From: Hridya Valsaraju hridya@google.com

This patch adds a proposal for a new GPU cgroup controller for accounting/limiting GPU and GPU-related memory allocations. The proposed controller is based on the DRM cgroup controller[1] and follows the design of the RDMA cgroup controller.

The new cgroup controller would: * Allow setting per-cgroup limits on the total size of buffers charged to it. * Allow setting per-device limits on the total size of buffers allocated by device within a cgroup. * Expose a per-device/allocator breakdown of the buffers charged to a cgroup.

The prototype in the following patches is only for memory accounting using the GPU cgroup controller and does not implement limit setting.

[1]: https://lore.kernel.org/amd-gfx/20210126214626.16260-1-brian.welty@intel.com...

Signed-off-by: Hridya Valsaraju hridya@google.com Signed-off-by: T.J. Mercier tjmercier@google.com

--- v3 changes Remove Upstreaming Plan from gpu-cgroup.rst per John Stultz.

Use more common dual author commit message format per John Stultz. --- Documentation/gpu/rfc/gpu-cgroup.rst | 183 +++++++++++++++++++++++++++ Documentation/gpu/rfc/index.rst | 4 + 2 files changed, 187 insertions(+) create mode 100644 Documentation/gpu/rfc/gpu-cgroup.rst

diff --git a/Documentation/gpu/rfc/gpu-cgroup.rst b/Documentation/gpu/rfc/gpu-cgroup.rst new file mode 100644 index 000000000000..5b40d5518a5e --- /dev/null +++ b/Documentation/gpu/rfc/gpu-cgroup.rst @@ -0,0 +1,183 @@ +=================================== +GPU cgroup controller +=================================== + +Goals +===== +This document intends to outline a plan to create a cgroup v2 controller subsystem +for the per-cgroup accounting of device and system memory allocated by the GPU +and related subsystems. + +The new cgroup controller would: + +* Allow setting per-cgroup limits on the total size of buffers charged to it. + +* Allow setting per-device limits on the total size of buffers allocated by a + device/allocator within a cgroup. + +* Expose a per-device/allocator breakdown of the buffers charged to a cgroup. + +Alternatives Considered +======================= + +The following alternatives were considered: + +The memory cgroup controller +____________________________ + +1. As was noted in [1], memory accounting provided by the GPU cgroup +controller is not a good fit for integration into memcg due to the +differences in how accounting is performed. It implements a mechanism +for the allocator attribution of GPU and GPU-related memory by +charging each buffer to the cgroup of the process on behalf of which +the memory was allocated. The buffer stays charged to the cgroup until +it is freed regardless of whether the process retains any references +to it. On the other hand, the memory cgroup controller offers a more +fine-grained charging and uncharging behavior depending on the kind of +page being accounted. + +2. Memcg performs accounting in units of pages. In the DMA-BUF buffer sharing model, +a process takes a reference to the entire buffer(hence keeping it alive) even if +it is only accessing parts of it. Therefore, per-page memory tracking for DMA-BUF +memory accounting would only introduce additional overhead without any benefits. + +[1]: https://patchwork.kernel.org/project/dri-devel/cover/20190501140438.9506-1-b... + +Userspace service to keep track of buffer allocations and releases +__________________________________________________________________ + +1. There is no way for a userspace service to intercept all allocations and releases. +2. In case the process gets killed or restarted, we lose all accounting so far. + +UAPI +==== +When enabled, the new cgroup controller would create the following files in every cgroup. + +:: + + gpu.memory.current (R) + gpu.memory.max (R/W) + +gpu.memory.current is a read-only file and would contain per-device memory allocations +in a key-value format where key is a string representing the device name +and the value is the size of memory charged to the device in the cgroup in bytes. + +For example: + +:: + + cat /sys/kernel/fs/cgroup1/gpu.memory.current + dev1 4194304 + dev2 4194304 + +The string key for each device is set by the device driver when the device registers +with the GPU cgroup controller to participate in resource accounting(see section +'Design and Implementation' for more details). + +gpu.memory.max is a read/write file. It would show the current total +size limits on memory usage for the cgroup and the limits on total memory usage +for each allocator/device. + +Setting a total limit for a cgroup can be done as follows: + +:: + + echo “total 41943040” > /sys/kernel/fs/cgroup1/gpu.memory.max + +Setting a total limit for a particular device/allocator can be done as follows: + +:: + + echo “dev1 4194304” > /sys/kernel/fs/cgroup1/gpu.memory.max + +In this example, 'dev1' is the string key set by the device driver during +registration. + +Design and Implementation +========================= + +The cgroup controller would closely follow the design of the RDMA cgroup controller +subsystem where each cgroup maintains a list of resource pools. +Each resource pool contains a struct device and the counter to track current total, +and the maximum limit set for the device. + +The below code block is a preliminary estimation on how the core kernel data structures +and APIs would look like. + +.. code-block:: c + + /** + * 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; + + /* name to be used as identifier for accounting and limit setting */ + const char *name; + }; + + 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; + }; + + /** + * gpucg_register_device - Registers a device for memory accounting using the + * GPU cgroup controller. + * + * @device: The device to register for memory accounting. Must remain valid + * after registration. + * @name: Pointer to a string literal to denote the name of the device. + */ + void gpucg_register_device(struct gpucg_device *gpucg_dev, const char *name); + + /** + * gpucg_try_charge - charge memory to the specified gpucg and gpucg_device. + * + * @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); + + /** + * gpucg_uncharge - uncharge memory from the specified gpucg and gpucg_device. + * + * @gpucg: The gpu cgroup to uncharge the memory from. + * @device: The device to charge the memory from. + * @usage: size of memory to uncharge in bytes. + */ + void gpucg_uncharge(struct gpucg *gpucg, struct gpucg_device *device, u64 usage); + +Future Work +=========== +Additional GPU resources can be supported by adding new controller files. diff --git a/Documentation/gpu/rfc/index.rst b/Documentation/gpu/rfc/index.rst index 91e93a705230..0a9bcd94e95d 100644 --- a/Documentation/gpu/rfc/index.rst +++ b/Documentation/gpu/rfc/index.rst @@ -23,3 +23,7 @@ host such documentation: .. toctree::

i915_scheduler.rst + +.. toctree:: + + gpu-cgroup.rst

This patch uses the GPU cgroup charge/uncharge APIs to charge buffers allocated by any DMA-BUF exporter that exports a buffer with a GPU cgroup device association.

