This directory contains symbolic links which represent memory mapped files the process is maintaining.
Example output:
dr-x------ 2 akash akash 0 Mar 27 21:32 ./
dr-xr-xr-x 9 akash akash 0 Mar 27 21:32 ../
lr-------- 1 akash akash 64 Mar 27 21:32 564277720000-56427773f000 -> /bin/ls*
lr-------- 1 akash akash 64 Mar 27 21:32 56427793e000-564277940000 -> /bin/ls*
lr-------- 1 akash akash 64 Mar 27 21:32 564277940000-564277941000 -> /bin/ls*
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1a833000-7fcb1a83e000 -> /lib/x86_64-linux-gnu/libnss_files-2.27.so
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1a83e000-7fcb1aa3d000 -> /lib/x86_64-linux-gnu/libnss_files-2.27.so
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1aa3d000-7fcb1aa3e000 -> /lib/x86_64-linux-gnu/libnss_files-2.27.so
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1aa3e000-7fcb1aa3f000 -> /lib/x86_64-linux-gnu/libnss_files-2.27.so
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1aa45000-7fcb1aa5c000 -> /lib/x86_64-linux-gnu/libnsl-2.27.so
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1aa5c000-7fcb1ac5b000 -> /lib/x86_64-linux-gnu/libnsl-2.27.so
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1ac5b000-7fcb1ac5c000 -> /lib/x86_64-linux-gnu/libnsl-2.27.so
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1ac5c000-7fcb1ac5d000 -> /lib/x86_64-linux-gnu/libnsl-2.27.so
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1ac5f000-7fcb1ac6a000 -> /lib/x86_64-linux-gnu/libnss_nis-2.27.so
lr-------- 1 akash akash 64 Mar 27 21:32 7fcb1ac6a000-7fcb1ae69000 -> /lib/x86_64-linux-gnu/libnss_nis-2.27.so
The name of a link represents the virtual memory bounds of a mapping, i.e.
vm_area_struct::vm_start-vm_area_struct::vm_end.
The main purpose of the map_files is to retrieve a set of memory mapped files in a fast way instead of parsing /proc/maps or /proc/smaps, both of which contain many more records. At the same time one can open(2) mappings from the listings of two processes and comparing their inode numbers to figure out which anonymous memory areas are actually shared.