Fwd: [ewg] Re: [PATCH v3] mlx4_ib: Optimize hugetlab pages support

[Olga Shern (Voltaire)]

Vlad,

Can you please replase mlx4_1070-optimize-huge_tlb.patch
with Yossi's patch. It fixes Eli's patch.

Thanks
Olga


---------- Forwarded message ----------
From: Yossi Etigin <yosefe at voltaire.com>
Date: Mon, Mar 30, 2009 at 6:49 PM
Subject: [ewg] Re: [PATCH v3] mlx4_ib: Optimize hugetlab pages support
To: Eli Cohen <eli at mellanox.co.il>
Cc: Roland Dreier <rdreier at cisco.com>, ewg
<ewg at lists.openfabrics.org>, general-list
<general at lists.openfabrics.org>


Eli Cohen wrote:
>
> Since Linux may not merge adjacent pages into a single scatter entry through
> calls to dma_map_sg(), we check the special case of hugetlb pages which are
> likely to be mapped to coniguous dma addresses and if they are, take advantage
> of this. This will result in a significantly lower number of MTT segments used
> for registering hugetlb memory regions.
>

How about the one below - it fixes bugzilla #1569 (fix mapping for
size that is not
on page boundary):

---

Since Linux may not merge adjacent pages into a single scatter entry through
calls to dma_map_sg(), we check the special case of hugetlb pages which are
likely to be mapped to coniguous dma addresses and if they are, take advantage
of this. This will result in a significantly lower number of MTT segments used
for registering hugetlb memory regions.

Signed-off-by: Eli Cohen <eli at mellanox.co.il>
---
drivers/infiniband/hw/mlx4/mr.c |   81 ++++++++++++++++++++++++++++++++++----
1 files changed, 72 insertions(+), 9 deletions(-)

Index: b/drivers/infiniband/hw/mlx4/mr.c
===================================================================
--- a/drivers/infiniband/hw/mlx4/mr.c   2008-11-19 21:32:15.000000000 +0200
+++ b/drivers/infiniband/hw/mlx4/mr.c   2009-03-30 18:29:55.000000000 +0300
@@ -119,6 +119,70 @@ out:
       return err;
}

+static int handle_hugetlb_user_mr(struct ib_pd *pd, struct mlx4_ib_mr *mr,
+                                 u64 start, u64 virt_addr, int access_flags)
+{
+#if defined(CONFIG_HUGETLB_PAGE) && !defined(__powerpc__) && !defined(__ia64__)
+       struct mlx4_ib_dev *dev = to_mdev(pd->device);
+       struct ib_umem_chunk *chunk;
+       unsigned dsize;
+       dma_addr_t daddr;
+       unsigned cur_size = 0;
+       dma_addr_t uninitialized_var(cur_addr);
+       int n;
+       struct ib_umem  *umem = mr->umem;
+       u64 *arr;
+       int err = 0;
+       int i;
+       int j = 0;
+       int off = start & (HPAGE_SIZE - 1);
+
+       n = DIV_ROUND_UP(off + umem->length, HPAGE_SIZE);
+       arr = kmalloc(n * sizeof *arr, GFP_KERNEL);
+       if (!arr)
+               return -ENOMEM;
+
+       list_for_each_entry(chunk, &umem->chunk_list, list)
+               for (i = 0; i < chunk->nmap; ++i) {
+                       daddr = sg_dma_address(&chunk->page_list[i]);
+                       dsize = sg_dma_len(&chunk->page_list[i]);
+                       if (!cur_size) {
+                               cur_addr = daddr;
+                               cur_size = dsize;
+                       } else if (cur_addr + cur_size != daddr) {
+                               err = -EINVAL;
+                               goto out;
+                       } else
+                               cur_size += dsize;
+
+                       if (cur_size > HPAGE_SIZE) {
+                               err = -EINVAL;
+                               goto out;
+                       } else if (cur_size == HPAGE_SIZE) {
+                               cur_size = 0;
+                               arr[j++] = cur_addr;
+                       }
+               }
+
+       if (cur_size) {
+               arr[j++] = cur_addr;
+       }
+
+       err = mlx4_mr_alloc(dev->dev, to_mpd(pd)->pdn, virt_addr, umem->length,
+                           convert_access(access_flags), n,
HPAGE_SHIFT, &mr->mmr);
+       if (err)
+               goto out;
+
+       err = mlx4_write_mtt(dev->dev, &mr->mmr.mtt, 0, n, arr);
+
+out:
+       kfree(arr);
+       return err;
+#else
+       return -ENOSYS;
+#endif
+}
+
struct ib_mr *mlx4_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
                                 u64 virt_addr, int access_flags,
                                 struct ib_udata *udata)
@@ -140,17 +204,20 @@ struct ib_mr *mlx4_ib_reg_user_mr(struct
               goto err_free;
       }

-       n = ib_umem_page_count(mr->umem);
-       shift = ilog2(mr->umem->page_size);
-
-       err = mlx4_mr_alloc(dev->dev, to_mpd(pd)->pdn, virt_addr, length,
-                           convert_access(access_flags), n, shift, &mr->mmr);
-       if (err)
-               goto err_umem;
-
-       err = mlx4_ib_umem_write_mtt(dev, &mr->mmr.mtt, mr->umem);
-       if (err)
-               goto err_mr;
+       if (!mr->umem->hugetlb ||
+           handle_hugetlb_user_mr(pd, mr, start, virt_addr, access_flags)) {
+               n = ib_umem_page_count(mr->umem);
+               shift = ilog2(mr->umem->page_size);
+
+               err = mlx4_mr_alloc(dev->dev, to_mpd(pd)->pdn,
virt_addr, length,
+                                   convert_access(access_flags), n,
shift, &mr->mmr);
+               if (err)
+                       goto err_umem;
+
+               err = mlx4_ib_umem_write_mtt(dev, &mr->mmr.mtt, mr->umem);
+               if (err)
+                       goto err_mr;
+       }

       err = mlx4_mr_enable(dev->dev, &mr->mmr);
       if (err)
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