By doing so, it becomes possible to track who allocated/exported a DMA-BUF even after the allocating process drops all references to a buffer.

Originally-by: Hridya Valsaraju hridya@google.com Signed-off-by: T.J. Mercier tjmercier@google.com

--- v4 changes Fix uninitialized return code error for dmabuf_try_charge error case.

v3 changes Use more common dual author commit message format per John Stultz.

v2 changes Move dma-buf cgroup charging/uncharging from a dma_buf_op defined by every heap to a single dma-buf function for all heaps per Daniel Vetter and Christian König. --- drivers/dma-buf/dma-buf.c | 58 +++++++++++++++++++++++++++++++++++++++ include/linux/dma-buf.h | 20 ++++++++++++-- 2 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 602b12d7470d..1ee5c60d3d6d 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -56,6 +56,53 @@ static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen) dentry->d_name.name, ret > 0 ? name : ""); }

+#ifdef CONFIG_CGROUP_GPU +static inline struct gpucg_device * +exp_info_gpucg_dev(const struct dma_buf_export_info *exp_info) +{ + return exp_info->gpucg_dev; +} + +static int dmabuf_try_charge(struct dma_buf *dmabuf, + struct gpucg_device *gpucg_dev) +{ + int ret; + + dmabuf->gpucg = gpucg_get(current); + dmabuf->gpucg_dev = gpucg_dev; + + ret = gpucg_try_charge(dmabuf->gpucg, dmabuf->gpucg_dev, dmabuf->size); + if (ret) { + gpucg_put(dmabuf->gpucg); + dmabuf->gpucg = NULL; + dmabuf->gpucg_dev = NULL; + } + return ret; +} + +static void dmabuf_uncharge(struct dma_buf *dmabuf) +{ + if (dmabuf->gpucg && dmabuf->gpucg_dev) { + gpucg_uncharge(dmabuf->gpucg, dmabuf->gpucg_dev, dmabuf->size); + gpucg_put(dmabuf->gpucg); + } +} +#else /* CONFIG_CGROUP_GPU */ +static inline struct gpucg_device *exp_info_gpucg_dev( +const struct dma_buf_export_info *exp_info) +{ + return NULL; +} + +static inline int dmabuf_try_charge(struct dma_buf *dmabuf, + struct gpucg_device *gpucg_dev)) +{ + return 0; +} + +static inline void dmabuf_uncharge(struct dma_buf *dmabuf) {} +#endif /* CONFIG_CGROUP_GPU */ + static void dma_buf_release(struct dentry *dentry) { struct dma_buf *dmabuf; @@ -79,6 +126,8 @@ static void dma_buf_release(struct dentry *dentry) if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) dma_resv_fini(dmabuf->resv);

+ dmabuf_uncharge(dmabuf); + WARN_ON(!list_empty(&dmabuf->attachments)); module_put(dmabuf->owner); kfree(dmabuf->name); @@ -484,6 +533,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) { struct dma_buf *dmabuf; struct dma_resv *resv = exp_info->resv; + struct gpucg_device *gpucg_dev = exp_info_gpucg_dev(exp_info); struct file *file; size_t alloc_size = sizeof(struct dma_buf); int ret; @@ -534,6 +584,12 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) } dmabuf->resv = resv;

+ if (gpucg_dev) { + ret = dmabuf_try_charge(dmabuf, gpucg_dev); + if (ret) + goto err_charge; + } + file = dma_buf_getfile(dmabuf, exp_info->flags); if (IS_ERR(file)) { ret = PTR_ERR(file); @@ -565,6 +621,8 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) file->f_path.dentry->d_fsdata = NULL; fput(file); err_dmabuf: + dmabuf_uncharge(dmabuf); +err_charge: kfree(dmabuf); err_module: module_put(exp_info->owner); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 7ab50076e7a6..742f29c3daaf 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -13,6 +13,7 @@ #ifndef __DMA_BUF_H__ #define __DMA_BUF_H__

+#include <linux/cgroup_gpu.h> #include <linux/dma-buf-map.h> #include <linux/file.h> #include <linux/err.h> @@ -303,7 +304,7 @@ struct dma_buf { /** * @size: * - * Size of the buffer; invariant over the lifetime of the buffer. + * Size of the buffer in bytes; invariant over the lifetime of the buffer. */ size_t size;

@@ -453,6 +454,17 @@ struct dma_buf { struct dma_buf *dmabuf; } *sysfs_entry; #endif + +#ifdef CONFIG_CGROUP_GPU + /** @gpucg: Pointer to the cgroup this buffer currently belongs to. */ + struct gpucg *gpucg; + + /** @gpucg_dev: + * + * Pointer to the cgroup GPU device whence this buffer originates. + */ + struct gpucg_device *gpucg_dev; +#endif };

