On Thu 2018-01-11 19:38:45, Sergey Senozhatsky wrote: > On (01/11/18 10:34), Petr Mladek wrote: > [..] > > > except that handing off a console_sem to atomic task when there > > > is O(logbuf) > watchdog_thresh is a regression, basically... > > > it is what it is. > > > > How this could be a regression? Is not the victim that handles > > other printk's random? What protected the atomic task to > > handle the other printks before this patch? > > the non-atomic -> atomic context console_sem transfer. we previously > would have kept the console_sem owner to its non-atomic owner. we now > will make sure that if printk from atomic context happens then it will > make it to console_unlock() loop. > emphasis on O(logbuf) > watchdog_thresh. Sergey, please, why do you completely and repeatedly ignore that argument about statistical effects? Yes, the above scenario is possible. But Steven's patch might also move the owner from atomic context to a non-atomic one. The chances should be more or less equal. The main advantage is that the owner is moved. This should statistically lower the chance of a soft-lockup. > > > Or do you have a system that started to suffer from softlockups > > with this patchset and did not do this before? > [..] > > Do you know about any system where this patch made the softlockup > > deterministically or statistically more likely, please? > > I have explained many, many times why my boards die just like before. > why would I bother collecting any numbers... Is it with your own printk stress tests or during "normal" work? If it is during a normal work, is there any chance that we could have a look at the logs? Best Regards, Petr -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
