Hi Greg, Thanks for your response. On Tue, May 17, 2016 at 7:20 PM, Greg KH <greg@xxxxxxxxx> wrote: > On Tue, May 17, 2016 at 06:55:07PM -0400, Jerrin Shaji George wrote: >> Hi All, >> >> I wanted help with a piece of code that I have been working on. >> >> Please see - >> >> https://gist.github.com/jerrinsg/333e584d1f65dc95b9f13b61dcebdaa7 >> >> I have written two function, migrate_to and migrate_back. migrate_to is used >> to remove a process from the run queue, and migrate_back is used to insert this >> process back into the run queue. >> >> The gist is from a taken from a larger project, where we are working on building >> a mechanism to support thread migration across heterogeneous processors. >> migrate_to_call() will be called by a thread which wants to remove itself from >> the run queue (hence, it will pass the current task struct as the migration >> argument). Once the other processor completes execution of the assigned task, it >> will interrupt the main processor, which runs an interrupt handler, which in >> turn calls the migrate_back_call() function. It passes the task struct of the >> process that was removed from the run queue earlier to this function. >> >> This mechanism works fine the first few times, but when this process is repeated >> many times in a loop, I am seeing a run queue corruption: >> https://gist.github.com/jerrinsg/0ab09cd435d8d2cb6ae692c7e6f4f26b >> >> Is there anything wrong in the process dequeue or enqueue function that I have >> written? Please help! > > volatile doesn't mean what you think it does, please don't use it in the > kernel. > This flag was to be used for synchronization. I will change this. > And why are you using "raw_spin_lock()"? I used this seeing other usage in sched/core.c. Can please you let me know if I should instead use a different function to lock the run queue? >> Kernel used: Linux 3.13 > > Wow that's obsolete and buggy, why use such an old thing? This is the codebase that I inherited. Once I get the basic prototype working, I will be working to port it to a newer version of the kernel. > > greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
