device is
+ * part of.
+ */
+ struct list_head rpools;
+
+ /* list of all devices registered for GPU cgroup accounting */
+ struct list_head dev_node;
+
+ /*
+ * pointer to string literal to be used as identifier for accounting and
+ * limit setting
+ */
+ const char *name;
+};
+
+/**
+ * css_to_gpucg - get the corresponding gpucg ref from a cgroup_subsys_state
+ * @css: the target cgroup_subsys_state
+ *
+ * Returns: gpu cgroup that contains the @css
+ */
+static inline struct gpucg *css_to_gpucg(struct cgroup_subsys_state *css)
+{
+ return css ? container_of(css, struct gpucg, css) : NULL;
+}
+
+/**
+ * gpucg_get - get the gpucg reference that a task belongs to
+ * @task: the target task
+ *
+ * This increases the reference count of the css that the @task belongs to.
+ *
+ * Returns: reference to the gpu cgroup the task belongs to.
+ */
+static inline struct gpucg *gpucg_get(struct task_struct *task)
+{
+ if (!cgroup_subsys_enabled(gpu_cgrp_subsys))
+ return NULL;
+ return css_to_gpucg(task_get_css(task, gpu_cgrp_id));
+}
+
+/**
+ * gpucg_put - put a gpucg reference
+ * @gpucg: the target gpucg
+ *
+ * Put a reference obtained via gpucg_get
+ */
+static inline void gpucg_put(struct gpucg *gpucg)
+{
+ if (gpucg)
+ css_put(&gpucg->css);
+}
+
+/**
+ * gpucg_parent - find the parent of a gpu cgroup
+ * @cg: the target gpucg
+ *
+ * This does not increase the reference count of the parent cgroup
+ *
+ * Returns: parent gpu cgroup of @cg
+ */
+static inline struct gpucg *gpucg_parent(struct gpucg *cg)
+{
+ return css_to_gpucg(cg->css.parent);
+}
+
+int gpucg_try_charge(struct gpucg *gpucg, struct gpucg_device *device, u64 usage);
+void gpucg_uncharge(struct gpucg *gpucg, struct gpucg_device *device, u64 usage);
+void gpucg_register_device(struct gpucg_device *gpucg_dev, const char *name);
+#else /* CONFIG_CGROUP_GPU */
+
+struct gpucg;
+struct gpucg_device;
+
+static inline struct gpucg *css_to_gpucg(struct cgroup_subsys_state *css)
+{
+ return NULL;
+}
+
+static inline struct gpucg *gpucg_get(struct task_struct *task)
+{
+ return NULL;
+}
+
+static inline void gpucg_put(struct gpucg *gpucg) {}
+
+static inline struct gpucg *gpucg_parent(struct gpucg *cg)
+{
+ return NULL;
+}
+
+static inline int gpucg_try_charge(struct gpucg *gpucg,
+ struct gpucg_device *device,
+ u64 usage)
+{
+ return 0;
+}
+
+static inline void gpucg_uncharge(struct gpucg *gpucg,
+ struct gpucg_device *device,
+ u64 usage) {}
+
+static inline void gpucg_register_device(struct gpucg_device *gpucg_dev,
+ const char *name) {}
+#endif /* CONFIG_CGROUP_GPU */
+#endif /* _CGROUP_GPU_H */
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index 445235487230..46a2a7b93c41 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -65,6 +65,10 @@ SUBSYS(rdma)
SUBSYS(misc)
#endif
+#if IS_ENABLED(CONFIG_CGROUP_GPU)
+SUBSYS(gpu)
+#endif
+
/*
* The following subsystems are not supported on the default hierarchy.
*/
diff --git a/init/Kconfig b/init/Kconfig
index e9119bf54b1f..43568472930a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -980,6 +980,13 @@ config BLK_CGROUP
See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
+config CGROUP_GPU
+ bool "gpu cgroup controller (EXPERIMENTAL)"
+ select PAGE_COUNTER
+ help
+ Provides accounting and limit setting for memory allocations by the GPU and
+ GPU-related subsystems.
