hi, interrupt comes to do any work its not at all concerned with current process executing,it might be the case that interrupt in interrupting other low priority interrupt,so current pointer is not valid here, in case of timer handler its work is to see that timeslice of current process expired or exhausted if it is then invoke the scheduler to schedule next one so it invokes with this specific task in mind, I think in LDD author meant that one cant do any work in interrupt concerning some specific process in mind beleiving some process always running if interrupt comes or anything like that. correct me if i'm wrong Prasanna --- Xia Nai <naixia@hotmail.com> wrote: > hi,all > In LDD2 Chapter6 "Flow of Time", it says "When > running in interrupt mode" code > is subject to a number of constraints, one of which > is "The current pointer > is not valid in interrupt mode, and cannot be used". > > But in the timer interrupt handler > do_timer()-->update_process_times(), the > "current" is explicitly referenced. > > Anyone explains this ? > > -- > Kernelnewbies: Help each other learn about the Linux > kernel. > Archive: > http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > __________________________________ Do you Yahoo!? Yahoo! Mail - Helps protect you from nasty viruses. http://promotions.yahoo.com/new_mail -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
