On Tue, Feb 16, 2021 at 05:14:55PM +0900, Tomasz Figa wrote: > When working on the videobuf2 integration with Sergey I noticed that > we always pass 0 as DMA attrs here, which removes the ability for > drivers to use DMA_ATTR_ALLOC_SINGLE_PAGES. > > It's quite important from a system stability point of view, because by > default the iommu_dma allocator would prefer big order allocations for > TLB locality reasons. For many devices, though, it doesn't really > affect the performance, because of random access patterns, so single > pages are good enough and reduce the risk of allocation failures or > latency due to fragmentation. > > Do you think we could add the attrs parameter to the > dma_alloc_noncontiguous() API? Yes, we could probably do that.