+
config CGROUP_WRITEBACK
bool
depends on MEMCG && BLK_CGROUP
diff --git a/kernel/cgroup/Makefile b/kernel/cgroup/Makefile
index 12f8457ad1f9..be95a5a532fc 100644
--- a/kernel/cgroup/Makefile
+++ b/kernel/cgroup/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_CGROUP_RDMA) += rdma.o
obj-$(CONFIG_CPUSETS) += cpuset.o
obj-$(CONFIG_CGROUP_MISC) += misc.o
obj-$(CONFIG_CGROUP_DEBUG) += debug.o
+obj-$(CONFIG_CGROUP_GPU) += gpu.o
diff --git a/kernel/cgroup/gpu.c b/kernel/cgroup/gpu.c
new file mode 100644
index 000000000000..3e9bfb45c6af
--- /dev/null
+++ b/kernel/cgroup/gpu.c
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: MIT
+// Copyright 2019 Advanced Micro Devices, Inc.
+// Copyright (C) 2022 Google LLC.
+
+#include <linux/cgroup.h>
+#include <linux/cgroup_gpu.h>
+#include <linux/mm.h>
+#include <linux/page_counter.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+
+static struct gpucg *root_gpucg __read_mostly;
+
+/*
+ * Protects list of resource pools maintained on per cgroup basis
+ * and list of devices registered for memory accounting using the GPU cgroup
+ * controller.
+ */
+static DEFINE_MUTEX(gpucg_mutex);
+static LIST_HEAD(gpucg_devices);
+
+struct gpucg_resource_pool {
+ /* The device whose resource usage is tracked by this resource pool */
+ struct gpucg_device *device;
+
+ /* list of all resource pools for the cgroup */
+ struct list_head cg_node;
+
+ /*
+ * list maintained by the gpucg_device to keep track of its
+ * resource pools
+ */
+ struct list_head dev_node;
+
+ /* tracks memory usage of the resource pool */
+ struct page_counter total;
+};
+
+static void free_cg_rpool_locked(struct gpucg_resource_pool *rpool)
+{
+ lockdep_assert_held(&gpucg_mutex);
+
+ list_del(&rpool->cg_node);
+ list_del(&rpool->dev_node);
+ kfree(rpool);
+}
+
+static void gpucg_css_free(struct cgroup_subsys_state *css)
+{
+ struct gpucg_resource_pool *rpool, *tmp;
+ struct gpucg *gpucg = css_to_gpucg(css);
+
+ // delete all resource pools
+ mutex_lock(&gpucg_mutex);
+ list_for_each_entry_safe(rpool, tmp, &gpucg->rpools, cg_node)
+ free_cg_rpool_locked(rpool);
+ mutex_unlock(&gpucg_mutex);
+
+ kfree(gpucg);
+}
+
+static struct cgroup_subsys_state *
+gpucg_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+ struct gpucg *gpucg, *parent;
+
+ gpucg = kzalloc(sizeof(struct gpucg), GFP_KERNEL);
+ if (!gpucg)
+ return ERR_PTR(-ENOMEM);
+
+ parent = css_to_gpucg(parent_css);
+ if (!parent)
+ root_gpucg = gpucg;
+
+ INIT_LIST_HEAD(&gpucg->rpools);
+
+ return &gpucg->css;
+}
+
+static struct gpucg_resource_pool *find_cg_rpool_locked(
+ struct gpucg *cg,
+ struct gpucg_device *device)
+{
+ struct gpucg_resource_pool *pool;
+
+ lockdep_assert_held(&gpucg_mutex);
+
+ list_for_each_entry(pool, &cg->rpools, cg_node)
+ if (pool->device == device)
+ return pool;
+
+ return NULL;
+}
+
+static struct gpucg_resource_pool *init_cg_rpool(struct gpucg *cg,
+ struct gpucg_device *device)
+{
+ struct gpucg_resource_pool *rpool = kzalloc(sizeof(*rpool),
+ GFP_KERNEL);
+ if (!rpool)
+ return ERR_PTR(-ENOMEM);
+
+ rpool->device = device;
+
+ page_counter_init(&rpool->total, NULL);
+ INIT_LIST_HEAD(&rpool->cg_node);
+ INIT_LIST_HEAD(&rpool->dev_node);
+ list_add_tail(&rpool->cg_node, &cg->rpools);
+ list_add_tail(&rpool->dev_node, &device->rpools);
+
+ return rpool;
+}
+
+/**
+ * get_cg_rpool_locked - find the resource pool for the specified device and
+ * specified cgroup. If the resource pool does not exist for the cg, it is
+ * created in a hierarchical manner in the cgroup and its ancestor cgroups who
+ * do not already have a resource pool entry for the device.
