>Subject: Re: [PATCH v2 rdma-next 0/5] Introduce a DMA block iterator > >On Fri, Apr 19, 2019 at 08:43:48AM -0500, Shiraz Saleem wrote: >> From: "Shiraz Saleem" <shiraz.saleem@xxxxxxxxx> >> >> This patch set is aiming to allow drivers to leverage a new DMA block >> iterator to get contiguous aligned memory blocks within their HW >> supported page sizes. The motivation for this work comes from the >> discussion in [1]. >> >> The first patch introduces a new umem API that allows drivers to find >> a best supported page size to use for the MR, from a bitmap of HW >> supported page sizes. >> >> The second patch introduces a new DMA block iterator that returns >> allows drivers to get aligned DMA addresses within a HW supported page size. >> >> The third patch and fouth patch removes the dependency of i40iw and >> bnxt_re drivers on the hugetlb flag. The new core APIs are called in >> these drivers to get huge page size aligned addresses if the MR is backed by >huge pages. >> >> The sixth patch removes the hugetlb flag from IB core. >> >> Please note that mixed page portion of the algorithm and bnxt_re >> update in patch #4 have not been tested on hardware. >> >> [1] https://patchwork.kernel.org/patch/10499753/ >> >> RFC-->v0: >> * Add to scatter table by iterating a limited sized page list. >> * Updated driver call sites to use the for_each_sg_page iterator >> variant where applicable. >> * Tweaked algorithm in ib_umem_find_single_pg_size and >ib_umem_next_phys_iter >> to ignore alignment of the start of first SGE and end of the last SGE. >> * Simplified ib_umem_find_single_pg_size on offset alignments checks for >> user-space virtual and physical buffer. >> * Updated ib_umem_start_phys_iter to do some pre-computation >> for the non-mixed page support case. >> * Updated bnxt_re driver to use the new core APIs and remove its >> dependency on the huge tlb flag. >> * Fixed a bug in computation of sg_phys_iter->phyaddr in >ib_umem_next_phys_iter. >> * Drop hugetlb flag usage from RDMA subsystem. >> * Rebased on top of for-next. >> >> v0-->v1: >> * Remove the patches that update driver to use for_each_sg_page variant >> to iterate in the SGE. This is sent as a seperate series using >> the for_each_sg_dma_page variant. >> * Tweak ib_umem_add_sg_table API defintion based on maintainer feedback. >> * Cache number of scatterlist entries in umem. >> * Update function headers for ib_umem_find_single_pg_size and >ib_umem_next_phys_iter. >> * Add sanity check on supported_pgsz in ib_umem_find_single_pg_size. >> >> v1-->v2: >> *Removed page combining patch as it was sent stand alone. >> *__fls on pgsz_bitmap as opposed to fls64 since it's an unsigned long. >> *rename ib_umem_find_pg_bit() --> rdma_find_pg_bit() and moved to >> ib_verbs.h *rename ib_umem_find_single_pg_size() --> >> ib_umem_find_best_pgsz() *New flag IB_UMEM_VA_BASED_OFFSET for >ib_umem_find_best_pgsz API for HW that uses least significant bits >> of VA to indicate start offset into DMA list. >> *rdma_find_pg_bit() logic is re-written and simplified. It can support input of 0 or 1 >dma addr cases. >> *ib_umem_find_best_pgsz() optimized to be less computationally expensive >running rdma_find_pg_bit() only once. >> *rdma_for_each_block() is the new re-designed DMA block iterator which is more >in line with for_each_sg_dma_page()iterator. >> *rdma_find_mixed_pg_bit() logic for interior SGE's accounting for start and end >dma address. >> *remove i40iw specific enums for supported page size *remove vma_list >> form ib_umem_get() > >Gal? Does this work for you now? > >At this point this only impacts two drivers that are presumably tested by their >authors, so I'd like to merge it to finally get rid of the hugetlb flag.. But EFA will >need to use it too > Selvin - It would be good if you could retest this version of the series with bnxt_re too since there were some design changes to core algorithms. Shiraz
