// Package mmap implements a large block memory allocator using // anonymous memory maps. // +build !plan9,!windows,!js package mmap import ( "github.com/pkg/errors" "golang.org/x/sys/unix" ) // Alloc allocates size bytes and returns a slice containing them. If // the allocation fails it will return with an error. This is best // used for allocations which are a multiple of the PageSize. func Alloc(size int) ([]byte, error) { mem, err := unix.Mmap(-1, 0, size, unix.PROT_READ|unix.PROT_WRITE, unix.MAP_PRIVATE|unix.MAP_ANON) if err != nil { return nil, errors.Wrap(err, "mmap: failed to allocate memory for buffer") } return mem, nil } // Free frees buffers allocated by Alloc. Note it should be passed // the same slice (not a derived slice) that Alloc returned. If the // free fails it will return with an error. func Free(mem []byte) error { err := unix.Munmap(mem) if err != nil { return errors.Wrap(err, "mmap: failed to unmap memory") } return nil }