On 1/28/06, Ashok Sharma <aks6d@xxxxxxxxxxx> wrote: > > User preemption can occur when (i) returning to user > space from a system call (ii) when returning to user > space from an interrupt handler. > > My doubt is that one of these conditions may occur > Only after the time slice of a process is over. Worse > still can a user be executing without making a system > call or interrupt occurring. A process can run without making any sytem call to kernel, a programme running in infinite loop no instruction loop is one example, but interrupts can not be disabled by application programme in protected mode. Its the kernel mode only which can disable or enable the interrupts, so in any case interrupts will occur and more specifically timeer interrupt will occur after regular time intervals and while returning from these interupts the check is done for schedule as you mentioned. -Gaurav In this case user will > not preempt even long after the time slice is over as > preemption depends on conditions (i) and (ii) given > above. Or am I missing a point. Please explain. > > Best > Ashok > > > > ___________________________________________________________ > Win a BlackBerry device from O2 with Yahoo!. Enter now. http://www.yahoo.co.uk/blackberry > > -- > Kernelnewbies: Help each other learn about the Linux kernel. > Archive: http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
