On Tue, Oct 15, 2024 at 03:40:26PM +0800, Ming Lei wrote: > > Yes, active_cacheline_insert only complains for FROM_DEVICE or > > BIDIRECTIONAL mappings. I can't see how raid 1 would trigger that > > given that it only reads from one leg at a time. > > > > Ming, can you look a bit more into what is happening here? > > All should be READ IO which is FROM_DEVICE, please see my reply: Yes, reads translate to DMA_FROM_DEVICE. > https://lore.kernel.org/linux-block/Zw3MZrK_l7DuFfFd@fedora/ > > And the raid1 warning is actually from raid1_sync_request(). In that case the warnings are perfectly valid because the I/O patterns will create data corruption on non-coherent architectures. For direct I/O from userspace the kernel can't prevent it, but for raid1 we should be able to do something better. As raid1_sync_request is a convoluted and undocumented mess I don't have a straigh shot answer to what it is doing (wrong) and how to fix it unfortunately. > > > Thanks, > Ming ---end quoted text---
