Hi... I am not ARM guy, but I'll see what I can share here..... hold your breath :) On Tue, May 31, 2011 at 12:54, sandeep kumar <coolsandyforyou@gmail.com> wrote:
Hi all, The following link gives the memory map for the arm architecture. http://www.arm.linux.org.uk/developer/memory.txt
I have the following doubts.. 1) Any chipset(based on arm) manufacturer(qualcom,samsung..) should follow the same memory map. Is it hardly constrained or can be changed? Where are this constraints are implemented in the kernel source tree?
you mean, device memory map? well AFAIK that is dictated by BIOS....kernel simply just follow along...
2) while i was student, i read in OS concepts that, "Virtual memory gives an illusion to a process, that it has always a larger continuous address space (even more than RAM) available to it."
that's true... but you need to count another limitation: addressable or not by the MMU or at least processor itself? let's say you have 16 GiB of virtual memory, composed of 4 GiB of RAM + 12 GiB swap. Theoritically, a single process should be able to use them all, but assuming we have no PAE enabled, an 32 bit system could only address up to 4 GiB
So i thought i could allocate howmuch ever memory i want.
Also think about fragmentation...
But seeing the above link,i observed there is some limitation in the address space created by the vmalloc(). So i m now thinking that vmalloc has some limit.
Yup..... maybe my old article could shed a light further for you: http://linuxdevcenter.com/pub/a/linux/2006/11/30/linux-out-of-memory.html -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com