On Thu, May 11, 2017 at 02:57:24PM +0200, Markus Trippelsdorf wrote: > Using the new Kyber mq scheduler brings my system to a halt as soon as it > starts swapping. The swap partition resides on an SSD and is the only > partition in use on that drive. > Symptoms are stuttering sound and non moving mouse pointer. After a > while the monitor switches off, because it gets no signal anymore. > At which point only a hard reset will bring the system back. > > "none" works fine. Thanks for testing, I'm taking a look to see if there's anything special about the swap path that would trigger this. In the meantime, if you swapoff your swap partition and do some I/O on it, what happens? Here's a first-order guess at a fio job you could run: fio --group_reporting --filename=$partition \ --name swapin --numjobs=8 --ioengine=sync --rw=randread \ --name swapout --numjobs=4 --ioengine=libaio --iodepth=8 --rw=randwrite Interesting to note is that wbt, which Kyber borrowed ideas from, treats kswapd specially, allowing it to queue more I/O than other processes. I wonder if we need to do the same in Kyber.
