Mikhail Gavrilov <mikhail.v.gavrilov@xxxxxxxxx> writes: > On Tue, 23 Jul 2019 at 10:08, Huang, Ying <ying.huang@xxxxxxxxx> wrote: >> >> Thanks! I have found another (easier way) to reproduce the panic. >> Could you try the below patch on top of v5.2-rc2? It can fix the panic >> for me. >> > > Thanks! Amazing work! The patch fixes the issue completely. The system > worked at a high load of 16 hours without failures. Thanks a lot for your help! Hi, Matthew and Kirill, I think we can fold this fix patch into your original patch and try again. > But still seems to me that page cache is being too actively crowded > out with a lack of memory. Since, in addition to the top speed SSD on > which the swap is located, there is also the slow HDD in the system > that just starts to rustle continuously when swap being used. It would > seem better to push some of the RAM onto a fast SSD into the swap > partition than to leave the slow HDD without a cache. > > https://imgur.com/a/e8TIkBa > > But I am afraid it will be difficult to implement such an algorithm > that analyzes the waiting time for the file I/O and waiting for paging > (memory) and decides to leave parts in memory where the waiting time > is more higher it would be more efficient for systems with several > drives with access speeds can vary greatly. By waiting time I mean > waiting time reading/writing to storage multiplied on the count of > hits. Thus, we will not just keep in memory the most popular parts of > the memory/disk, but also those parts of which read/write where was > most costly. Yes. This is a valid problem. I remember Johannes has a solution long ago, but I don't know why he give up that. Some information can be found in the following URL. https://lwn.net/Articles/690079/ Best Regards, Huang, Ying > -- > Best Regards, > Mike Gavrilov.
