On Wed, Apr 13, 2011 at 2:54 PM, Pintu Agarwal <pintu_agarwal@xxxxxxxxx> wrote: > Dear All, > > I am trying to understand how memory fragmentation occurs in linux using many malloc calls. > I am trying to reproduce the page fragmentation problem in linux 2.6.29.x on a linux mobile(without Swap) using a small malloc(in loop) test program of BLOCK_SIZE (64*(4*K)). > And then monitoring the page changes in /proc/buddyinfo after each operation. > From the output I can see that the page values under buddyinfo keeps changing. But I am not able to relate these changes with my malloc BLOCK_SIZE. > I mean with my BLOCK_SIZE of (2^6 x 4K ==> 2^6 PAGES) the 2^6 th block under /proc/buddyinfo should change. But this is not the actual behaviour. > Whatever is the blocksize, the buddyinfo changes only for 2^0 or 2^1 or 2^2 or 2^3. > > I am trying to measure the level of fragmentation after each page allocation. > Can somebody explain me in detail, how actually /proc/buddyinfo changes after each allocation and deallocation. > What malloc() sees is virtual memory of the process, while buddyinfo shows physical memory pages. When you malloc() 64K memory, the kernel may not allocate a 64K physical memory at one time for you. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
