| // include/strata/platform/memory.hpp - plan v0.3 P0.1/P1: keep a large host region resident. | |
| // | |
| // `cudaHostRegister` refuses the 31.6 GiB expert arena on Windows, and an unlocked arena is trimmed under memory | |
| // pressure (the CPU pool then swung 2x between runs). With the n-gram table out of RAM there is headroom to lock | |
| // it instead: raise the process's minimum working set by the region's size, then VirtualLock it (Windows needs | |
| // only SeIncreaseWorkingSetPrivilege, which ordinary accounts hold). Linux: mlock. | |
| namespace strata::platform { | |
| struct LockResult { | |
| bool ok = false; | |
| uint64_t locked_bytes = 0; ///< may be less than requested; the rest stays pageable | |
| std::string note; ///< what was done or why it failed, for the startup print | |
| }; | |
| /// Lock [p, p + bytes) into physical memory. Partial success is reported, not hidden. | |
| LockResult lock_resident(void* p, uint64_t bytes); | |
| /// Undo lock_resident for the same region (best effort). | |
| void unlock_resident(void* p, uint64_t bytes); | |
| /// #243, Windows: the GPU's shared (non-local) memory budget and this process's use of it, from DXGI | |
| /// (IDXGIAdapter3::QueryVideoMemoryInfo, DXGI_MEMORY_SEGMENT_GROUP_NON_LOCAL) for the adapter whose LUID is the | |
| /// 8 bytes at `luid` (cudaDeviceProp::luid). Page-locked host memory the GPU maps is charged there. False (and | |
| /// `why` says so) when the query is not possible - always elsewhere than Windows. | |
| bool gpu_shared_memory_budget(const void* luid, uint64_t& budget, uint64_t& usage, std::string& why); | |
| /// The machine's physical RAM in bytes (0 when unknown). | |
| uint64_t total_physical_memory(); | |
| } // namespace strata::platform | |