/** @@ -529,9 +541,10 @@ struct dma_buf_attachment { * @exp_name: name of the exporter - useful for debugging. * @owner: pointer to exporter module - used for refcounting kernel module * @ops: Attach allocator-defined dma buf ops to the new buffer - * @size: Size of the buffer - invariant over the lifetime of the buffer + * @size: Size of the buffer in bytes - invariant over the lifetime of the buffer * @flags: mode flags for the file * @resv: reservation-object, NULL to allocate default one + * @gpucg_dev: pointer to the gpu cgroup device this buffer belongs to * @priv: Attach private data of allocator to this buffer * * This structure holds the information required to export the buffer. Used @@ -544,6 +557,9 @@ struct dma_buf_export_info { size_t size; int flags; struct dma_resv *resv; +#ifdef CONFIG_CGROUP_GPU + struct gpucg_device *gpucg_dev; +#endif void *priv; };

From: Hridya Valsaraju hridya@google.com

This patch introduces a buffer flag BINDER_BUFFER_FLAG_SENDER_NO_NEED that a process sending an fd array to another process over binder IPC can set to relinquish ownership of the fds being sent for memory accounting purposes. If the flag is found to be set during the fd array translation and the fd is for a DMA-BUF, the buffer is uncharged from the sender's cgroup and charged to the receiving process's cgroup instead.

It is up to the sending process to ensure that it closes the fds regardless of whether the transfer failed or succeeded.

Most graphics shared memory allocations in Android are done by the graphics allocator HAL process. On requests from clients, the HAL process allocates memory and sends the fds to the clients over binder IPC. The graphics allocator HAL will not retain any references to the buffers. When the HAL sets the BINDER_BUFFER_FLAG_SENDER_NO_NEED for fd arrays holding DMA-BUF fds, the gpu cgroup controller will be able to correctly charge the buffers to the client processes instead of the graphics allocator HAL.

Since this is a new feature exposed to userspace, the kernel and userspace must be compatible for the accounting to work for transfers. In all cases the allocation and transport of DMA buffers via binder will succeed, but only when both the kernel supports, and userspace depends on this feature will the transfer accounting work. The possible scenarios are detailed below:

1. new kernel + old userspace The kernel supports the feature but userspace does not use it. The old userspace won't mount the new cgroup controller, accounting is not performed, charge is not transferred.

2. old kernel + new userspace The new cgroup controller is not supported by the kernel, accounting is not performed, charge is not transferred.

3. old kernel + old userspace Same as #2

4. new kernel + new userspace Cgroup is mounted, feature is supported and used.

Signed-off-by: Hridya Valsaraju hridya@google.com Signed-off-by: T.J. Mercier tjmercier@google.com

--- v3 changes Remove android from title per Todd Kjos.

Use more common dual author commit message format per John Stultz.

Include details on behavior for all combinations of kernel/userspace versions in changelog (thanks Suren Baghdasaryan) per Greg Kroah-Hartman.

v2 changes Move dma-buf cgroup charge transfer from a dma_buf_op defined by every heap to a single dma-buf function for all heaps per Daniel Vetter and Christian König. --- drivers/android/binder.c | 26 ++++++++++++++++++++++++++ include/uapi/linux/android/binder.h | 1 + 2 files changed, 27 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 8351c5638880..4357d2efc8e1 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -42,6 +42,7 @@

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

+#include <linux/dma-buf.h> #include <linux/fdtable.h> #include <linux/file.h> #include <linux/freezer.h> @@ -2482,8 +2483,10 @@ static int binder_translate_fd_array(struct list_head *pf_head, { binder_size_t fdi, fd_buf_size; binder_size_t fda_offset; + bool transfer_gpu_charge = false; const void __user *sender_ufda_base; struct binder_proc *proc = thread->proc; + struct binder_proc *target_proc = t->to_proc; int ret;

fd_buf_size = sizeof(u32) * fda->num_fds; @@ -2521,8 +2524,15 @@ static int binder_translate_fd_array(struct list_head *pf_head, if (ret) return ret;

+ if (IS_ENABLED(CONFIG_CGROUP_GPU) && + parent->flags & BINDER_BUFFER_FLAG_SENDER_NO_NEED) + transfer_gpu_charge = true; + for (fdi = 0; fdi < fda->num_fds; fdi++) { u32 fd; + struct dma_buf *dmabuf; + struct gpucg *gpucg; + binder_size_t offset = fda_offset + fdi * sizeof(fd); binder_size_t sender_uoffset = fdi * sizeof(fd);

@@ -2532,6 +2542,22 @@ static int binder_translate_fd_array(struct list_head *pf_head, in_reply_to); if (ret) return ret > 0 ? -EINVAL : ret; + + if (!transfer_gpu_charge) + continue; + + dmabuf = dma_buf_get(fd); + if (IS_ERR(dmabuf)) + continue; + + gpucg = gpucg_get(target_proc->tsk); + ret = dma_buf_transfer_charge(dmabuf, gpucg); + if (ret) { + pr_warn("%d:%d Unable to transfer DMA-BUF fd charge to %d", + proc->pid, thread->pid, target_proc->pid); + gpucg_put(gpucg); + } + dma_buf_put(dmabuf); } return 0; } diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h index 3246f2c74696..169fd5069a1a 100644 --- a/include/uapi/linux/android/binder.h +++ b/include/uapi/linux/android/binder.h @@ -137,6 +137,7 @@ struct binder_buffer_object {

enum { BINDER_BUFFER_FLAG_HAS_PARENT = 0x01, + BINDER_BUFFER_FLAG_SENDER_NO_NEED = 0x02, };

/* struct binder_fd_array_object - object describing an array of fds in a buffer

This test verifies that the cgroup GPU memory charge is transferred correctly when a dmabuf is passed between processes in two different cgroups and the sender specifies BINDER_BUFFER_FLAG_SENDER_NO_NEED in the binder transaction data containing the dmabuf file descriptor.

