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%2FkMC7YjVMXv@phenom.ffwll.local/
Signed-off-by: Hridya Valsaraju hridya@google.com --- include/linux/cgroup_gpu.h | 120 +++++++++++++ include/linux/cgroup_subsys.h | 4 + init/Kconfig | 7 + kernel/cgroup/Makefile | 1 + kernel/cgroup/gpu.c | 305 ++++++++++++++++++++++++++++++++++ 5 files changed, 437 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..0ac303ce6179 --- /dev/null +++ b/include/linux/cgroup_gpu.h @@ -0,0 +1,120 @@ +/* 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 pool 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 cd23faa163d1..408910b21387 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -990,6 +990,13 @@ 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..b171fae06b0d --- /dev/null +++ b/kernel/cgroup/gpu.c @@ -0,0 +1,305 @@ +// 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/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, +};