> The nested interrupt call, do_IRQ(), may still try to call do_softirq() but > that it will return immediately as it discovers another instance of do_softirq() > is running. No further nesting occurs as a result. How is this detected ? Is this the check of "softirq_pending(cpu)" in the do_softirq() ? Can we have a case as shown below : 1. Interrupt 1 is generated : Jump to general exception handler (0x8000:0180) 2. Save the current context 3. Interrupt 1 is processed which schedules tasklet1 for execution. softirq_pending(cpu) = TASKLET_SOFTIRQ 4. Interrupts are reenabled. 5. do_softirq : Tasklet1 is executing & softirq_pending(cpu) = 0. 6. -------> Interrupt 2 is generated : Jump to general exception handler (0x8000:0180) 6a) Save the current context 6b) Interrupt2 is processed which schedules tasklet2 for execution. softirq_pending(cpu) = TASKLET_SOFTIRQ 6c) Interrupts are reenabled. 6d) do_softirq : Tasklet2 is executing & softirq_pending(cpu) = 0. 6e) ----> Interrupt3 is generated .... and so on. . . . 6f) Context is restored. Return from exception. . . . 7. Context is restored. Return from exception. Thanks. - Pankaj
