[dpdk-dev] [PATCH v4] KNI: use a memzone pool for KNI alloc/release

[Marc Sune <marc.sune@bisdn.de>]

This patch implements the KNI memzone pool in order to prevent
memzone exhaustion when allocating/deallocating KNI interfaces.

It adds a new API call, rte_kni_init(max_kni_ifaces) that shall
be called before any call to rte_kni_alloc() if KNI is used.

v2: Moved KNI fd opening to rte_kni_init(). Revised style.
v3: Adapted kni examples/tests to rte_kni_init().
v4: Improved example integration. Fixed kni_memzone_pool_alloc/release() bug.

Signed-off-by: Marc Sune <marc.sune@bisdn.de>
---
 app/test/test_kni.c      |    5 +-
 examples/kni/main.c      |   22 ++++
 lib/librte_kni/rte_kni.c |  317 +++++++++++++++++++++++++++++++++++++---------
 lib/librte_kni/rte_kni.h |   18 +++
 4 files changed, 302 insertions(+), 60 deletions(-)

diff --git a/app/test/test_kni.c b/app/test/test_kni.c
index 1081131..608901d 100644
--- a/app/test/test_kni.c
+++ b/app/test/test_kni.c
@@ -58,7 +58,7 @@
 
 #define IFCONFIG      "/sbin/ifconfig "
 #define TEST_KNI_PORT "test_kni_port"
-
+#define KNI_TEST_MAX_PORTS 4
 /* The threshold number of mbufs to be transmitted or received. */
 #define KNI_NUM_MBUF_THRESHOLD 100
 static int kni_pkt_mtu = 0;
@@ -498,6 +498,9 @@ test_kni(void)
 	struct rte_eth_dev_info info;
 	struct rte_kni_ops ops;
 
+	/* Initialize KNI subsytem */
+	rte_kni_init(KNI_TEST_MAX_PORTS);
+
 	if (test_kni_allocate_lcores() < 0) {
 		printf("No enough lcores for kni processing\n");
 		return -1;
diff --git a/examples/kni/main.c b/examples/kni/main.c
index 69d1ef2..acccd64 100644
--- a/examples/kni/main.c
+++ b/examples/kni/main.c
@@ -616,6 +616,25 @@ parse_args(int argc, char **argv)
 	return ret;
 }
 
+/* Initialize KNI subsystem */
+static void
+init_kni(void)
+{
+	unsigned int num_of_kni_ports = 0, i;
+	struct kni_port_params **params = kni_port_params_array;
+
+	/* Calculate the maximum number of KNI interfaces that will be used */
+	for (i = 0; i < RTE_MAX_ETHPORTS; i++) {
+		if (kni_port_params_array[i]) {
+			num_of_kni_ports += (params[i]->nb_lcore_k ?
+				params[i]->nb_lcore_k : 1);
+		}
+	}
+	
+	/* Invoke rte KNI init to preallocate the ports */	
+	rte_kni_init(num_of_kni_ports);
+}
+
 /* Initialise a single port on an Ethernet device */
 static void
 init_port(uint8_t port)
@@ -901,6 +920,9 @@ main(int argc, char** argv)
 		if (kni_port_params_array[i] && i >= nb_sys_ports)
 			rte_exit(EXIT_FAILURE, "Configured invalid "
 						"port ID %u\n", i);
+	
+	/* Initialize KNI subsystem */
+	init_kni();
 
 	/* Initialise each port */
 	for (port = 0; port < nb_sys_ports; port++) {
diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
index 76feef4..4c7f099 100644
--- a/lib/librte_kni/rte_kni.c
+++ b/lib/librte_kni/rte_kni.c
@@ -40,6 +40,7 @@
 #include <unistd.h>
 #include <sys/ioctl.h>
 
+#include <rte_spinlock.h>
 #include <rte_string_fns.h>
 #include <rte_ethdev.h>
 #include <rte_malloc.h>
@@ -58,7 +59,7 @@
 
 #define KNI_REQUEST_MBUF_NUM_MAX      32
 
-#define KNI_MZ_CHECK(mz) do { if (mz) goto fail; } while (0)
+#define KNI_MEM_CHECK(cond) do { if (cond) goto kni_fail; } while (0)
 
 /**
  * KNI context
@@ -66,6 +67,7 @@
 struct rte_kni {
 	char name[RTE_KNI_NAMESIZE];        /**< KNI interface name */
 	uint16_t group_id;                  /**< Group ID of KNI devices */
+	uint32_t slot_id;                   /**< KNI pool slot ID */
 	struct rte_mempool *pktmbuf_pool;   /**< pkt mbuf mempool */
 	unsigned mbuf_size;                 /**< mbuf size */
 
@@ -88,10 +90,48 @@ enum kni_ops_status {
 	KNI_REQ_REGISTERED,
 };
 
