[PATCH] drm/amdkfd: Add available memory ioctl
David Yat Sin
david.yatsin at amd.com
Wed Jun 1 20:53:19 UTC 2022
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>
---
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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