> > >From what you all discuss, I can say: kernel memory is devided into 2 > > part, and the upper part are shared between processes. The below part > > (the kernel stack, or 8K traditionally) is specifict for each process. > > > > Is that right? > > No, it's not. There is just one kernel memory. In it each process has > it's own task_struct + kernel stack (by default 8K). There is no special > address mapping for these, nor are they allocated from a special area. > > When a context of some process is entered, esp is pointed to the top of > it's stack. That's exactly all it takes to exchange stacks. OK, lets say there are 20 processes running in the system. Then the kernel must allocate 20 * 8K = 160K just for the stacks of these processes. All of these 160K always occupy the kernel (kernel memory is never swapped out). When a process actives, ESP would switch to point to the corresponding stack (of that process). The remainding memory of kernel therefore is equally accessible to all the processes. Is that correct ? Thank you, AQ -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
