Try this command: dmesg | grep Memory For me the output is: [ 0.000000] Memory: 2007408k/2051636k available (4678k kernel code, 42932k reserved, 2124k data, 668k init, 1142332k highmem) Look here for more details: https://bbs.archlinux.org/viewtopic.php?id=14412 ~ Adheer From: geraint0923@gmail.com Date: Fri, 11 Nov 2011 13:28:53 +0800 Subject: Re: About kernel memory limit To: geek@uniserve.com CC: dhylands@gmail.com; kernelnewbies@kernelnewbies.org Thanks. But I think that command 'free' just tell the memory used in kernel space and user space.It is still unknown to us that how much memory is used by kernel. On Fri, Nov 11, 2011 at 1:15 PM, Dave Stevens <geek@uniserve.com> wrote: Quoting Geraint Yang <geraint0923@gmail.com>: Hi Dave, Thank you for your help ! Does it mean that I could use all of the memory my computer has? But one of my classmates told me that kernel could only use 1G from a 4G memory.computer...Is there anything I have misunderstood ? I'm sitting in front of a Ubuntu box with 8G installed, uname -a shows: Linux roger-System-Product-Name 3.0.0-12-generic #20-Ubuntu SMP Fri Oct 7 14:56:25 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux so kernel 3 and free: shows total used free shared buffers cached Mem: 8192500 2907656 5284844 0 162060 1915540 -/+ buffers/cache: 830056 7362444 Swap: 7812092 0 7812092 so 2.9G of 8 in use Dave On Fri, Nov 11, 2011 at 4:58 AM, Dave Hylands <dhylands@gmail.com> wrote: Hi, On Thu, Nov 10, 2011 at 6:23 AM, Geraint Yang <geraint0923@gmail.com> wrote:
Hi there,
I am a newbie to Linux kernel programming. I am going to make a module
which will cost much memory in kernel, I just want to know how much
memory I can get by calling memory allocate API in kernel.
All of it.
From kernel space, you can completely exhaust memory to the point of
making your system unusable.
From kernel space you have vmalloc memory and kmalloc memory (plus a
couple other memory spaces). Depending on how things are configured, it's possible to exhaust vmalloc memory even though there is memory available to be kmalloc'd. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com -- Geraint Yang Tsinghua University Department of Computer Science and Technology -- It is told that such are the aerodynamics and wing loading of the bumblebee that, in principle, it cannot fly...if all this be true...life among bumblebees must bear a remarkable resemblance to life in the United States. -- John Kenneth Galbraith, in American Capitalism: The Concept of Countervailing Power -- Geraint Yang Tsinghua University Department of Computer Science and Technology _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies