Hi, I have some basic questions. Answering just yes or no should suffice for me. If we say there are 3 levels of execution context: 1) Process context 2) Bottom-Half context 3) Irq context Is it correct to say that; 1) An in-interrupt context cannot sleep but it can be preempted if the irqs are enabled. (Examples: inside a non-SA_INTERRUPT interrupt handler or a tasklet) Spinlocks: 2) No matter what context you are in, by acquiring a spinlock, preemption is *always* disabled, to cover for the *always possible* case of another process scheduling and deadlocking on the lock. 3) No matter what context you're in, *if, and only if* your spinlock is shared with BH and/or Irq contexts, you disable them on the current CPU, for they may interrupt yours, and deadlock on your spinlock. 4) Disabling of contexts for a spinlock is to protect against deadlocks from the current CPU, whereas the spinlock itself is to protect against races across CPUs. Does this also imply, the runqueue of a CPU would never be balanced when a context on that CPU holds a spinlock? Thanks, Bahadir -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