Signed-off-by: T.J. Mercier tjmercier@google.com --- v4 changes Skip test if not run as root per Shuah Khan.

Add better logging for abnormal child termination per Shuah Khan. --- .../selftests/drivers/android/binder/Makefile | 8 + .../drivers/android/binder/binder_util.c | 254 +++++++++ .../drivers/android/binder/binder_util.h | 32 ++ .../selftests/drivers/android/binder/config | 4 + .../binder/test_dmabuf_cgroup_transfer.c | 484 ++++++++++++++++++ 5 files changed, 782 insertions(+) create mode 100644 tools/testing/selftests/drivers/android/binder/Makefile create mode 100644 tools/testing/selftests/drivers/android/binder/binder_util.c create mode 100644 tools/testing/selftests/drivers/android/binder/binder_util.h create mode 100644 tools/testing/selftests/drivers/android/binder/config create mode 100644 tools/testing/selftests/drivers/android/binder/test_dmabuf_cgroup_transfer.c

diff --git a/tools/testing/selftests/drivers/android/binder/Makefile b/tools/testing/selftests/drivers/android/binder/Makefile new file mode 100644 index 000000000000..726439d10675 --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 +CFLAGS += -Wall + +TEST_GEN_PROGS = test_dmabuf_cgroup_transfer + +include ../../../lib.mk + +$(OUTPUT)/test_dmabuf_cgroup_transfer: ../../../cgroup/cgroup_util.c binder_util.c diff --git a/tools/testing/selftests/drivers/android/binder/binder_util.c b/tools/testing/selftests/drivers/android/binder/binder_util.c new file mode 100644 index 000000000000..c9dcf5b9d42b --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/binder_util.c @@ -0,0 +1,254 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "binder_util.h" + +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/mount.h> + +#include <linux/limits.h> +#include <linux/android/binder.h> +#include <linux/android/binderfs.h> + +static const size_t BINDER_MMAP_SIZE = 64 * 1024; + +static void binderfs_unmount(const char *mountpoint) +{ + if (umount2(mountpoint, MNT_DETACH)) + fprintf(stderr, "Failed to unmount binderfs at %s: %s\n", + mountpoint, strerror(errno)); + else + fprintf(stderr, "Binderfs unmounted: %s\n", mountpoint); + + if (rmdir(mountpoint)) + fprintf(stderr, "Failed to remove binderfs mount %s: %s\n", + mountpoint, strerror(errno)); + else + fprintf(stderr, "Binderfs mountpoint destroyed: %s\n", mountpoint); +} + +struct binderfs_ctx create_binderfs(const char *name) +{ + int fd, ret, saved_errno; + struct binderfs_device device = { 0 }; + struct binderfs_ctx ctx = { 0 }; + + /* + * P_tmpdir is set to "/tmp/" on Android platforms where Binder is most + * commonly used, but this path does not actually exist on Android. We + * will first try using "/data/local/tmp" and fallback to P_tmpdir if + * that fails for non-Android platforms. + */ + static const char tmpdir[] = "/data/local/tmp"; + static const size_t MAX_TMPDIR_SIZE = + sizeof(tmpdir) > sizeof(P_tmpdir) ? + sizeof(tmpdir) : sizeof(P_tmpdir); + static const char template[] = "/binderfs_XXXXXX"; + + char *mkdtemp_result; + char binderfs_mntpt[MAX_TMPDIR_SIZE + sizeof(template)]; + char device_path[MAX_TMPDIR_SIZE + sizeof(template) + BINDERFS_MAX_NAME]; + + snprintf(binderfs_mntpt, sizeof(binderfs_mntpt), "%s%s", tmpdir, template); + + mkdtemp_result = mkdtemp(binderfs_mntpt); + if (mkdtemp_result == NULL) { + fprintf(stderr, "Failed to create binderfs mountpoint at %s: %s.\n", + binderfs_mntpt, strerror(errno)); + fprintf(stderr, "Trying fallback mountpoint...\n"); + snprintf(binderfs_mntpt, sizeof(binderfs_mntpt), "%s%s", P_tmpdir, template); + if (mkdtemp(binderfs_mntpt) == NULL) { + fprintf(stderr, "Failed to create binderfs mountpoint at %s: %s\n", + binderfs_mntpt, strerror(errno)); + return ctx; + } + } + fprintf(stderr, "Binderfs mountpoint created at %s\n", binderfs_mntpt); + + if (mount(NULL, binderfs_mntpt, "binder", 0, 0)) { + perror("Could not mount binderfs"); + rmdir(binderfs_mntpt); + return ctx; + } + fprintf(stderr, "Binderfs mounted at %s\n", binderfs_mntpt); + + strncpy(device.name, name, sizeof(device.name)); + snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt); + fd = open(device_path, O_RDONLY | O_CLOEXEC); + if (!fd) { + perror("Failed to open binder-control device"); + binderfs_unmount(binderfs_mntpt); + return ctx; + } + + ret = ioctl(fd, BINDER_CTL_ADD, &device); + saved_errno = errno; + close(fd); + errno = saved_errno; + if (ret) { + perror("Failed to allocate new binder device"); + binderfs_unmount(binderfs_mntpt); + return ctx; + } + + fprintf(stderr, "Allocated new binder device with major %d, minor %d, and name %s at %s\n", + device.major, device.minor, device.name, binderfs_mntpt); + + ctx.name = strdup(name); + ctx.mountpoint = strdup(binderfs_mntpt); + return ctx; +} + +void destroy_binderfs(struct binderfs_ctx *ctx) +{ + char path[PATH_MAX]; + + snprintf(path, sizeof(path), "%s/%s", ctx->mountpoint, ctx->name); + + if (unlink(path)) + fprintf(stderr, "Failed to unlink binder device %s: %s\n", path, strerror(errno)); + else + fprintf(stderr, "Destroyed binder %s at %s\n", ctx->name, ctx->mountpoint); + + binderfs_unmount(ctx->mountpoint); + + free(ctx->name); + free(ctx->mountpoint); +} + +struct binder_ctx open_binder(struct binderfs_ctx *bfs_ctx) +{ + struct binder_ctx ctx = {.fd = -1, .memory = NULL}; + char path[PATH_MAX]; + + snprintf(path, sizeof(path), "%s/%s", bfs_ctx->mountpoint, bfs_ctx->name); + ctx.fd = open(path, O_RDWR | O_NONBLOCK | O_CLOEXEC); + if (ctx.fd < 0) { + fprintf(stderr, "Error opening binder device %s: %s\n", path, strerror(errno)); + return ctx; + } + + ctx.memory = mmap(NULL, BINDER_MMAP_SIZE, PROT_READ, MAP_SHARED, ctx.fd, 0); + if (ctx.memory == NULL) { + perror("Error mapping binder memory"); + close(ctx.fd); + ctx.fd = -1; + } + + return ctx; +} + +void close_binder(struct binder_ctx *ctx) +{ + if (munmap(ctx->memory, BINDER_MMAP_SIZE)) + perror("Failed to unmap binder memory"); + ctx->memory = NULL; + + if (close(ctx->fd)) + perror("Failed to close binder"); + ctx->fd = -1; +} + +int become_binder_context_manager(int binder_fd) +{ + return ioctl(binder_fd, BINDER_SET_CONTEXT_MGR, 0); +} + +int do_binder_write_read(int binder_fd, void *writebuf, binder_size_t writesize, + void *readbuf, binder_size_t readsize) +{ + int err; + struct binder_write_read bwr = { + .write_buffer = (binder_uintptr_t)writebuf, + .write_size = writesize, + .read_buffer = (binder_uintptr_t)readbuf, + .read_size = readsize + }; + + do { + if (ioctl(binder_fd, BINDER_WRITE_READ, &bwr) >= 0) + err = 0; + else + err = -errno; + } while (err == -EINTR); + + if (err < 0) { + perror("BINDER_WRITE_READ"); + return -1; + } + + if (bwr.write_consumed < writesize) { + fprintf(stderr, "Binder did not consume full write buffer %llu %llu\n", + bwr.write_consumed, writesize); + return -1; + } + + return bwr.read_consumed; +} + +static const char *reply_string(int cmd) +{ + switch (cmd) { + case BR_ERROR: + return("BR_ERROR"); + case BR_OK: + return("BR_OK"); + case BR_TRANSACTION_SEC_CTX: + return("BR_TRANSACTION_SEC_CTX"); + case BR_TRANSACTION: + return("BR_TRANSACTION"); + case BR_REPLY: + return("BR_REPLY"); + case BR_ACQUIRE_RESULT: + return("BR_ACQUIRE_RESULT"); + case BR_DEAD_REPLY: + return("BR_DEAD_REPLY"); + case BR_TRANSACTION_COMPLETE: + return("BR_TRANSACTION_COMPLETE"); + case BR_INCREFS: + return("BR_INCREFS"); + case BR_ACQUIRE: + return("BR_ACQUIRE"); + case BR_RELEASE: + return("BR_RELEASE"); + case BR_DECREFS: + return("BR_DECREFS"); + case BR_ATTEMPT_ACQUIRE: + return("BR_ATTEMPT_ACQUIRE"); + case BR_NOOP: + return("BR_NOOP"); + case BR_SPAWN_LOOPER: + return("BR_SPAWN_LOOPER"); + case BR_FINISHED: + return("BR_FINISHED"); + case BR_DEAD_BINDER: + return("BR_DEAD_BINDER"); + case BR_CLEAR_DEATH_NOTIFICATION_DONE: + return("BR_CLEAR_DEATH_NOTIFICATION_DONE"); + case BR_FAILED_REPLY: + return("BR_FAILED_REPLY"); + case BR_FROZEN_REPLY: + return("BR_FROZEN_REPLY"); + case BR_ONEWAY_SPAM_SUSPECT: + return("BR_ONEWAY_SPAM_SUSPECT"); + default: + return("Unknown"); + }; +} + +int expect_binder_reply(int32_t actual, int32_t expected) +{ + if (actual != expected) { + fprintf(stderr, "Expected %s but received %s\n", + reply_string(expected), reply_string(actual)); + return -1; + } + return 0; +} + diff --git a/tools/testing/selftests/drivers/android/binder/binder_util.h b/tools/testing/selftests/drivers/android/binder/binder_util.h new file mode 100644 index 000000000000..807f5abe987e --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/binder_util.h @@ -0,0 +1,32 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef SELFTEST_BINDER_UTIL_H +#define SELFTEST_BINDER_UTIL_H + +#include <stdint.h> + +#include <linux/android/binder.h> + +struct binderfs_ctx { + char *name; + char *mountpoint; +}; + +struct binder_ctx { + int fd; + void *memory; +}; + +struct binderfs_ctx create_binderfs(const char *name); +void destroy_binderfs(struct binderfs_ctx *ctx); + +struct binder_ctx open_binder(struct binderfs_ctx *bfs_ctx); +void close_binder(struct binder_ctx *ctx); + +int become_binder_context_manager(int binder_fd); + +int do_binder_write_read(int binder_fd, void *writebuf, binder_size_t writesize, + void *readbuf, binder_size_t readsize); + +int expect_binder_reply(int32_t actual, int32_t expected); +#endif diff --git a/tools/testing/selftests/drivers/android/binder/config b/tools/testing/selftests/drivers/android/binder/config new file mode 100644 index 000000000000..fcc5f8f693b3 --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/config @@ -0,0 +1,4 @@ +CONFIG_CGROUP_GPU=y +CONFIG_ANDROID=y +CONFIG_ANDROID_BINDERFS=y +CONFIG_ANDROID_BINDER_IPC=y diff --git a/tools/testing/selftests/drivers/android/binder/test_dmabuf_cgroup_transfer.c b/tools/testing/selftests/drivers/android/binder/test_dmabuf_cgroup_transfer.c new file mode 100644 index 000000000000..586465d7bf6d --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/test_dmabuf_cgroup_transfer.c @@ -0,0 +1,484 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * This test verifies that the cgroup GPU memory charge is transferred correctly + * when a dmabuf is passed between processes in two different cgroups and the + * sender specifies BINDER_BUFFER_FLAG_SENDER_NO_NEED in the binder transaction + * data containing the dmabuf file descriptor. + * + * The gpu_cgroup_dmabuf_transfer test function becomes the binder context + * manager, then forks a child who initiates a transaction with the context + * manager by specifying a target of 0. The context manager reply contains a + * dmabuf file descriptor which was allocated by the gpu_cgroup_dmabuf_transfer + * test function, but should be charged to the child cgroup after the binder + * transaction. + */ + +#include <errno.h> +#include <fcntl.h> +#include <stddef.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/epoll.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/wait.h> + +#include "binder_util.h" +#include "../../../cgroup/cgroup_util.h" +#include "../../../kselftest.h" +#include "../../../kselftest_harness.h" + +#include <linux/limits.h> +#include <linux/dma-heap.h> +#include <linux/android/binder.h> + +#define UNUSED(x) ((void)(x)) + +static const unsigned int BINDER_CODE = 8675309; /* Any number will work here */ + +struct cgroup_ctx { + char *root; + char *source; + char *dest; +}; + +void destroy_cgroups(struct __test_metadata *_metadata, struct cgroup_ctx *ctx) +{ + if (ctx->source != NULL) { + TH_LOG("Destroying cgroup: %s", ctx->source); + rmdir(ctx->source); + free(ctx->source); + } + + if (ctx->dest != NULL) { + TH_LOG("Destroying cgroup: %s", ctx->dest); + rmdir(ctx->dest); + free(ctx->dest); + } + + free(ctx->root); + ctx->root = ctx->source = ctx->dest = NULL; +} + +struct cgroup_ctx create_cgroups(struct __test_metadata *_metadata) +{ + struct cgroup_ctx ctx = {0}; + char root[PATH_MAX], *tmp; + static const char template[] = "/gpucg_XXXXXX"; + + if (cg_find_unified_root(root, sizeof(root))) { + TH_LOG("Could not find cgroups root"); + return ctx; + } + + if (cg_read_strstr(root, "cgroup.controllers", "gpu")) { + TH_LOG("Could not find GPU controller"); + return ctx; + } + + if (cg_write(root, "cgroup.subtree_control", "+gpu")) { + TH_LOG("Could not enable GPU controller"); + return ctx; + } + + ctx.root = strdup(root); + + snprintf(root, sizeof(root), "%s/%s", ctx.root, template); + tmp = mkdtemp(root); + if (tmp == NULL) { + TH_LOG("%s - Could not create source cgroup", strerror(errno)); + destroy_cgroups(_metadata, &ctx); + return ctx; + } + ctx.source = strdup(tmp); + + snprintf(root, sizeof(root), "%s/%s", ctx.root, template); + tmp = mkdtemp(root); + if (tmp == NULL) { + TH_LOG("%s - Could not create destination cgroup", strerror(errno)); + destroy_cgroups(_metadata, &ctx); + return ctx; + } + ctx.dest = strdup(tmp); + + TH_LOG("Created cgroups: %s %s", ctx.source, ctx.dest); + + return ctx; +} + +int dmabuf_heap_alloc(int fd, size_t len, int *dmabuf_fd) +{ + struct dma_heap_allocation_data data = { + .len = len, + .fd = 0, + .fd_flags = O_RDONLY | O_CLOEXEC, + .heap_flags = 0, + }; + int ret; + + if (!dmabuf_fd) + return -EINVAL; + + ret = ioctl(fd, DMA_HEAP_IOCTL_ALLOC, &data); + if (ret < 0) + return ret; + *dmabuf_fd = (int)data.fd; + return ret; +} + +/* The system heap is known to export dmabufs with support for cgroup tracking */ +int alloc_dmabuf_from_system_heap(struct __test_metadata *_metadata, size_t bytes) +{ + int heap_fd = -1, dmabuf_fd = -1; + static const char * const heap_path = "/dev/dma_heap/system"; + + heap_fd = open(heap_path, O_RDONLY); + if (heap_fd < 0) { + TH_LOG("%s - open %s failed!