[PATCH] drm/amdkfd: Add available memory ioctl
Alex Deucher
alexdeucher at gmail.com
Wed Jun 1 21:01:36 UTC 2022
On Wed, Jun 1, 2022 at 4:53 PM David Yat Sin <david.yatsin at amd.com> wrote:
>
> From: Daniel Phillips <Daniel.Phillips at amd.com>
>
> Add a new KFD ioctl to return the largest possible memory size that
> can be allocated as a buffer object using
> kfd_ioctl_alloc_memory_of_gpu. It attempts to use exactly the same
> accept/reject criteria as that function so that allocating a new
> buffer object of the size returned by this new ioctl is guaranteed to
> succeed, barring races with other allocating tasks.
>
> Signed-off-by: Daniel Phillips <Daniel.Phillips at amd.com>
> Signed-off-by: David Yat Sin <david.yatsin at amd.com>
Got a link to the new UMD code which uses this? Please include that
in the commit message.
Thanks,
Alex
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 1 +
> .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 37 +++++++++++++++++--
> drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 34 +++++++++++++++++
> include/uapi/linux/kfd_ioctl.h | 14 ++++++-
> 4 files changed, 80 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
> index f8b9f27adcf5..0b0ab1de76ca 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
> @@ -266,6 +266,7 @@ int amdgpu_amdkfd_gpuvm_acquire_process_vm(struct amdgpu_device *adev,
> void amdgpu_amdkfd_gpuvm_release_process_vm(struct amdgpu_device *adev,
> void *drm_priv);
> uint64_t amdgpu_amdkfd_gpuvm_get_process_page_dir(void *drm_priv);
> +size_t amdgpu_amdkfd_get_available_memory(struct amdgpu_device *adev);
> int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
> struct amdgpu_device *adev, uint64_t va, uint64_t size,
> void *drm_priv, struct kgd_mem **mem,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> index 34ba9e776521..105af82d41a4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> @@ -38,6 +38,12 @@
> */
> #define AMDGPU_USERPTR_RESTORE_DELAY_MS 1
>
> +/*
> + * Align VRAM allocations to 2MB to avoid fragmentation caused by 4K allocations in the tail 2MB
> + * BO chunk
> + */
> +#define VRAM_ALLOCATION_ALIGN (1 << 21)
> +
> /* Impose limit on how much memory KFD can use */
> static struct {
> uint64_t max_system_mem_limit;
> @@ -108,7 +114,7 @@ void amdgpu_amdkfd_reserve_system_mem(uint64_t size)
> * compromise that should work in most cases without reserving too
> * much memory for page tables unnecessarily (factor 16K, >> 14).
> */
> -#define ESTIMATE_PT_SIZE(mem_size) ((mem_size) >> 14)
> +#define ESTIMATE_PT_SIZE(mem_size) max(((mem_size) >> 14), AMDGPU_VM_RESERVED_VRAM)
>
> static size_t amdgpu_amdkfd_acc_size(uint64_t size)
> {
> @@ -148,7 +154,12 @@ static int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
> } else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_VRAM) {
> system_mem_needed = acc_size;
> ttm_mem_needed = acc_size;
> - vram_needed = size;
> +
> + /*
> + * Conservatively round up the allocation requirement to 2 MB to avoid fragmentation
> + * caused by 4K allocations in the tail 2M BO chunk
> + */
> + vram_needed = ALIGN(size, VRAM_ALLOCATION_ALIGN);
> } else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) {
> system_mem_needed = acc_size + size;
> ttm_mem_needed = acc_size;
> @@ -173,7 +184,9 @@ static int amdgpu_amdkfd_reserve_mem_limit(struct amdgpu_device *adev,
> (kfd_mem_limit.ttm_mem_used + ttm_mem_needed >
> kfd_mem_limit.max_ttm_mem_limit) ||
> (adev->kfd.vram_used + vram_needed >
> - adev->gmc.real_vram_size - reserved_for_pt)) {
> + adev->gmc.real_vram_size -
> + atomic64_read(&adev->vram_pin_size) -
> + reserved_for_pt)) {
> ret = -ENOMEM;
> goto release;
> }
> @@ -205,7 +218,7 @@ static void unreserve_mem_limit(struct amdgpu_device *adev,
> } else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_VRAM) {
> kfd_mem_limit.system_mem_used -= acc_size;
> kfd_mem_limit.ttm_mem_used -= acc_size;
> - adev->kfd.vram_used -= size;
> + adev->kfd.vram_used -= ALIGN(size, VRAM_ALLOCATION_ALIGN);
