On Fri, Jan 03, 2020 at 08:38:51PM +0200, Liran Alon wrote: > Actually after re-reading AMD Optimization Guide SDM, I see it is > guaranteed that: “Write-combining is closed if all 64 bytes of the > write buffer are valid”. And this is indeed always the case for AWS > ENA LLQ. Because as can be seen at ena_com_config_llq_info(), > desc_list_entry_size is either 128, 192 or 256. i.e. Always a > multiple of 64 bytes. So this explains why this wasn’t an issue in > production. That makes a lot of sense So, the problem with defining WC in the kernel memory model still remains, but it is back to a theoretical one. Jason
