eal: add legacy memory option

This adds a "--legacy-mem" command-line switch. It will be used to
go back to the old memory behavior, one where we can't dynamically
allocate/free memory (the downside), but one where the user can
get physically contiguous memory, like before (the upside).

For now, nothing but the legacy behavior exists, non-legacy
memory init sequence will be added later. For FreeBSD, non-legacy
memory init will never be enabled, while for Linux, it is
disabled in this patch to avoid breaking bisect, but will be
enabled once non-legacy mode will be fully operational.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Tested-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>
Tested-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Tested-by: Gowrishankar Muthukrishnan <gowrishankar.m@linux.vnet.ibm.com>

lib/librte_eal/bsdapp/eal/eal.c

@@ -534,6 +534,9 @@ rte_eal_init(int argc, char **argv)
 		return -1;
 	}
 
+	/* FreeBSD always uses legacy memory model */
+	internal_config.legacy_mem = true;
+
 	if (eal_plugins_init() < 0) {
 		rte_eal_init_alert("Cannot init plugins\n");
 		rte_errno = EINVAL;

lib/librte_eal/common/eal_common_options.c

@@ -73,6 +73,7 @@ eal_long_options[] = {
 	{OPT_VDEV,              1, NULL, OPT_VDEV_NUM             },
 	{OPT_VFIO_INTR,         1, NULL, OPT_VFIO_INTR_NUM        },
 	{OPT_VMWARE_TSC_MAP,    0, NULL, OPT_VMWARE_TSC_MAP_NUM   },
+	{OPT_LEGACY_MEM,        0, NULL, OPT_LEGACY_MEM_NUM       },
 	{0,                     0, NULL, 0                        }
 };
 
@@ -1113,6 +1114,8 @@ eal_parse_common_option(int opt, const char *optarg,
 
 	case OPT_NO_HUGE_NUM:
 		conf->no_hugetlbfs = 1;
+		/* no-huge is legacy mem */
+		conf->legacy_mem = 1;
 		break;
 
 	case OPT_NO_PCI_NUM:
@@ -1184,6 +1187,9 @@ eal_parse_common_option(int opt, const char *optarg,
 
 		core_parsed = LCORE_OPT_MAP;
 		break;
+	case OPT_LEGACY_MEM_NUM:
+		conf->legacy_mem = 1;
+		break;
 
 	/* don't know what to do, leave this to caller */
 	default:

lib/librte_eal/common/eal_internal_cfg.h

@@ -47,6 +47,10 @@ struct internal_config {
 	volatile unsigned force_sockets;
 	volatile uint64_t socket_mem[RTE_MAX_NUMA_NODES]; /**< amount of memory per socket */
 	uintptr_t base_virtaddr;          /**< base address to try and reserve memory from */
+	volatile unsigned legacy_mem;
+	/**< true to enable legacy memory behavior (no dynamic allocation,
+	 * IOVA-contiguous segments).
+	 */
 	volatile int syslog_facility;	  /**< facility passed to openlog() */
 	/** default interrupt mode for VFIO */
 	volatile enum rte_intr_mode vfio_intr_mode;

lib/librte_eal/common/eal_options.h

@@ -55,6 +55,8 @@ enum {
 	OPT_VFIO_INTR_NUM,
 #define OPT_VMWARE_TSC_MAP    "vmware-tsc-map"
 	OPT_VMWARE_TSC_MAP_NUM,
+#define OPT_LEGACY_MEM    "legacy-mem"
+	OPT_LEGACY_MEM_NUM,
 	OPT_LONG_MAX_NUM
 };
 

lib/librte_eal/linuxapp/eal/eal.c

@@ -348,6 +348,7 @@ eal_usage(const char *prgname)
 	       "  --"OPT_BASE_VIRTADDR"     Base virtual address\n"
 	       "  --"OPT_CREATE_UIO_DEV"    Create /dev/uioX (usually done by hotplug)\n"
 	       "  --"OPT_VFIO_INTR"         Interrupt mode for VFIO (legacy|msi|msix)\n"
+	       "  --"OPT_LEGACY_MEM"        Legacy memory mode (no dynamic allocation, contiguous segments)\n"
 	       "\n");
 	/* Allow the application to print its usage message too if hook is set */
 	if ( rte_application_usage_hook ) {
@@ -767,6 +768,8 @@ rte_eal_init(int argc, char **argv)
 		rte_atomic32_clear(&run_once);
 		return -1;
 	}
+	/* for now, always set legacy mem */
+	internal_config.legacy_mem = 1;
 
 	if (eal_plugins_init() < 0) {
 		rte_eal_init_alert("Cannot init plugins\n");

lib/librte_eal/linuxapp/eal/eal_memory.c

@@ -922,8 +922,8 @@ huge_recover_sigbus(void)
  *  6. unmap the first mapping
  *  7. fill memsegs in configuration with contiguous zones
  */
-int
-rte_eal_hugepage_init(void)
+static int
+eal_legacy_hugepage_init(void)
 {
 	struct rte_mem_config *mcfg;
 	struct hugepage_file *hugepage = NULL, *tmp_hp = NULL;
@@ -1266,8 +1266,8 @@ getFileSize(int fd)
  * configuration and finds the hugepages which form that segment, mapping them
  * in order to form a contiguous block in the virtual memory space
  */
-int
-rte_eal_hugepage_attach(void)
+static int
+eal_legacy_hugepage_attach(void)
 {
 	const struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
 	struct hugepage_file *hp = NULL;
@@ -1402,6 +1402,22 @@ rte_eal_hugepage_attach(void)
 	return -1;
 }
 
+int
+rte_eal_hugepage_init(void)
+{
+	if (internal_config.legacy_mem)
+		return eal_legacy_hugepage_init();
+	return -1;
+}
+
+int
+rte_eal_hugepage_attach(void)
+{
+	if (internal_config.legacy_mem)
+		return eal_legacy_hugepage_attach();
+	return -1;
+}
+
 int
 rte_eal_using_phys_addrs(void)
 {