> } else if (alloc_flag & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) {
> kfd_mem_limit.system_mem_used -= (acc_size + size);
> kfd_mem_limit.ttm_mem_used -= acc_size;
> @@ -1492,6 +1505,22 @@ int amdgpu_amdkfd_criu_resume(void *p)
> return ret;
> }
>
> +size_t amdgpu_amdkfd_get_available_memory(struct amdgpu_device *adev)
> +{
> + uint64_t reserved_for_pt =
> + ESTIMATE_PT_SIZE(amdgpu_amdkfd_total_mem_size);
> + size_t available;
> +
> + spin_lock(&kfd_mem_limit.mem_limit_lock);
> + available = adev->gmc.real_vram_size
> + - adev->kfd.vram_used
> + - atomic64_read(&adev->vram_pin_size)
> + - reserved_for_pt;
> + spin_unlock(&kfd_mem_limit.mem_limit_lock);
> +
> + return ALIGN_DOWN(available, VRAM_ALLOCATION_ALIGN);
> +}
> +
> int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
> struct amdgpu_device *adev, uint64_t va, uint64_t size,
> void *drm_priv, struct kgd_mem **mem,
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> index 95fa7a9718bb..625e837f0119 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> @@ -65,6 +65,25 @@ static int kfd_char_dev_major = -1;
> static struct class *kfd_class;
> struct device *kfd_device;
>
> +static inline struct kfd_process_device *kfd_lock_pdd_by_id(struct kfd_process *p, __u32 gpu_id)
> +{
> + struct kfd_process_device *pdd;
> +
> + mutex_lock(&p->mutex);
> + pdd = kfd_process_device_data_by_id(p, gpu_id);
> +
> + if (pdd)
> + return pdd;
> +
> + mutex_unlock(&p->mutex);
> + return NULL;
> +}
> +
> +static inline void kfd_unlock_pdd(struct kfd_process_device *pdd)
> +{
> + mutex_unlock(&pdd->process->mutex);
> +}
> +
> int kfd_chardev_init(void)
> {
> int err = 0;
> @@ -958,6 +977,19 @@ bool kfd_dev_is_large_bar(struct kfd_dev *dev)
> return false;
> }
>
> +static int kfd_ioctl_get_available_memory(struct file *filep,
> + struct kfd_process *p, void *data)
> +{
> + struct kfd_ioctl_get_available_memory_args *args = data;
> + struct kfd_process_device *pdd = kfd_lock_pdd_by_id(p, args->gpu_id);
> +
> + if (!pdd)
> + return -EINVAL;
> + args->available = amdgpu_amdkfd_get_available_memory(pdd->dev->adev);
> + kfd_unlock_pdd(pdd);
> + return 0;
> +}
> +
> static int kfd_ioctl_alloc_memory_of_gpu(struct file *filep,
> struct kfd_process *p, void *data)
> {
> @@ -2642,6 +2674,8 @@ static const struct amdkfd_ioctl_desc amdkfd_ioctls[] = {
> AMDKFD_IOCTL_DEF(AMDKFD_IOC_CRIU_OP,
> kfd_ioctl_criu, KFD_IOC_FLAG_CHECKPOINT_RESTORE),
>
> + AMDKFD_IOCTL_DEF(AMDKFD_IOC_AVAILABLE_MEMORY,
> + kfd_ioctl_get_available_memory, 0),
> };
>
> #define AMDKFD_CORE_IOCTL_COUNT ARRAY_SIZE(amdkfd_ioctls)
> diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h
> index eb9ff85f8556..c648ed7c5ff1 100644
> --- a/include/uapi/linux/kfd_ioctl.h
> +++ b/include/uapi/linux/kfd_ioctl.h
> @@ -34,9 +34,10 @@
> * - 1.6 - Query clear flags in SVM get_attr API
> * - 1.7 - Checkpoint Restore (CRIU) API
> * - 1.8 - CRIU - Support for SDMA transfers with GTT BOs
> + * - 1.9 - Add available memory ioctl
> */
> #define KFD_IOCTL_MAJOR_VERSION 1
> -#define KFD_IOCTL_MINOR_VERSION 8
> +#define KFD_IOCTL_MINOR_VERSION 9
>
> struct kfd_ioctl_get_version_args {
> __u32 major_version; /* from KFD */
> @@ -100,6 +101,12 @@ struct kfd_ioctl_get_queue_wave_state_args {
> __u32 pad;
> };
>
> +struct kfd_ioctl_get_available_memory_args {
> + __u64 available; /* from KFD */
> + __u32 gpu_id; /* to KFD */
> + __u32 pad;
> +};
> +
> /* For kfd_ioctl_set_memory_policy_args.default_policy and alternate_policy */
> #define KFD_IOC_CACHE_POLICY_COHERENT 0
> #define KFD_IOC_CACHE_POLICY_NONCOHERENT 1
> @@ -824,7 +831,10 @@ struct kfd_ioctl_set_xnack_mode_args {
> #define AMDKFD_IOC_CRIU_OP \
> AMDKFD_IOWR(0x22, struct kfd_ioctl_criu_args)
>
> +#define AMDKFD_IOC_AVAILABLE_MEMORY \
> + AMDKFD_IOWR(0x23, struct kfd_ioctl_get_available_memory_args)
> +
> #define AMDKFD_COMMAND_START 0x01
> -#define AMDKFD_COMMAND_END 0x23
> +#define AMDKFD_COMMAND_END 0x24
>
> #endif
> --
> 2.30.2
>
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