\n", strerror(errno), heap_path); + return -1; + } + + if (dmabuf_heap_alloc(heap_fd, bytes, &dmabuf_fd)) + TH_LOG("dmabuf allocation failed! - %s", strerror(errno)); + close(heap_fd); + + return dmabuf_fd; +} + +int binder_request_dmabuf(int binder_fd) +{ + int ret; + + /* + * We just send an empty binder_buffer_object to initiate a transaction + * with the context manager, who should respond with a single dmabuf + * inside a binder_fd_array_object. + */ + + struct binder_buffer_object bbo = { + .hdr.type = BINDER_TYPE_PTR, + .flags = 0, + .buffer = 0, + .length = 0, + .parent = 0, /* No parent */ + .parent_offset = 0 /* No parent */ + }; + + binder_size_t offsets[] = {0}; + + struct { + int32_t cmd; + struct binder_transaction_data btd; + } __attribute__((packed)) bc = { + .cmd = BC_TRANSACTION, + .btd = { + .target = { 0 }, + .cookie = 0, + .code = BINDER_CODE, + .flags = TF_ACCEPT_FDS, /* We expect a FDA in the reply */ + .data_size = sizeof(bbo), + .offsets_size = sizeof(offsets), + .data.ptr = { + (binder_uintptr_t)&bbo, + (binder_uintptr_t)offsets + } + }, + }; + + struct { + int32_t reply_noop; + } __attribute__((packed)) br; + + ret = do_binder_write_read(binder_fd, &bc, sizeof(bc), &br, sizeof(br)); + if (ret >= sizeof(br) && expect_binder_reply(br.reply_noop, BR_NOOP)) { + return -1; + } else if (ret < sizeof(br)) { + fprintf(stderr, "Not enough bytes in binder reply %d\n", ret); + return -1; + } + return 0; +} + +int send_dmabuf_reply(int binder_fd, struct binder_transaction_data *tr, int dmabuf_fd) +{ + int ret; + /* + * The trailing 0 is to achieve the necessary alignment for the binder + * buffer_size. + */ + int fdarray[] = { dmabuf_fd, 0 }; + + struct binder_buffer_object bbo = { + .hdr.type = BINDER_TYPE_PTR, + .flags = BINDER_BUFFER_FLAG_SENDER_NO_NEED, + .buffer = (binder_uintptr_t)fdarray, + .length = sizeof(fdarray), + .parent = 0, /* No parent */ + .parent_offset = 0 /* No parent */ + }; + + struct binder_fd_array_object bfdao = { + .hdr.type = BINDER_TYPE_FDA, + .num_fds = 1, + .parent = 0, /* The binder_buffer_object */ + .parent_offset = 0 /* FDs follow immediately */ + }; + + uint64_t sz = sizeof(fdarray); + uint8_t data[sizeof(sz) + sizeof(bbo) + sizeof(bfdao)]; + binder_size_t offsets[] = {sizeof(sz), sizeof(sz)+sizeof(bbo)}; + + memcpy(data, &sz, sizeof(sz)); + memcpy(data + sizeof(sz), &bbo, sizeof(bbo)); + memcpy(data + sizeof(sz) + sizeof(bbo), &bfdao, sizeof(bfdao)); + + struct { + int32_t cmd; + struct binder_transaction_data_sg btd; + } __attribute__((packed)) bc = { + .cmd = BC_REPLY_SG, + .btd.transaction_data = { + .target = { tr->target.handle }, + .cookie = tr->cookie, + .code = BINDER_CODE, + .flags = 0, + .data_size = sizeof(data), + .offsets_size = sizeof(offsets), + .data.ptr = { + (binder_uintptr_t)data, + (binder_uintptr_t)offsets + } + }, + .btd.buffers_size = sizeof(fdarray) + }; + + struct { + int32_t reply_noop; + } __attribute__((packed)) br; + + ret = do_binder_write_read(binder_fd, &bc, sizeof(bc), &br, sizeof(br)); + if (ret >= sizeof(br) && expect_binder_reply(br.reply_noop, BR_NOOP)) { + return -1; + } else if (ret < sizeof(br)) { + fprintf(stderr, "Not enough bytes in binder reply %d\n", ret); + return -1; + } + return 0; +} + +struct binder_transaction_data *binder_wait_for_transaction(int binder_fd, + uint32_t *readbuf, + size_t readsize) +{ + static const int MAX_EVENTS = 1, EPOLL_WAIT_TIME_MS = 3 * 1000; + struct binder_reply { + int32_t reply0; + int32_t reply1; + struct binder_transaction_data btd; + } *br; + struct binder_transaction_data *ret = NULL; + struct epoll_event events[MAX_EVENTS]; + int epoll_fd, num_events, readcount; + uint32_t bc[] = { BC_ENTER_LOOPER }; + + do_binder_write_read(binder_fd, &bc, sizeof(bc), NULL, 0); + + epoll_fd = epoll_create1(EPOLL_CLOEXEC); + if (epoll_fd == -1) { + perror("epoll_create"); + return NULL; + } + + events[0].events = EPOLLIN; + if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, binder_fd, &events[0])) { + perror("epoll_ctl add"); + goto err_close; + } + + num_events = epoll_wait(epoll_fd, events, MAX_EVENTS, EPOLL_WAIT_TIME_MS); + if (num_events < 0) { + perror("epoll_wait"); + goto err_ctl; + } else if (num_events == 0) { + fprintf(stderr, "No events\n"); + goto err_ctl; + } + + readcount = do_binder_write_read(binder_fd, NULL, 0, readbuf, readsize); + fprintf(stderr, "Read %d bytes from binder\n", readcount); + + if (readcount < (int)sizeof(struct binder_reply)) { + fprintf(stderr, "read_consumed not large enough\n"); + goto err_ctl; + } + + br = (struct binder_reply *)readbuf; + if (expect_binder_reply(br->reply0, BR_NOOP)) + goto