public/fidl/fuchsia.memory/monitor.fidl

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
library fuchsia.memory;

// Interface used to register for memory notifications.
[Discoverable]
interface Monitor {
  1: Watch(Watcher watcher);
};

struct Stats {
  // The total amount of physical memory available to the system.
  uint64 total_bytes;

  // The amount of unallocated memory.
  uint64 free_bytes;

  // The amount of memory reserved by and mapped into the kernel for reasons
  // not covered by other fields in this struct. Typically for readonly data
  // like the ram disk and kernel image, and for early-boot dynamic memory.
  uint64 wired_bytes;

  // The amount of memory allocated to the kernel heap.
  uint64 total_heap_bytes;

  // The portion of |total_heap_bytes| that is not in use.
  uint64 free_heap_bytes;

  // The amount of memory committed to VMOs, both kernel and user.
  // A superset of all userspace memory.
  // Does not include certain VMOs that fall under |wired_bytes|.
  uint64 vmo_bytes;

  // The amount of memory used for architecture-specific MMU metadata
  // like page tables.
  uint64 mmu_overhead_bytes;

  // The amount of memory in use by IPC.
  uint64 ipc_bytes;

  // Non-free memory that isn't accounted for in any other field.
  uint64 other_bytes;
};

// A watcher for memory changes
interface Watcher {
  1: OnChange(Stats stats);
};