使用mmap读取非惰性文件？

Question

When you use mmap to read from a file, it performs lazy file read, that is it brings only the data that you use from the hard disk to RAM. Now, is there any method with which we can force the whole file to be read into the RAM at once?

Answer 1

From the mmap(2) man page:

MAP_POPULATE (since Linux 2.5.46)

Populate (prefault) page tables for a mapping. For a file mapping, this causes read-ahead on the file. Later accesses to the mapping will not be blocked by page faults. MAP_POPULATE is supported for private mappings only since Linux 2.6.23.