Show a cover letter.

GET /api/covers/44222/
Content-Type: application/json
Vary: Accept

    "id": 44222,
    "url": "",
    "web_url": "",
    "project": {
        "id": 1,
        "url": "",
        "name": "DPDK",
        "link_name": "dpdk",
        "list_id": "",
        "list_email": "",
        "web_url": "",
        "scm_url": "git://",
        "webscm_url": ""
    "msgid": "<>",
    "date": "2018-09-04T13:11:35",
    "name": "[00/16] Support externally allocated memory in DPDK",
    "submitter": {
        "id": 4,
        "url": "",
        "name": "Burakov, Anatoly",
        "email": ""
    "mbox": "",
    "series": [
            "id": 1170,
            "url": "",
            "web_url": "",
            "date": "2018-09-04T13:11:35",
            "name": "Support externally allocated memory in DPDK",
            "version": 1,
            "mbox": ""
    "comments": "",
    "headers": {
        "List-Subscribe": "<>,\n\t<>",
        "Cc": ",,\n\,,\n\,,\n\,,\n\,,\n\,",
        "X-Original-To": "",
        "Date": "Tue,  4 Sep 2018 14:11:35 +0100",
        "Precedence": "list",
        "X-BeenThere": "",
        "X-Mailer": "git-send-email",
        "List-Archive": "<>",
        "To": "",
        "X-Amp-Result": "SKIPPED(no attachment in message)",
        "Errors-To": "",
        "List-Post": "<>",
        "Received": [
            "from [] (localhost [])\n\tby (Postfix) with ESMTP id 4108B231E;\n\tTue,  4 Sep 2018 15:11:58 +0200 (CEST)",
            "from ( [])\n\tby (Postfix) with ESMTP id 7399811A4\n\tfor <>; Tue,  4 Sep 2018 15:11:56 +0200 (CEST)",
            "from ([])\n\tby with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384;\n\t04 Sep 2018 06:11:55 -0700",
            "from ([])\n\tby with ESMTP; 04 Sep 2018 06:11:52 -0700",
            "from (\n\t[])\n\tby (8.14.3/8.13.6/MailSET/Hub) with ESMTP id\n\tw84DBpKu023344; Tue, 4 Sep 2018 14:11:51 +0100",
            "from (localhost [])\n\tby with ESMTP id w84DBpIj024180;\n\tTue, 4 Sep 2018 14:11:51 +0100",
            "(from aburakov@localhost)\n\tby with LOCAL id w84DBpgj024174;\n\tTue, 4 Sep 2018 14:11:51 +0100"
        "From": "Anatoly Burakov <>",
        "List-Help": "<>",
        "X-ExtLoop1": "1",
        "X-Amp-File-Uploaded": "False",
        "Sender": "\"dev\" <>",
        "List-Id": "DPDK patches and discussions <>",
        "Subject": "[dpdk-dev] [PATCH 00/16] Support externally allocated memory in DPDK",
        "List-Unsubscribe": "<>,\n\t<>",
        "Return-Path": "<>",
        "X-IronPort-AV": "E=Sophos;i=\"5.53,329,1531810800\"; d=\"scan'208\";a=\"67423754\"",
        "Delivered-To": "",
        "Message-Id": "<>",
        "X-Mailman-Version": "2.1.15"
    "content": "This is a proposal to enable using externally allocated memory\nin DPDK.\n\nIn a nutshell, here is what is being done here:\n\n- Index internal malloc heaps by NUMA node index, rather than NUMA\n  node itself (external heaps will have ID's in order of creation)\n- Add identifier string to malloc heap, to uniquely identify it\n  - Each new heap will receive a unique socket ID that will be used by\n    allocator to decide from which heap (internal or external) to\n    allocate requested amount of memory\n- Allow creating named heaps and add/remove memory to/from those heaps\n- Allocate memseg lists at runtime, to keep track of IOVA addresses\n  of externally allocated memory\n  - If IOVA addresses aren't provided, use RTE_BAD_IOVA\n- Allow malloc and memzones to allocate from external heaps\n- Allow other data structures to allocate from externall heaps\n\nThe responsibility to ensure memory is accessible before using it is\non the shoulders of the user - there is no checking done with regards\nto validity of the memory (nor could there be...).\n\nThe general approach is to create heap and add memory into it. For any\nother process wishing to use the same memory, said memory must first\nbe attached (otherwise some things will not work).