Segment 3 is for memory for mapped files, mmap'd memory.

段 3 预留给内存映射文件，即 mmap。

youdao

High performance (SendFile API support and memory-mapped files).

高性能(支持SendFile API和内存映射文件)。

youdao

To help improve startup time, the JVM now works with memory-mapped files.

为了帮助改善启动时间，JVM现在和内存映射文件一起工作。

youdao

Because I'm also an inveterate saver of computer files, I still have my carefully mapped-out itinerary for the trip, and thus can tell you with certainty that this story took place on Nov. 12, 2001.

WSJ: Teddy Wayne on Locking Himself Up in Vienna |Traveler's Tale