* ggml : add `alloc_buffer_n` to buffer type interface
Add alloc_buffer_n method to ggml_backend_buffer_type_i
interface, with a public API ggml_backend_buft_alloc_buffer_n.
- Default implementation in ggml-backend.cpp handles multi-buffer
splitting and tensor allocation via ggml_tallocr
- Meta buffer type provides custom implementation that creates
per-device sub-contexts and delegates to simple buffer types
- ggml_backend_alloc_ctx_tensors_from_buft now collects tensors
into a list and delegates to the new API
- Remove temporary ggml_backend_meta_alloc_ctx_tensors_from_buft
- Add NULL alloc_buffer_n to all existing buffer type
interfaces (cpu, metal, openvino, hexagon, webgpu, zdnn, virtgpu, repack)
Assisted-by: llama.cpp:local pi
* cont : fix `cur_buf_size` init after flushing a buffer
* ggml : add TODO tag for shared buffer split logic
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* tests : add alloc_buffer_n coverage
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* cont : fix compile warnings
* tests : add descriptions for alloc_buffer_n tests
Assisted-by: pi:llama.cpp/Qwen3.8-27B
* ggml : address review comments on alloc_buffer_n
- restore GGML_LOG_ERROR on buffer alloc / tensor init failure in the
default impl (name the failing tensor)
- check the malloc result and drop the _impl indirection in
ggml_backend_alloc_ctx_tensors_from_buft
- remove comments that restate the code
- fix the TAG_ALLOC_SHARED_BUFFER_SPLIT typo
Assisted-by: pi:llama.cpp/Qwen3.8-27B
* ggml : add get_alloc_size_n to buffer type interface
- Add ggml_backend_buft_get_alloc_size_n public API
- Add optional get_alloc_size_n callback to ggml_backend_buffer_type_i
- Share tensor->buffer planning between alloc_buffer_n default and get_alloc_size_n default
- Replace unchecked realloc with std::vector in alloc_buffer_n default
- Make ggml_backend_alloc_ctx_tensors_from_buft_size use the new API
- Add test-alloc coverage for get_alloc_size_n
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* cont : report malloc failure
Georgi Gerganov
631109b34d