Context switch will be made while returning to user mode. Ketan Sonawane, Rahul (Rahul) wrote: > Hi Ketan, > The kernel is not preemptive is kernel mode ..which means a context switch cannot happen if the process is executing > in the kernel mode. Say it is executing a system call and it is executing in kernel mode ..Now a timer interrupt occurs > and it gets executed in the current process context . The timer interrupt found decrements the process counter ..finds it to be zero and sets the reshed_flag = 1; > I want to know when will the context switch happen immediately or when the process will return to user mode ? > I guess it wont happen immediately as it is non-preemptive. > Thank, > Rahul. > > > > > -----Original Message----- > From: Patwardhan, Aniruddha [mailto:Aniruddha_Patwardhan@bmc.com] > Sent: Monday, October 21, 2002 12:06 PM > To: Sonawane, Rahul (Rahul) > Cc: kernelnewbies@nl.linux.org > Subject: RE: Linux Scheduler > > > Interrupt handling as explained in Bach will illustrate this in more > details, with diagram > > -Aniruddha > -----Original Message----- > From: Ketan Mukadam [mailto:kmukadam@neomagic.com] > Sent: Monday, October 21, 2002 11:47 AM > To: Sonawane, Rahul (Rahul) > Cc: kernelnewbies@nl.linux.org > Subject: Re: Linux Scheduler > > > > The timer interrupt service routine will get executed in the current > process context. Kernel non-preemptibility does not include interrupts. > > Regds > Ketan > > Sonawane, Rahul (Rahul) wrote: > >>Hi, >> I have some questions on linux scheduling. Linux kernel is > > non-preemptive in kernel mode ..right. Now it is executing > >>in the kernel mode and a timer interrupt occurs ,Does is preempt ..I mean > > the timer interrupt is of utmost priority it has > >>to get processed. Please can someone enlighten me about what will happen > > if the timer interrupt occurs when it is executing > >>in kernel mode on behalf of some process. >> >>Thanks in advance, >>Rahul >> >> >>-- >>Kernelnewbies: Help each other learn about the Linux kernel. >>Archive: http://mail.nl.linux.org/kernelnewbies/ >>FAQ: http://kernelnewbies.org/faq/ >> >> > > > -- "Only the paranoid survives." --- Andy Grove -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
