Hi, all:
I allocated some physical pages using __get_free_pages() api and mapped
them into user-space with mmap() in my driver,
but It seems not be shared in multi process.
Following is content of /proc/157/maps file. The vma range of 40244000-40444000
mapped to /dev/mux_dev, notice the rw-p column.
/proc/157 $ cat maps
00008000-000c6000 r-xp 00000000 00:0b 262686 /mnt/nfs/mux_test
000ce000-00882000 rw-p 000be000 00:0b 262686 /mnt/nfs/mux_test
40000000-40015000 r-xp 00000000 00:01 142 /lib/ld-2.3.5.so
40015000-40017000 rw-p 40015000 00:00 0
4001c000-4001d000 r--p 00014000 00:01 142 /lib/ld-2.3.5.so
4001d000-4001e000 rw-p 00015000 00:01 142 /lib/ld-2.3.5.so
40020000-4002f000 r-xp 00000000 00:01 154 /lib/libpthread-0.10.so
4002f000-40036000 ---p 0000f000 00:01 154 /lib/libpthread-0.10.so
40036000-40037000 r--p 0000e000 00:01 154 /lib/libpthread-0.10.so
40037000-40038000 rw-p 0000f000 00:01 154 /lib/libpthread-0.10.so
40038000-4007a000 rw-p 40038000 00:00 0
4007c000-40123000 r-xp 00000000 00:01 156 /lib/libm-2.3.5.so
40123000-4012a000 ---p 000a7000 00:01 156 /lib/libm-2.3.5.so
4012a000-4012b000 r--p 000a6000 00:01 156 /lib/libm-2.3.5.so
4012b000-4012c000 rw-p 000a7000 00:01 156 /lib/libm-2.3.5.so
4012c000-40236000 r-xp 00000000 00:01 157 /lib/libc-2.3.5.so
40236000-4023d000 ---p 0010a000 00:01 157 /lib/libc-2.3.5.so
4023d000-4023f000 r--p 00109000 00:01 157 /lib/libc-2.3.5.so
4023f000-40242000 rw-p 0010b000 00:01 157 /lib/libc-2.3.5.so
40242000-40244000 rw-p 40242000 00:00 0
40244000-40444000 rw-p 00000000 00:01 722 /dev/mux_dev
be9bf000-be9d4000 rwxp be9bf000 00:00 0 [stack]