\n\nA design decision was made to make multiprocess synchronization a\nmanual process. Due to underlying issues with attaching to fbarrays in\nsecondary processes, this design was deemed to be better because we\ndon't want to fail to create external heap in the primary because\nsomething in the secondary has failed when in fact we may not eve have\nwanted this memory to be accessible in the secondary in the first\nplace.\n\nUsing external memory in multiprocess is *hard*, because not only\nmemory space needs to be preallocated, but it also needs to be attached\nin each process to allow other processes to access the page table. The\nattach API call may or may not succeed, depending on memory layout, for\nreasons similar to other multiprocess failures. This is treated as a\n\"known issue\" for this release.\n\nRFC -> v1 changes:\n- Removed the \"named heaps\" API, allocate using fake socket ID instead\n- Added multiprocess support\n- Everything is now thread-safe\n- Numerous bugfixes and API improvements\n\nAnatoly Burakov (16):\n  mem: add length to memseg list\n  mem: allow memseg lists to be marked as external\n  malloc: index heaps using heap ID rather than NUMA node\n  mem: do not check for invalid socket ID\n  flow_classify: do not check for invalid socket ID\n  pipeline: do not check for invalid socket ID\n  sched: do not check for invalid socket ID\n  malloc: add name to malloc heaps\n  malloc: add function to query socket ID of named heap\n  malloc: allow creating malloc heaps\n  malloc: allow destroying heaps\n  malloc: allow adding memory to named heaps\n  malloc: allow removing memory from named heaps\n  malloc: allow attaching to external memory chunks\n  malloc: allow detaching from external memory\n  test: add unit tests for external memory support\n\n config/common_base                            |   1 +\n config/rte_config.h                           |   1 +\n drivers/bus/fslmc/fslmc_vfio.c                |   7 +-\n drivers/bus/pci/linux/pci.c                   |   2 +-\n drivers/net/mlx4/mlx4_mr.c                    |   3 +\n drivers/net/mlx5/mlx5.c                       |   5 +-\n drivers/net/mlx5/mlx5_mr.c                    |   3 +\n drivers/net/virtio/virtio_user/vhost_kernel.c |   5 +-\n lib/librte_eal/bsdapp/eal/eal.c               |   3 +\n lib/librte_eal/bsdapp/eal/eal_memory.c        |   9 +-\n lib/librte_eal/common/eal_common_memory.c     |   9 +-\n lib/librte_eal/common/eal_common_memzone.c    |   8 +-\n .../common/include/rte_eal_memconfig.h        |   6 +-\n lib/librte_eal/common/include/rte_malloc.h    | 181 +++++++++\n .../common/include/rte_malloc_heap.h          |   3 +\n lib/librte_eal/common/include/rte_memory.h    |   9 +\n lib/librte_eal/common/malloc_heap.c           | 287 +++++++++++--\n lib/librte_eal/common/malloc_heap.h           |  17 +\n lib/librte_eal/common/rte_malloc.c            | 383 ++++++++++++++++-\n lib/librte_eal/linuxapp/eal/eal.c             |   3 +\n lib/librte_eal/linuxapp/eal/eal_memalloc.c    |  12 +-\n lib/librte_eal/linuxapp/eal/eal_memory.c      |   4 +-\n lib/librte_eal/linuxapp/eal/eal_vfio.c        |  17 +-\n lib/librte_eal/            |   7 +\n lib/librte_flow_classify/rte_flow_classify.c  |   3 +-\n lib/librte_mempool/rte_mempool.c              |  31 +-\n lib/librte_pipeline/rte_pipeline.c            |   3 +-\n lib/librte_sched/rte_sched.c                  |   2 +-\n test/test/Makefile                            |   1 +\n test/test/                    |  14 +-\n test/test/                         |   1 +\n test/test/test_external_mem.c                 | 384 ++++++++++++++++++\n test/test/test_malloc.c                       |   3 +\n test/test/test_memzone.c                      |   3 +\n 34 files changed, 1346 insertions(+), 84 deletions(-)\n create mode 100644 test/test/test_external_mem.c"