how can we wake up some process which is scheduled?
hi all: There is a kernel API, schedule_timeout_interruptible. since it has the name interruptible, who and how can we interrupt this task? suppose A use schedule_timeout_interruptible for 20s period and B found something and he want to wake up A within this 20s period. -- Regards, ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: how can we wake up some process which is scheduled?
On Tue, Dec 13, 2011 at 10:44 AM, loody milo...@gmail.com wrote: hi all: There is a kernel API, schedule_timeout_interruptible. since it has the name interruptible, who and how can we interrupt this task? suppose A use schedule_timeout_interruptible for 20s period and B found something and he want to wake up A within this 20s period. I think it's related to hardware interrupts, not other tasks. So a process waiting for a timer can be interrupted by a signal (there's a switch between process context and interrupt context). Take a look at schedule_timeout help page [0]. Notice the TASK_UNINTERRUPTIBLE and TASK_INTERRUPTIBLE sections. [0] http://kernel.org/doc/htmldocs/device-drivers/API-schedule-timeout.html -- Alexandru Juncu ROSEdu http://rosedu.org ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: how can we wake up some process which is scheduled?
Hi loody, On Tue, Dec 13, 2011 at 12:44 AM, loody milo...@gmail.com wrote: hi all: There is a kernel API, schedule_timeout_interruptible. since it has the name interruptible, who and how can we interrupt this task? suppose A use schedule_timeout_interruptible for 20s period and B found something and he want to wake up A within this 20s period. You send the task a signal. The API for doing this has a rather unfortunate name, and is called kill from user-space. From kernel space, you can use kill_pid_info, or kill_proc_info. kill_pid_info is what's called to send SIGALARM when an itimer expires. Although using signals in kernel space is fairly rare, it's typically a user-space to kernel-space thing, not a kernel-space to kernel-space thing. In kernel space, I would generally use something like a timed semaphore (down_timeout). -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
