Re: [dpdk-dev] [PATCH] eal: don't advertise a physical address when no hugepages

[Jan Blunck <jblunck@infradead.org>]

On Fri, Jun 9, 2017 at 10:29 AM, Olivier Matz <olivier.matz@6wind.com> wrote:
> When populating a mempool with a virtual memory area, the mempool
> library expects to be able to get the physical address of each page.
>
> When started with --no-huge, the physical addresses may not be available
> because the pages are not locked in memory. It sometimes returns
> RTE_BAD_PHYS_ADDR, which makes the mempool_populate() function to fail.
>
> This was working before the commit cdc242f260e7 ("eal/linux: support
> running as unprivileged user"), because rte_mem_virt2phy() was returning
> 0 instead of RTE_BAD_PHYS_ADDR, which was seen as a valid physical
> address.
>
> Since --no-huge is a debug function that breaks the support of physical
> drivers, always set physical addresses to RTE_BAD_PHYS_ADDR in memzones
> or in rte_mem_virt2phy(), and ensure that mempool won't complain in that
> case.
>
> Fixes: cdc242f260e7 ("eal/linux: support running as unprivileged user")
>
> CC: stable@dpdk.org
> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> ---
>  lib/librte_eal/common/eal_common_memzone.c | 5 ++++-
>  lib/librte_eal/linuxapp/eal/eal_memory.c   | 7 +++++++
>  lib/librte_mempool/rte_mempool.c           | 2 +-
>  3 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_memzone.c b/lib/librte_eal/common/eal_common_memzone.c
> index 3026e36b8..c465c8fc2 100644
> --- a/lib/librte_eal/common/eal_common_memzone.c
> +++ b/lib/librte_eal/common/eal_common_memzone.c
> @@ -251,7 +251,10 @@ memzone_reserve_aligned_thread_unsafe(const char *name, size_t len,
>
>         mcfg->memzone_cnt++;
>         snprintf(mz->name, sizeof(mz->name), "%s", name);
> -       mz->phys_addr = rte_malloc_virt2phy(mz_addr);
> +       if (rte_eal_has_hugepages())
> +               mz->phys_addr = rte_malloc_virt2phy(mz_addr);
> +       else
> +               mz->phys_addr = RTE_BAD_PHYS_ADDR;

Since you set phys_addrs_available to false rte_malloc_virt2phy()
anyway returns RTE_BAD_PHYS_ADDR so I believe the conditional isn't
necessary here.

Rest of the patch looks good to me.

>         mz->addr = mz_addr;
>         mz->len = (requested_len == 0 ? elem->size : requested_len);
>         mz->hugepage_sz = elem->ms->hugepage_sz;
> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
> index 9c9baf628..1c99852f6 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> @@ -108,6 +108,13 @@ test_phys_addrs_available(void)
>         if (rte_xen_dom0_supported())
>                 return;
>
> +       if (!rte_eal_has_hugepages()) {
> +               RTE_LOG(ERR, EAL,
> +                       "Started without hugepages support, physical addresses not available\n");
> +               phys_addrs_available = false;
> +               return;
> +       }
> +
>         physaddr = rte_mem_virt2phy(&tmp);
>         if (physaddr == RTE_BAD_PHYS_ADDR) {
>                 RTE_LOG(ERR, EAL,
> diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
> index f65310f60..6fc3c9c7c 100644
> --- a/lib/librte_mempool/rte_mempool.c
> +++ b/lib/librte_mempool/rte_mempool.c
> @@ -476,7 +476,7 @@ rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
>                 /* required for xen_dom0 to get the machine address */
>                 paddr = rte_mem_phy2mch(-1, paddr);
>
> -               if (paddr == RTE_BAD_PHYS_ADDR) {
> +               if (paddr == RTE_BAD_PHYS_ADDR && rte_eal_has_hugepages()) {
>                         ret = -EINVAL;
>                         goto fail;
>                 }
> --
> 2.11.0
>