+ *
+ * @cg: The cgroup to find the resource pool for.
+ * @device: The device associated with the returned resource pool.
+ *
+ * Return: return resource pool entry corresponding to the specified device in
+ * the specified cgroup (hierarchically creating them if not existing already).
+ *
+ */
+static struct gpucg_resource_pool *
+get_cg_rpool_locked(struct gpucg *cg, struct gpucg_device *device)
+{
+ struct gpucg *parent_cg, *p, *stop_cg;
+ struct gpucg_resource_pool *rpool, *tmp_rpool;
+ struct gpucg_resource_pool *parent_rpool = NULL, *leaf_rpool = NULL;
+
+ rpool = find_cg_rpool_locked(cg, device);
+ if (rpool)
+ return rpool;
+
+ stop_cg = cg;
+ do {
+ rpool = init_cg_rpool(stop_cg, device);
+ if (IS_ERR(rpool))
+ goto err;
+
+ if (!leaf_rpool)
+ leaf_rpool = rpool;
+
+ stop_cg = gpucg_parent(stop_cg);
+ if (!stop_cg)
+ break;
+
+ rpool = find_cg_rpool_locked(stop_cg, device);
+ } while (!rpool);
+
+ /*
+ * Re-initialize page counters of all rpools created in this invocation
+ * to enable hierarchical charging.
+ * stop_cg is the first ancestor cg who already had a resource pool for
+ * the device. It can also be NULL if no ancestors had a pre-existing
+ * resource pool for the device before this invocation.
+ */
+ rpool = leaf_rpool;
+ for (p = cg; p != stop_cg; p = parent_cg) {
+ parent_cg = gpucg_parent(p);
+ if (!parent_cg)
+ break;
+ parent_rpool = find_cg_rpool_locked(parent_cg, device);
+ page_counter_init(&rpool->total, &parent_rpool->total);
+
+ rpool = parent_rpool;
+ }
+
+ return leaf_rpool;
+err:
+ for (p = cg; p != stop_cg; p = gpucg_parent(p)) {
+ tmp_rpool = find_cg_rpool_locked(p, device);
+ free_cg_rpool_locked(tmp_rpool);
+ }
+ return rpool;
+}
+
+/**
+ * gpucg_try_charge - charge memory to the specified gpucg and gpucg_device.
+ * Caller must hold a reference to @gpucg obtained through gpucg_get(). The size
+ * of the memory is rounded up to be a multiple of the page size.
+ *
+ * @gpucg: The gpu cgroup to charge the memory to.
+ * @device: The device to charge the memory to.
+ * @usage: size of memory to charge in bytes.
+ *
+ * Return: returns 0 if the charging is successful and otherwise returns an
+ * error code.
