On Wed, 1 Nov 2017 09:30:05 +0100 Vlastimil Babka <vbabka@xxxxxxx> wrote: > > But still, it seems to me that the scheme only works as long as there > are printk()'s coming with some reasonable frequency. There's still a > corner case when a storm of printk()'s can come that will fill the ring > buffers, and while during the storm the printing will be distributed > between CPUs nicely, the last unfortunate CPU after the storm subsides > will be left with a large accumulated buffer to print, and there will be > no waiters to take over if there are no more printk()'s coming. What > then, should it detect such situation and defer the flushing? No! If such a case happened, that means the system is doing something really stupid. Btw, each printk that takes over, does one message, so the last one to take over, shouldn't have a full buffer anyway. But still, if you have such a hypothetical situation, the system should just crash. The printk is still bounded by the length of the buffer. Although it is slow, it will finish. Which is not the case with the current situation. And the current situation (as which this patch demonstrates) does happen today and is not hypothetical. -- Steve -- 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>