err_ctl; + + if (br->reply1 == BR_TRANSACTION) { + if (br->btd.code == BINDER_CODE) + ret = &br->btd; + else + fprintf(stderr, "Received transaction with unexpected code: %u\n", + br->btd.code); + } else { + expect_binder_reply(br->reply1, BR_TRANSACTION_COMPLETE); + } + +err_ctl: + if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, binder_fd, NULL)) + perror("epoll_ctl del"); +err_close: + close(epoll_fd); + return ret; +} + +static int child_request_dmabuf_transfer(const char *cgroup, void *arg) +{ + UNUSED(cgroup); + int ret = -1; + uint32_t readbuf[32]; + struct binderfs_ctx bfs_ctx = *(struct binderfs_ctx *)arg; + struct binder_ctx b_ctx; + + fprintf(stderr, "Child PID: %d\n", getpid()); + + b_ctx = open_binder(&bfs_ctx); + if (b_ctx.fd < 0) { + fprintf(stderr, "Child unable to open binder\n"); + return -1; + } + + if (binder_request_dmabuf(b_ctx.fd)) + goto err; + + /* The child must stay alive until the binder reply is received */ + if (binder_wait_for_transaction(b_ctx.fd, readbuf, sizeof(readbuf)) == NULL) + ret = 0; + + /* + * We don't close the received dmabuf here so that the parent can + * inspect the cgroup gpu memory charges to verify the charge transfer + * completed successfully. + */ +err: + close_binder(&b_ctx); + fprintf(stderr, "Child done\n"); + return ret; +} + +TEST(gpu_cgroup_dmabuf_transfer) +{ + static const char * const GPUMEM_FILENAME = "gpu.memory.current"; + static const size_t ONE_MiB = 1024 * 1024; + + int ret, dmabuf_fd; + uint32_t readbuf[32]; + long memsize; + pid_t child_pid; + struct binderfs_ctx bfs_ctx; + struct binder_ctx b_ctx; + struct cgroup_ctx cg_ctx; + struct binder_transaction_data *tr; + struct flat_binder_object *fbo; + struct binder_buffer_object *bbo; + + if (geteuid() != 0) + ksft_exit_skip("Need to be root to mount binderfs\n"); + + bfs_ctx = create_binderfs("testbinder"); + if (bfs_ctx.name == NULL) + ksft_exit_skip("The Android binderfs filesystem is not available\n"); + + cg_ctx = create_cgroups(_metadata); + if (cg_ctx.root == NULL) { + destroy_binderfs(&bfs_ctx); + ksft_exit_skip("cgroup v2 isn't mounted\n"); + } + + ASSERT_EQ(cg_enter_current(cg_ctx.source), 0) { + TH_LOG("Could not move parent to cgroup: %s", cg_ctx.source); + goto err_cg; + } + + dmabuf_fd = alloc_dmabuf_from_system_heap(_metadata, ONE_MiB); + ASSERT_GE(dmabuf_fd, 0) { + goto err_cg; + } + TH_LOG("Allocated dmabuf"); + + memsize = cg_read_key_long(cg_ctx.source, GPUMEM_FILENAME, "system"); + ASSERT_EQ(memsize, ONE_MiB) { + TH_LOG("GPU memory used after allocation: %ld but it should be %lu", + memsize, (unsigned long)ONE_MiB); + goto err_dmabuf; + } + + b_ctx = open_binder(&bfs_ctx); + ASSERT_GE(b_ctx.fd, 0) { + TH_LOG("Parent unable to open binder"); + goto err_dmabuf; + } + TH_LOG("Opened binder at %s/%s", bfs_ctx.mountpoint, bfs_ctx.name); + + ASSERT_EQ(become_binder_context_manager(b_ctx.fd), 0) { + TH_LOG("Cannot become context manager: %s", strerror(errno)); + goto err_binder; + } + + child_pid = cg_run_nowait(cg_ctx.dest, child_request_dmabuf_transfer, &bfs_ctx); + ASSERT_GT(child_pid, 0) { + TH_LOG("Error forking: %s", strerror(errno)); + goto err_binder; + } + + tr = binder_wait_for_transaction(b_ctx.fd, readbuf, sizeof(readbuf)); + ASSERT_NE(tr, NULL) { + TH_LOG("Error receiving transaction request from child"); + goto err_child; + } + fbo = (struct flat_binder_object *)tr->data.ptr.buffer; + ASSERT_EQ(fbo->hdr.type, BINDER_TYPE_PTR) { + TH_LOG("Did not receive a buffer object from child"); + goto err_child; + } + bbo = (struct binder_buffer_object *)fbo; + ASSERT_EQ(bbo->length, 0) { + TH_LOG("Did not receive an empty buffer object from child"); + goto err_child; + } + + TH_LOG("Received transaction from child"); + send_dmabuf_reply(b_ctx.fd, tr, dmabuf_fd); + + ASSERT_EQ(cg_read_key_long(cg_ctx.dest, GPUMEM_FILENAME, "system"), ONE_MiB) { + TH_LOG("Destination cgroup does not have system charge!"); + goto err_child; + } + ASSERT_EQ(cg_read_key_long(cg_ctx.source, GPUMEM_FILENAME, "system"), 0) { + TH_LOG("Source cgroup still has system charge!"); + goto err_child; + } + TH_LOG("Charge transfer succeeded!"); + +err_child: + waitpid(child_pid, &ret, 0); + if (WIFEXITED(ret)) + TH_LOG("Child %d terminated normally with %d", child_pid, WEXITSTATUS(ret)); + else if (WIFSIGNALED(ret)) + TH_LOG("Child %d terminated with signal %d\n", child_pid, WTERMSIG(ret)); +err_binder: + close_binder(&b_ctx); +err_dmabuf: + close(dmabuf_fd); +err_cg: + destroy_cgroups(_metadata, &cg_ctx); + destroy_binderfs(&bfs_ctx); +} + +TEST_HARNESS_MAIN