From: Jason Gunthorpe <jgg@nvidia.com>
To: Doug Ledford <dledford@redhat.com>, <linux-rdma@vger.kernel.org>
Cc: Shiraz Saleem <shiraz.saleem@intel.com>
Subject: Re: [PATCH 01/14] RDMA/umem: Fix ib_umem_find_best_pgsz() for mappings that cross a page boundary
Date: Fri, 4 Sep 2020 19:30:29 -0300 [thread overview]
Message-ID: <20200904223029.GA454890@nvidia.com> (raw)
In-Reply-To: <1-v1-00f59ce24f1f+19f50-umem_1_jgg@nvidia.com>
On Tue, Sep 01, 2020 at 09:43:29PM -0300, Jason Gunthorpe wrote:
> It is possible for a single SGL to span an aligned boundary, eg if the SGL
> is
>
> 61440 -> 90112
>
> Then the length is 28672, which currently limits the block size to
> 32k. With a 32k page size the two covering blocks will be:
>
> 32768->65536 and 65536->98304
>
> However, the correct answer is a 128K block size which will span the whole
> 28672 bytes in a single block.
>
> Instead of limiting based on length figure out which high IOVA bits don't
> change between the start and end addresses. That is the highest useful
> page size.
>
> Fixes: 4a35339958f1 ("RDMA/umem: Add API to find best driver supported page size in an MR")
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
> drivers/infiniband/core/umem.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
> index 831bff8d52e547..120e98403c345d 100644
> --- a/drivers/infiniband/core/umem.c
> +++ b/drivers/infiniband/core/umem.c
> @@ -156,8 +156,14 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
> return 0;
>
> va = virt;
> - /* max page size not to exceed MR length */
> - mask = roundup_pow_of_two(umem->length);
> + /* The best result is the smallest page size that results in the minimum
> + * number of required pages. Compute the largest page size that could
> + * work based on VA address bits that don't change.
> + */
> + mask = pgsz_bitmap &
> + GENMASK(BITS_PER_LONG - 1,
> + bits_per((umem->length - 1 + umem->address) ^
> + umem->address));
The use of umem->address is incorrect here as well, it should be virt.
All places on the DMA side that touch address are wrong..
Jason
next prev parent reply other threads:[~2020-09-04 22:30 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-02 0:43 [PATCH 00/14] RDMA: Improve use of umem in DMA drivers Jason Gunthorpe
2020-09-02 0:43 ` [PATCH 01/14] RDMA/umem: Fix ib_umem_find_best_pgsz() for mappings that cross a page boundary Jason Gunthorpe
2020-09-02 9:24 ` Leon Romanovsky
2020-09-03 14:11 ` Saleem, Shiraz
2020-09-04 22:30 ` Jason Gunthorpe [this message]
2020-09-02 0:43 ` [PATCH 02/14] RDMA/umem: Prevent small pages from being returned by ib_umem_find_best_pgsz() Jason Gunthorpe
2020-09-02 11:51 ` Leon Romanovsky
2020-09-02 11:59 ` Jason Gunthorpe
2020-09-02 12:05 ` Leon Romanovsky
2020-09-02 16:34 ` Jason Gunthorpe
2020-09-03 14:11 ` Saleem, Shiraz
2020-09-03 14:17 ` Jason Gunthorpe
2020-09-03 14:18 ` Saleem, Shiraz
2020-09-02 0:43 ` [PATCH 03/14] RDMA/umem: Use simpler logic for ib_umem_find_best_pgsz() Jason Gunthorpe
2020-09-02 0:43 ` [PATCH 04/14] RDMA/umem: Add rdma_umem_for_each_dma_block() Jason Gunthorpe
2020-09-02 3:10 ` Miguel Ojeda
2020-09-03 14:12 ` Saleem, Shiraz
2020-09-02 0:43 ` [PATCH 05/14] RDMA/umem: Replace for_each_sg_dma_page with rdma_umem_for_each_dma_block Jason Gunthorpe
2020-09-02 0:43 ` [PATCH 06/14] RDMA/umem: Split ib_umem_num_pages() into ib_umem_num_dma_blocks() Jason Gunthorpe
2020-09-03 14:12 ` Saleem, Shiraz
2020-09-03 14:14 ` Jason Gunthorpe
2020-09-04 22:32 ` Jason Gunthorpe
2020-09-02 0:43 ` [PATCH 07/14] RDMA/qedr: Use rdma_umem_for_each_dma_block() instead of open-coding Jason Gunthorpe
2020-09-02 15:36 ` [EXT] " Michal Kalderon
2020-09-02 18:44 ` Jason Gunthorpe
2020-09-02 19:53 ` Michal Kalderon
2020-09-02 0:43 ` [PATCH 08/14] RDMA/qedr: Use ib_umem_num_dma_blocks() instead of ib_umem_page_count() Jason Gunthorpe
2020-09-02 15:35 ` [EXT] " Michal Kalderon
2020-09-02 0:43 ` [PATCH 09/14] RDMA/bnxt: Do not use ib_umem_page_count() or ib_umem_num_pages() Jason Gunthorpe
2020-09-03 4:41 ` Selvin Xavier
2020-09-02 0:43 ` [PATCH 10/14] RDMA/hns: Use ib_umem_num_dma_blocks() instead of opencoding Jason Gunthorpe
2020-09-02 0:43 ` [PATCH 11/14] RDMA/ocrdma: Use ib_umem_num_dma_blocks() instead of ib_umem_page_count() Jason Gunthorpe
2020-09-02 0:43 ` [PATCH 12/14] RDMA/pvrdma: " Jason Gunthorpe
2020-09-02 0:43 ` [PATCH 13/14] RDMA/mlx5: Use ib_umem_num_dma_blocks() Jason Gunthorpe
2020-09-02 9:07 ` Gal Pressman
2020-09-03 15:14 ` Saleem, Shiraz
2020-09-02 0:43 ` [PATCH 14/14] RDMA/umem: Rename ib_umem_offset() to ib_umem_dma_offset() Jason Gunthorpe
2020-09-02 0:51 ` Zhu Yanjun
2020-09-02 15:36 ` [EXT] " Michal Kalderon
2020-09-03 18:48 ` Jason Gunthorpe
2020-09-02 9:09 ` [PATCH 00/14] RDMA: Improve use of umem in DMA drivers Gal Pressman
2020-09-02 12:00 ` Jason Gunthorpe
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