Function Init

pkg/sentry/usage/memory.go:250–280

Init initializes global 'MemoryAccounting'.

()

// Init initializes global 'MemoryAccounting'.
func Init() error {
	initOnce.Do(func() {
		initErr = func() error {
			const name = "memory-usage"
			fd, err := memutil.CreateMemFD(name, 0)
			if err != nil {
				return fmt.Errorf("error creating usage file: %v", err)
			}
			file := os.NewFile(uintptr(fd), name)
			if err := file.Truncate(int64(RTMemoryStatsSize)); err != nil {
				return fmt.Errorf("error truncating usage file: %v", err)
			}
			// Note: We rely on the returned page being initially zeroed. This will
			// always be the case for a newly mapped page from /dev/shm. If we obtain
			// the shared memory through some other means in the future, we may have to
			// explicitly zero the page.
			mmap, err := memutil.MapFile(0, RTMemoryStatsSize, unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED, file.Fd(), 0)
			if err != nil {
				return fmt.Errorf("error mapping usage file: %v", err)
			}

			MemoryAccounting = &MemoryLocked{
				File:              file,
				RTMemoryStats:     RTMemoryStatsPointer(mmap),
				MemCgIDToMemStats: make(map[uint32]*memoryStats),
			}
			return nil
		}()
	})
	return initErr
}

// MemoryAccounting is the global memory stats.
//