On 2024-05-11 16:43 Jens Axboe wrote: > On 5/10/24 11:52 PM, Chenliang Li wrote: >> Registered buffers are stored and processed in the form of bvec array, >> each bvec element typically points to a PAGE_SIZE page but can also work >> with hugepages. Specifically, a buffer consisting of a hugepage is >> coalesced to use only one hugepage bvec entry during registration. >> This coalescing feature helps to save both the space and DMA-mapping time. >> >> However, currently the coalescing feature doesn't work for multi-hugepage >> buffers. For a buffer with several 2M hugepages, we still split it into >> thousands of 4K page bvec entries while in fact, we can just use a >> handful of hugepage bvecs. >> >> This patch series enables coalescing registered buffers with more than >> one hugepages. It optimizes the DMA-mapping time and saves memory for >> these kind of buffers. > This series looks much better. Do you have a stand-alone test case > for this? We should have that in liburing. Then we can also augment it > with edge cases to ensure this is all safe and sound. Thanks! Yes, I have a liburing test case, will send it as a patch in V3.
