On Tue, Aug 10, 2021 at 03:52:25PM -0500, Tom Lendacky via iommu wrote: > I think the atomic pool is used by the NVMe driver. My understanding is > that driver will do a dma_alloc_coherent() from interrupt context, so it > needs to use GFP_ATOMIC. The pool was created because dma_alloc_coherent() > would perform a set_memory_decrypted() call, which can sleep. The pool > eliminates that issue (David can correct me if I got that wrong). Not just the NVMe driver. We have plenty of drivers doing that, just do a quick grep for dma_alloc_* dma_poll_alloc, dma_pool_zalloc with GFP_ATOMIC (and that won't even find multi-line strings).
