[dpdk-dev] [RFC 01/11] mem: allow memseg lists to be marked as external

Alejandro Lucero alejandro.lucero at netronome.com
Tue Jul 10 13:18:30 CEST 2018


On Fri, Jul 6, 2018 at 2:17 PM, Anatoly Burakov <anatoly.burakov at intel.com>
wrote:

> When we allocate and use DPDK memory, we need to be able to
> differentiate between DPDK hugepage segments and segments that
> were made part of DPDK but are externally allocated. Add such
> a property to memseg lists.
>
> Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
> ---
>  lib/librte_eal/common/eal_common_memory.c     | 51 ++++++++++++++++---
>  .../common/include/rte_eal_memconfig.h        |  1 +
>  lib/librte_eal/common/malloc_heap.c           |  2 +-
>  3 files changed, 47 insertions(+), 7 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_memory.c
> b/lib/librte_eal/common/eal_common_memory.c
> index 4f0688f9d..835bbffb6 100644
> --- a/lib/librte_eal/common/eal_common_memory.c
> +++ b/lib/librte_eal/common/eal_common_memory.c
> @@ -24,6 +24,21 @@
>  #include "eal_private.h"
>  #include "eal_internal_cfg.h"
>
> +/* forward declarations for memseg walk functions. we support external
> segments,
> + * but for some functionality to work, we need to either skip or not skip
> + * external segments. for example, while we expect for virt2memseg to
> return a
> + * valid memseg even though it's an external memseg, for regular memseg
> walk we
> + * want to skip those because the expectation is that we will only walk
> the
> + * DPDK allocated memory.
> + */
>

I do not clear understand when external segments can be used along with
hugepages segments, but if this is a possibility, should not we support
memseg walk for just external segments and also to allow any walk type as
an API? If I'm right, it seems just memseg walk skipping external memsegs
can be invoked from other files.


> +static int
> +memseg_list_walk(rte_memseg_list_walk_t func, void *arg, bool
> skip_external);
> +static int
> +memseg_walk(rte_memseg_walk_t func, void *arg, bool skip_external);
> +static int
> +memseg_contig_walk(rte_memseg_contig_walk_t func, void *arg,
> +               bool skip_external);
> +
>  /*
>   * Try to mmap *size bytes in /dev/zero. If it is successful, return the
>   * pointer to the mmap'd area and keep *size unmodified. Else, retry
> @@ -621,9 +636,9 @@ rte_mem_iova2virt(rte_iova_t iova)
>          * as we know they are PA-contiguous as well
>          */
>         if (internal_config.legacy_mem)
> -               rte_memseg_contig_walk(find_virt_legacy, &vi);
> +               memseg_contig_walk(find_virt_legacy, &vi, false);
>         else
> -               rte_memseg_walk(find_virt, &vi);
> +               memseg_walk(find_virt, &vi, false);
>
>         return vi.virt;
>  }
> @@ -787,8 +802,8 @@ rte_mem_lock_page(const void *virt)
>         return mlock((void *)aligned, page_size);
>  }
>
> -int __rte_experimental
> -rte_memseg_contig_walk(rte_memseg_contig_walk_t func, void *arg)
> +static int
> +memseg_contig_walk(rte_memseg_contig_walk_t func, void *arg, bool
> skip_external)
>  {
>         struct rte_mem_config *mcfg = rte_eal_get_configuration()->
> mem_config;
>         int i, ms_idx, ret = 0;
> @@ -803,6 +818,8 @@ rte_memseg_contig_walk(rte_memseg_contig_walk_t func,
> void *arg)
>
>                 if (msl->memseg_arr.count == 0)
>                         continue;
> +               if (skip_external && msl->external)
> +                       continue;
>
>                 arr = &msl->memseg_arr;
>
> @@ -837,7 +854,13 @@ rte_memseg_contig_walk(rte_memseg_contig_walk_t
> func, void *arg)
>  }
>
>  int __rte_experimental
> -rte_memseg_walk(rte_memseg_walk_t func, void *arg)
> +rte_memseg_contig_walk(rte_memseg_contig_walk_t func, void *arg)
> +{
> +       return memseg_contig_walk(func, arg, true);
> +}
> +
> +static int
> +memseg_walk(rte_memseg_walk_t func, void *arg, bool skip_external)
>  {
>         struct rte_mem_config *mcfg = rte_eal_get_configuration()->
> mem_config;
>         int i, ms_idx, ret = 0;
> @@ -852,6 +875,8 @@ rte_memseg_walk(rte_memseg_walk_t func, void *arg)
>
>                 if (msl->memseg_arr.count == 0)
>                         continue;
> +               if (skip_external && msl->external)
> +                       continue;
>
>                 arr = &msl->memseg_arr;
>
> @@ -875,7 +900,13 @@ rte_memseg_walk(rte_memseg_walk_t func, void *arg)
>  }
>
>  int __rte_experimental
> -rte_memseg_list_walk(rte_memseg_list_walk_t func, void *arg)
> +rte_memseg_walk(rte_memseg_walk_t func, void *arg)
> +{
> +       return memseg_walk(func, arg, true);
> +}
> +
> +static int
> +memseg_list_walk(rte_memseg_list_walk_t func, void *arg, bool
> skip_external)
>  {
>         struct rte_mem_config *mcfg = rte_eal_get_configuration()->
> mem_config;
>         int i, ret = 0;
> @@ -888,6 +919,8 @@ rte_memseg_list_walk(rte_memseg_list_walk_t func,
> void *arg)
>
>                 if (msl->base_va == NULL)
>                         continue;
> +               if (skip_external && msl->external)
> +                       continue;
>
>                 ret = func(msl, arg);
>                 if (ret < 0) {
> @@ -904,6 +937,12 @@ rte_memseg_list_walk(rte_memseg_list_walk_t func,
> void *arg)
>         return ret;
>  }
>
> +int __rte_experimental
> +rte_memseg_list_walk(rte_memseg_list_walk_t func, void *arg)
> +{
> +       return memseg_list_walk(func, arg, true);
> +}
> +
>  /* init memory subsystem */
>  int
>  rte_eal_memory_init(void)
> diff --git a/lib/librte_eal/common/include/rte_eal_memconfig.h
> b/lib/librte_eal/common/include/rte_eal_memconfig.h
> index aff0688dd..4e8720ba6 100644
> --- a/lib/librte_eal/common/include/rte_eal_memconfig.h
> +++ b/lib/librte_eal/common/include/rte_eal_memconfig.h
> @@ -30,6 +30,7 @@ struct rte_memseg_list {
>                 uint64_t addr_64;
>                 /**< Makes sure addr is always 64-bits */
>         };
> +       bool external; /**< true if this list points to external memory */
>         int socket_id; /**< Socket ID for all memsegs in this list. */
>         uint64_t page_sz; /**< Page size for all memsegs in this list. */
>         volatile uint32_t version; /**< version number for multiprocess
> sync. */
> diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/
> malloc_heap.c
> index d6cf3af81..8a1f54905 100644
> --- a/lib/librte_eal/common/malloc_heap.c
> +++ b/lib/librte_eal/common/malloc_heap.c
> @@ -631,7 +631,7 @@ malloc_heap_free(struct malloc_elem *elem)
>         ret = 0;
>
>         /* ...of which we can't avail if we are in legacy mode */
> -       if (internal_config.legacy_mem)
> +       if (internal_config.legacy_mem || msl->external)
>                 goto free_unlock;
>
>         /* check if we can free any memory back to the system */
> --
> 2.17.1
>


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