On Tue, Oct 12, 2004 at 21:30:54 +0900, aq wrote: > > > >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). This is correct. > The remainding memory of kernel therefore is equally accessible to all > the processes. This is not. There is nothing like "remaining memory". **ALL* kernel memory is equally accessible to all the processes. There is noting special about the stacks and task-structs. They are normal 8K structures somewhere in kernel memory. > Is that correct ? ------------------------------------------------------------------------------- Jan 'Bulb' Hudec <bulb@xxxxxx>
Attachment:
signature.asc
Description: Digital signature
