I would like to understand on linux scheduler context. I have read a lot in websites and i could find contradictory statement. There are so many mailing list also ,but with less info. I would really appreciate if anybody could spend some time answering my question. 1. Which context scheduler run ? ( process context or interrupt context ). 2. scheduler is the guy who picks up the next candidate to run. if it gets interrupted by hardirq, what will happen ? 3. if scheduler run in process context , how bottom half are scheduled ? 4. In smp, schedule() function may be called simultaneously. How it is handled ? 5. When a bottom half is interrupted by hard irq, how softirq kernel thread saves the state and restart it later ? ...what i mean is , an hardirq came and its isr executed. bottom half enabled and bottom half gets scheduled . Before bottom half is completed , next irq came and it enables bottom half , and the new bottom half is scheduled ....So here , what will happen to old bottom half , will it again run later ? Thanks, Ratheesh