On Mon, 2004-03-22 at 00:45, Amith wrote: Hi, > "At any time each of the CPUs in a system can be: > > 1) not associated with any process, serving a hardware interrupt; > > 2) not associated with any process, serving a softirq, tasklet or bh; > > 3) running in kernel space, associated with a process; > > 4) running a process in user space. " > > I have some confusions here . > In (3) running in kernel space, associated with a process; - can this > state be understood as - the kernel is executing a system call() on > behalf of a process ? Yes, basically. The kernel is doing _something_ on behalf of a process. This is usually a system call, however it can be any sort of trap, e.g. a page fault, too. > i'am not clear about the last one (4) too . I understood it as the CPU > executing a statement like - > count = count + 1; > in a user program. Well, any code. Not just that statement. But all of the code that your user process executes from its binary image. Robert Love -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
