On 17-Apr-18 3:48 AM, Yongseok Koh wrote:

On Apr 11, 2018, at 5:30 AM, Anatoly Burakov <anatoly.bura...@intel.com> wrote:

Reduce dependency on internal details of EAL memory subsystem, and
simplify code.

Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com>
Tested-by: Santosh Shukla <santosh.shu...@caviumnetworks.com>
Tested-by: Hemant Agrawal <hemant.agra...@nxp.com>
Tested-by: Gowrishankar Muthukrishnan <gowrishanka...@linux.vnet.ibm.com>
---
drivers/net/mlx5/mlx5_mr.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c
index 58afeb7..c96e134 100644
--- a/drivers/net/mlx5/mlx5_mr.c
+++ b/drivers/net/mlx5/mlx5_mr.c
@@ -234,10 +234,9 @@ struct mlx5_mr *
mlx5_mr_new(struct rte_eth_dev *dev, struct rte_mempool *mp)
{
        struct priv *priv = dev->data->dev_private;
-       const struct rte_memseg *ms = rte_eal_get_physmem_layout();
+       const struct rte_memseg *ms;
        uintptr_t start;
        uintptr_t end;
-       unsigned int i;
        struct mlx5_mr *mr;

        mr = rte_zmalloc_socket(__func__, sizeof(*mr), 0, mp->socket_id);
@@ -261,17 +260,15 @@ mlx5_mr_new(struct rte_eth_dev *dev, struct rte_mempool 
*mp)
        /* Save original addresses for exact MR lookup. */
        mr->start = start;
        mr->end = end;
+
        /* Round start and end to page boundary if found in memory segments. */
-       for (i = 0; (i < RTE_MAX_MEMSEG) && (ms[i].addr != NULL); ++i) {
-               uintptr_t addr = (uintptr_t)ms[i].addr;
-               size_t len = ms[i].len;
-               unsigned int align = ms[i].hugepage_sz;
+       ms = rte_mem_virt2memseg((void *)start);
+       if (ms != NULL)
+               start = RTE_ALIGN_FLOOR(start, ms->hugepage_sz);
+       ms = rte_mem_virt2memseg((void *)end);
+       if (ms != NULL)
+               end = RTE_ALIGN_CEIL(end, ms->hugepage_sz);

It is buggy. The memory region is [start, end), so if the memseg of 'end' isn't
allocated yet, the returned ms will have zero entries and this will make 'end'
zero. Instead, the following will be fine.

diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c
index fdf7b3e88..39bbe2481 100644
--- a/drivers/net/mlx5/mlx5_mr.c
+++ b/drivers/net/mlx5/mlx5_mr.c
@@ -265,9 +265,7 @@ mlx5_mr_new(struct rte_eth_dev *dev, struct rte_mempool *mp)
         ms = rte_mem_virt2memseg((void *)start, NULL);
         if (ms != NULL)
                 start = RTE_ALIGN_FLOOR(start, ms->hugepage_sz);
-       ms = rte_mem_virt2memseg((void *)end, NULL);
-       if (ms != NULL)
-               end = RTE_ALIGN_CEIL(end, ms->hugepage_sz);
+       end = RTE_ALIGN_CEIL(end, ms->hugepage_sz);

         DRV_LOG(DEBUG,
                 "port %u mempool %p using start=%p end=%p size=%zu for memory"

Same for mlx4. Please fix both mlx5 and mlx4 so that we can verify the new 
design.

However, this code block will be removed eventually. I've done a patchset to
accommodate your memory hotplug design and I'll send it out soon.

Hi,

Thanks for raising this. I'll submit a patch shortly.



Thanks in advance.
Yongseok

-               if ((start > addr) && (start < addr + len))
-                       start = RTE_ALIGN_FLOOR(start, align);
-               if ((end > addr) && (end < addr + len))
-                       end = RTE_ALIGN_CEIL(end, align);
-       }
        DRV_LOG(DEBUG,
                "port %u mempool %p using start=%p end=%p size=%zu for memory"
                " region",
--
2.7.4




--
Thanks,
Anatoly

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