Sean Keely
df55cb0450
Prior solution used a single global lock to protect the memory tracking structures. This change protects the memory tracking structure with a shared mutex (rw lock) in shared (r) mode for memory allocations and frees so that long duration processes, calling to kfd, can be done in parallel. Operations which must modify the memory map take the mutex in exclusive mode (w) and must not call to the thunk while holding the mutex. The fragment allocator now requires separate protection and is protected with a mutex at the device level. Protecting at the device level, rather than pool, allows retention of the current recursive design and allows calling Trim from withing Allocate. This could be made finer (pool level locks) but would require backing out of Allocate entirely to call Trim. Trim and any retried Allocation must be done in isolation (per device) or we may report OOM when memory is actually available in some pool's fragment cache. So some device level serialization is required in at least some paths. Change-Id: I7c1e94d6965ffcc602b12fefdd3a6e97b84b5e00