+ */
+int gpucg_try_charge(struct gpucg *gpucg, struct gpucg_device *device, u64 usage)
+{
+ struct page_counter *counter;
+ u64 nr_pages;
+ struct gpucg_resource_pool *rp;
+ int ret = 0;
+
+ mutex_lock(&gpucg_mutex);
+ rp = get_cg_rpool_locked(gpucg, device);
+ /*
+ * gpucg_mutex can be unlocked here, rp will stay valid until gpucg is
+ * freed and the caller is holding a reference to the gpucg.
+ */
+ mutex_unlock(&gpucg_mutex);
+
+ if (IS_ERR(rp))
+ return PTR_ERR(rp);
+
+ nr_pages = PAGE_ALIGN(usage) >> PAGE_SHIFT;
+ if (page_counter_try_charge(&rp->total, nr_pages, &counter))
+ css_get_many(&gpucg->css, nr_pages);
+ else
+ ret = -ENOMEM;
+
+ return ret;
+}
+
+/**
+ * gpucg_uncharge - uncharge memory from the specified gpucg and gpucg_device.
+ * The caller must hold a reference to @gpucg obtained through gpucg_get().
+ *
+ * @gpucg: The gpu cgroup to uncharge the memory from.
+ * @device: The device to uncharge the memory from.
+ * @usage: size of memory to uncharge in bytes.
+ */
+void gpucg_uncharge(struct gpucg *gpucg, struct gpucg_device *device, u64 usage)
+{
+ u64 nr_pages;
+ struct gpucg_resource_pool *rp;
+
+ mutex_lock(&gpucg_mutex);
+ rp = find_cg_rpool_locked(gpucg, device);
+ /*
+ * gpucg_mutex can be unlocked here, rp will stay valid until gpucg is
+ * freed and there are active refs on gpucg.
+ */
+ mutex_unlock(&gpucg_mutex);
+
+ if (unlikely(!rp)) {
+ pr_err("Resource pool not found, incorrect charge/uncharge ordering?\n");
+ return;
+ }
+
+ nr_pages = PAGE_ALIGN(usage) >> PAGE_SHIFT;
+ page_counter_uncharge(&rp->total, nr_pages);
+ css_put_many(&gpucg->css, nr_pages);
+}
+
+/**
+ * gpucg_register_device - Registers a device for memory accounting using the
+ * GPU cgroup controller.
+ *
+ * @device: The device to register for memory accounting.
+ * @name: Pointer to a string literal to denote the name of the device.
+ *
+ * Both @device andd @name must remain valid.
+ */
+void gpucg_register_device(struct gpucg_device *device, const char *name)
+{
+ if (!device)
+ return;
+
+ INIT_LIST_HEAD(&device->dev_node);
+ INIT_LIST_HEAD(&device->rpools);
+
+ mutex_lock(&gpucg_mutex);
+ list_add_tail(&device->dev_node, &gpucg_devices);
+ mutex_unlock(&gpucg_mutex);
+
+ device->name = name;
+}
+
+static int gpucg_resource_show(struct seq_file *sf, void *v)
+{
+ struct gpucg_resource_pool *rpool;
+ struct gpucg *cg = css_to_gpucg(seq_css(sf));
+
+ mutex_lock(&gpucg_mutex);
+ list_for_each_entry(rpool, &cg->rpools, cg_node) {
+ seq_printf(sf, "%s %lu\n", rpool->device->name,
+ page_counter_read(&rpool->total) * PAGE_SIZE);
+ }
+ mutex_unlock(&gpucg_mutex);
+
+ return 0;
+}
+
+struct cftype files[] = {
+ {
+ .name = "memory.current",
+ .seq_show = gpucg_resource_show,
+ },
+ { } /* terminate */
+};
+
+struct cgroup_subsys gpu_cgrp_subsys = {
+ .css_alloc = gpucg_css_alloc,
+ .css_free = gpucg_css_free,
+ .early_init = false,
+ .legacy_cftypes = files,
+ .dfl_cftypes = files,
+};
--
2.35.1.265.g69c8d7142f-goog