fhi_72: allow to provide dpdk_mem_size to xran

xran has a mechanism to request DPDK to allocate a configurable amount
of bytes for huge pages. We set it to 0 until now; expose this variable
through configuration, and provide a meaningful default 8192 MiB.
Provide documentation.

doc/ORAN_FHI7.2_Tutorial.md

@@ -783,6 +783,12 @@ Edit the sample OAI gNB configuration file and check following parameters:
   * `ru_addr`: RU C- and U-plane MAC-addresses (format `UU:VV:WW:XX:YY:ZZ`,
     hexadecimal numbers)
   * `mtu`: Maximum Transmission Unit for the RU, specified by RU vendor
+  * `dpdk_mem_size`: the huge page size that should be pre-allocated by DPDK
+    _for NUMA node 0_; by default, this is 8192 MiB (corresponding to 8 huge
+    pages à 1024 MiB each, see above). In the current implementation, you
+    cannot preallocate memory on NUMA nodes other than 0; in this case, set
+    this to 0 (no pre-allocation) and so that DPDK will allocate it on-demand
+    on the right NUMA node.
   * `fh_config`: parameters that need to match RU parameters
     * timing parameters (starting with `T`) depend on the RU: `Tadv_cp_dl` is a
       single number, the rest pairs of numbers `(x, y)` specifying minimum and

radio/fhi_72/oran-config.c

@@ -498,7 +498,7 @@ static bool set_fh_io_cfg(struct xran_io_cfg *io_cfg, const paramdef_t *fhip, in
   //io_cfg->bbdev_dev = NULL;
   io_cfg->bbdev_mode = XRAN_BBDEV_NOT_USED; // none
   io_cfg->dpdkIoVaMode = 0; /* IOVA mode */
-  io_cfg->dpdkMemorySize = 0; /* DPDK memory size */
+  io_cfg->dpdkMemorySize = *gpd(fhip, nump, ORAN_CONFIG_DPDK_MEM_SIZE)->uptr;
   io_cfg->core = *gpd(fhip, nump, ORAN_CONFIG_IO_CORE)->iptr;
   io_cfg->system_core = *gpd(fhip, nump, ORAN_CONFIG_SYSTEM_CORE)->iptr;
   io_cfg->pkt_proc_core = get_u64_mask(gpd(fhip, nump, ORAN_CONFIG_WORKER_CORES));

radio/fhi_72/oran-params.h

@@ -37,6 +37,7 @@
 #define ORAN_CONFIG_FILE_PREFIX "file_prefix"
 #define ORAN_CONFIG_NETHPERPORT "eth_lines"
 #define ORAN_CONFIG_NETHSPEED "eth_speed"
+#define ORAN_CONFIG_DPDK_MEM_SIZE "dpdk_mem_size"
 
 // clang-format off
 // TODO: PCI addr check
@@ -52,6 +53,7 @@
   {ORAN_CONFIG_FILE_PREFIX,     "DPDK file-prefix\n",                       0,                   .strptr=NULL,     .defstrval="wls_0",  TYPE_STRING,     0}, \
   {ORAN_CONFIG_NETHPERPORT,     "number of links per port\n",               0,                   .uptr=NULL,       .defuintval=1,       TYPE_UINT,       0}, \
   {ORAN_CONFIG_NETHSPEED,       "ethernet speed link\n",                    0,                   .uptr=NULL,       .defuintval=10,      TYPE_UINT,       0}, \
+  {ORAN_CONFIG_DPDK_MEM_SIZE,   "DPDK huge page pre-allocation in MiB\n",   0,                   .uptr=NULL,       .defuintval=8192,    TYPE_UINT,       0}, \
 }
 // clang-format on