> then the question is when we should use which way? thanks! set_bit() and friends are "smp safe", that is, if multiple cpus access the same memory location (doesn't ahve to be the same bit) at the same time, it's safe. bitfields do not provide that safety, if cpu 0 is writing bit 0, and cpu 1 is writing bit 4 of a memory location, a really big mess will happen. The flipside of that is that the "smp safe" comes with a price; it needs atomic operations on the cpu level, and those are really expensive. So maybe a rule of thumb: If you can guarantee that there will be no parallel accesses (due to spinlocks or due to how your code works), use bitfields. If you need your code to be SMP safe on itself, use set_bit() and co. If you fall in either, think again, because you do you just don't know it yet ;) -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
