Hi Niroj.... Please see inlined answer below... On Mon, Mar 18, 2013 at 5:28 PM, Niroj Pokhrel <nirojpokhrel@xxxxxxxxx> wrote: > Hi all, > As I have read, whenever we execute a program, the memory is allocated in > different sections viz stack, text and data segment. Yup, that is correct > But, since we have used > loader and linker the three allocations will happen for them too. Correct again. Linker and loader will be the part of process address space. > But when I ran a program and did pmap pid, I saw several other fields which > I have no idea of. What is the [anon] and what is it doing here ? Anon is short of anonymous. It is a region of memory created by function e.g malloc() or mmap() >Why the > memory is being implemented for it and there are so many of them ? Drawing from above explanation, we can easily conclude somewhere in the program, it does malloc() or mmap(). > And also the stack ( 3rd last element), is it the process stack?? Yes, it's process' stack >Can > somebody please explain. > Thanking you all in advance. > > 5448: ./a.out > 0000000000400000 4K r-x-- /home/n.pokhrel/Personal/mywork/a.out > 0000000000600000 4K r---- /home/n.pokhrel/Personal/mywork/a.out > 0000000000601000 4K rw--- /home/n.pokhrel/Personal/mywork/a.out > 00007f57f5e18000 1512K r-x-- /lib/libc-2.11.1.so > 00007f57f5f92000 2044K ----- /lib/libc-2.11.1.so > 00007f57f6191000 16K r---- /lib/libc-2.11.1.so > 00007f57f6195000 4K rw--- /lib/libc-2.11.1.so > 00007f57f6196000 20K rw--- [ anon ] > 00007f57f619b000 128K r-x-- /lib/ld-2.11.1.so > 00007f57f6396000 12K rw--- [ anon ] > 00007f57f63b8000 8K rw--- [ anon ] > 00007f57f63ba000 4K r---- /lib/ld-2.11.1.so > 00007f57f63bb000 4K rw--- /lib/ld-2.11.1.so > 00007f57f63bc000 4K rw--- [ anon ] > 00007fffa2f37000 84K rw--- [ stack ] > 00007fffa2fa0000 4K r-x-- [ anon ] > ffffffffff600000 4K r-x-- [ anon ] ok, one of the region above, I think it's VDSO (virtual dynamic shared object). It's a region that handle system call. When a process does system call, it jumps to VDSO, and it is the VDSO that does the actuall syscall -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
