Examples of Per-CPU Variables in Kernel source

2013-02-24 Thread Shraddha Kamat
I was reading about Per-CPU Variables from UTLK. Where are such variables used in the kernel source code - example. -- Shraddha ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org

Re: Examples of Per-CPU Variables in Kernel source

2013-02-24 Thread Shraddha Kamat
On Sun, 2013-02-24 at 14:07 +0530, Shraddha Kamat wrote: I was reading about Per-CPU Variables from UTLK. Where are such variables used in the kernel source code - example. -- Shraddha got a very nice article on Per-CPU variable here - http://www.makelinux.net/ldd3/chp-8-sect-5 that

Re: relocatable modules' symbols

2013-02-24 Thread Mulyadi Santosa
On Sat, Feb 23, 2013 at 6:45 AM, horseriver horseriv...@gmail.com wrote: hi: I have built vmlinux at the top dir of kernel source ,then I use objdump to look into its section information.I find the statup_32 which is the start routine of kernel , locats at 0xc010. I know the

atomic operations

2013-02-24 Thread Shraddha Kamat
what is the relation between atomic operations and memory alignment ? I read from UTLK that an unaligned memory access is not atomic please explain me , I am not able to get the relationship between memory alignment and atomicity of the operation.

Re: atomic operations

2013-02-24 Thread richard -rw- weinberger
On Sun, Feb 24, 2013 at 10:42 AM, Shraddha Kamat sh200...@gmail.com wrote: what is the relation between atomic operations and memory alignment ? I read from UTLK that an unaligned memory access is not atomic please explain me , I am not able to get the relationship between memory alignment

Re: relocatable modules' symbols

2013-02-24 Thread horseriver
On Sun, Feb 24, 2013 at 04:00:37PM +0700, Mulyadi Santosa wrote: On Sat, Feb 23, 2013 at 6:45 AM, horseriver horseriv...@gmail.com wrote: hi: I have built vmlinux at the top dir of kernel source ,then I use objdump to look into its section information.I find the statup_32 which is

Re: how to receive msgs in a channel?

2013-02-24 Thread horseriver
On Sun, Feb 24, 2013 at 11:47:50AM +, Mark Cunningham wrote: Just type and press enter. By default it goes to the room not one person. I do as you say. after I type enter , it said: Cannot send to channel I am join as a guest .does this matter? Mark On Sun, Feb 24, 2013 at

Re: atomic operations

2013-02-24 Thread Peter Teoh
in simple terms, any operation, in terms assembly instructions, which can be executed in ONE instruction, is atomic, because, just like an atom, it cannot be broken up into parts. any instructions that is longer than one, for eg, TWO instruction, is NOT atomic, because in BETWEEN the first and

Re: atomic operations

2013-02-24 Thread Valdis . Kletnieks
On Sun, 24 Feb 2013 11:50:14 +0100, richard -rw- weinberger said: On Sun, Feb 24, 2013 at 10:42 AM, Shraddha Kamat sh200...@gmail.com wrote: what is the relation between atomic operations and memory alignment ? I read from UTLK that an unaligned memory access is not atomic please

valid address space ?

2013-02-24 Thread Abu Rasheda
I am trying to dump some kernel data structure (walk e.g. task or file data structure on x86_64 arch). Sometime accessing through a pointer, pointer may not be NULL, but pointing to invalid address due to garbage value. What I am looking for is range of address which are valid for kernel data

Re: valid address space ?

2013-02-24 Thread Abu Rasheda
On Sunday, February 24, 2013, Abu Rasheda wrote: I am trying to dump some kernel data structure (walk e.g. task or file data structure on x86_64 arch). Sometime accessing through a pointer, pointer may not be NULL, but pointing to invalid address due to garbage value. What I am looking for

barrier()

2013-02-24 Thread Shraddha Kamat
#define barrier() asm volatile( ::: memory) What exactly volatile( ::: memory) doing here ? I was referring to gnu as (ver 2.14) manual but could not get much clue about this assembly construct - any pointers ? ___ Kernelnewbies mailing list

Re: test jiffies on ARM SMP board

2013-02-24 Thread bill4carson
On 2013年02月21日 00:39, buyitian wrote: i am confused about my test. in one device driver, i put below code: printk(start to test test jiffies\n); local_irq_save(flags); jf1 = jiffies; // read jiffies first time // hold cpu for about 2 seconds(do some calculation)

Re: test jiffies on ARM SMP board

2013-02-24 Thread bill4carson
On 2013年02月21日 01:30, Russell King - ARM Linux wrote: On Wed, Feb 20, 2013 at 10:54:41PM +0530, anish kumar wrote: On Thu, 2013-02-21 at 00:39 +0800, buyitian wrote: i am confused about my test. in one device driver, i put below code: printk(start to test test jiffies\n);

Re: atomic operations

2013-02-24 Thread Kumar amit mehta
On Sun, Feb 24, 2013 at 08:53:20PM +0800, Peter Teoh wrote: Another good article on atomicty and data sizes: http://www.ibm.com/developerworks/library/pa-atom/ On Sun, Feb 24, 2013 at 8:50 PM, Peter Teoh htmldevelo...@gmail.com wrote: in simple terms, any operation, in terms assembly

Re: barrier()

2013-02-24 Thread Valdis . Kletnieks
On Mon, 25 Feb 2013 12:26:06 +0530, Shraddha Kamat said: #define barrier() asm volatile( ::: memory) What exactly volatile( ::: memory) doing here ? You probably should read Documentation/memory-barriers.txt in your kernel source tree, and let us know if you still have questions after that...