gpu: nvgpu: add ioctl for querying memory state

Add NVGPU_GPU_IOCTL_GET_MEMORY_STATE to read the amount of free
device-local video memory, if applicable.

Some reserved fields are added to support different types of queries in
the future (e.g. context-local free amount).

Bug 1787771
Bug 200233138

Change-Id: Id5ffd02ad4d6ed3a6dc196541938573c27b340ac
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/1223762
(cherry picked from commit 96221d96c7972c6387944603e974f7639d6dbe70)
Reviewed-on: http://git-master/r/1235980
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/include/uapi/linux/nvgpu.h b/include/uapi/linux/nvgpu.h
index 84732452..0bf88628 100644
--- a/include/uapi/linux/nvgpu.h
+++ b/include/uapi/linux/nvgpu.h
@@ -510,6 +510,18 @@ struct nvgpu_gpu_alloc_vidmem_args {
         };
 };
 
+struct nvgpu_gpu_get_memory_state_args {
+        /*
+         * Current free space for this device; may change even when any
+         * kernel-managed metadata (e.g., page tables or channels) is allocated
+         * or freed. For an idle gpu, an allocation of this size would succeed.
+         */
+        __u64 total_free_bytes;
+
+        /* For future use; must be set to 0. */
+        __u64 reserved[4];
+};
+
 #define NVGPU_GPU_IOCTL_ZCULL_GET_CTX_SIZE \
         _IOR(NVGPU_GPU_IOCTL_MAGIC, 1, struct nvgpu_gpu_zcull_get_ctx_size_args)
 #define NVGPU_GPU_IOCTL_ZCULL_GET_INFO \
@@ -568,8 +580,11 @@ struct nvgpu_gpu_alloc_vidmem_args {
 #define NVGPU_GPU_IOCTL_ALLOC_VIDMEM \
         _IOWR(NVGPU_GPU_IOCTL_MAGIC, 27, \
                         struct nvgpu_gpu_alloc_vidmem_args)
+#define NVGPU_GPU_IOCTL_GET_MEMORY_STATE \
+        _IOWR(NVGPU_GPU_IOCTL_MAGIC, 33, \
+                        struct nvgpu_gpu_get_memory_state_args)
 #define NVGPU_GPU_IOCTL_LAST            \
-        _IOC_NR(NVGPU_GPU_IOCTL_ALLOC_VIDMEM)
+        _IOC_NR(NVGPU_GPU_IOCTL_GET_MEMORY_STATE)
 #define NVGPU_GPU_IOCTL_MAX_ARG_SIZE    \
         sizeof(struct nvgpu_gpu_get_cpu_time_correlation_info_args)