+/**
+ * KNI memzone pool slot
+ */
+struct rte_kni_memzone_slot{
+	uint32_t id;
+	uint8_t in_use : 1;                    /**< slot in use */
+
+	/* Memzones */
+	const struct rte_memzone *m_ctx;       /**< KNI ctx */
+	const struct rte_memzone *m_tx_q;      /**< TX queue */
+	const struct rte_memzone *m_rx_q;      /**< RX queue */
+	const struct rte_memzone *m_alloc_q;   /**< Allocated mbufs queue */
+	const struct rte_memzone *m_free_q;    /**< To be freed mbufs queue */
+	const struct rte_memzone *m_req_q;     /**< Request queue */
+	const struct rte_memzone *m_resp_q;    /**< Response queue */
+	const struct rte_memzone *m_sync_addr;         
+	
+	/* Free linked list */
+	struct rte_kni_memzone_slot *next;     /**< Next slot link.list */
+};
+
+/**
+ * KNI memzone pool
+ */
+struct rte_kni_memzone_pool{
+	uint8_t initialized : 1;            /**< Global KNI pool init flag */
+ 
+	uint32_t max_ifaces;                /**< Max. num of KNI ifaces */
+	struct rte_kni_memzone_slot *slots;        /**< Pool slots */
+	rte_spinlock_t mutex;               /**< alloc/relase mutex */
+
+	/* Free memzone slots linked-list */
+	struct rte_kni_memzone_slot *free;         /**< First empty slot */
+	struct rte_kni_memzone_slot *free_tail;    /**< Last empty slot */
+};
+
+
 static void kni_free_mbufs(struct rte_kni *kni);
 static void kni_allocate_mbufs(struct rte_kni *kni);
 
 static volatile int kni_fd = -1;
+static struct rte_kni_memzone_pool kni_memzone_pool = {0};
 
 static const struct rte_memzone *
 kni_memzone_reserve(const char *name, size_t len, int socket_id,
@@ -105,6 +145,163 @@ kni_memzone_reserve(const char *name, size_t len, int socket_id,
 	return mz;
 }
 
+/* Pool mgmt */
+static struct rte_kni_memzone_slot*
+kni_memzone_pool_alloc(void)
+{
+	struct rte_kni_memzone_slot* slot;
+	
+	rte_spinlock_lock(&kni_memzone_pool.mutex);	
+
+	if(!kni_memzone_pool.free) {
+		rte_spinlock_unlock(&kni_memzone_pool.mutex);	
+		return NULL;
+	}
+
+	slot = kni_memzone_pool.free;
+	kni_memzone_pool.free = slot->next;
+	slot->in_use = 1;
+
+	if(!kni_memzone_pool.free)
+		kni_memzone_pool.free_tail = NULL;
+
+	rte_spinlock_unlock(&kni_memzone_pool.mutex);
+
+	return slot;
+}
+
+static void 
+kni_memzone_pool_release(struct rte_kni_memzone_slot* slot)
+{
+	rte_spinlock_lock(&kni_memzone_pool.mutex);	
+
+	if(kni_memzone_pool.free)
+		kni_memzone_pool.free_tail->next = slot;
+	else
+		kni_memzone_pool.free = slot;
+
+	kni_memzone_pool.free_tail = slot;
+	slot->next = NULL;
+	slot->in_use = 0;
+
+	rte_spinlock_unlock(&kni_memzone_pool.mutex);
+}
+
+
+/* Shall be called before any allocation happens */
+void
+rte_kni_init(unsigned int max_kni_ifaces)
+{
+	uint32_t i;
+	struct rte_kni_memzone_slot* it;
+	const struct rte_memzone *mz;
+#define OBJNAMSIZ 32
+	char obj_name[OBJNAMSIZ];
+	char mz_name[RTE_MEMZONE_NAMESIZE];
+
+	if(max_kni_ifaces == 0) {
+		RTE_LOG(ERR, KNI, "Invalid number of max_kni_ifaces %d\n",
+							max_kni_ifaces);
+		rte_panic("Unable to initialize KNI\n");
+	}
+
+	/* Check FD and open */
+	if (kni_fd < 0) {
+		kni_fd = open("/dev/" KNI_DEVICE, O_RDWR);
+		if (kni_fd < 0) {
+			rte_panic("Can not open /dev/%s\n", KNI_DEVICE);
+		}
+	}
+
+	/* Allocate slot objects */
+	kni_memzone_pool.slots = (struct rte_kni_memzone_slot*)rte_malloc(NULL,
+					sizeof(struct rte_kni_memzone_slot) *
+					max_kni_ifaces,
+					0);
+	KNI_MEM_CHECK(kni_memzone_pool.slots == NULL);
+
+	/* Initialize general pool variables */
+	kni_memzone_pool.initialized = 1;
+	kni_memzone_pool.max_ifaces = max_kni_ifaces;
+	kni_memzone_pool.free = &kni_memzone_pool.slots[0];
+
+	/* Pre-allocate all memzones of all the slots; panic on error */
+	for(i=0; i<max_kni_ifaces; i++) {
+
+		/* Recover current slot */
+		it = &kni_memzone_pool.slots[i];
+		it->id = i;
+	
+		/* Allocate KNI context */
+		snprintf(mz_name, RTE_MEMZONE_NAMESIZE, "KNI_INFO_%d", i);
+		mz = kni_memzone_reserve(mz_name, sizeof(struct rte_kni),
+					SOCKET_ID_ANY, 0);
+		KNI_MEM_CHECK(mz == NULL);
+		it->m_ctx = mz;
+			
+		/* TX RING */
+		snprintf(obj_name, OBJNAMSIZ, "kni_tx_%d", i);
+		mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, 
+							SOCKET_ID_ANY, 0);
+		KNI_MEM_CHECK(mz == NULL);
+		it->m_tx_q = mz;
+
+		/* RX RING */
+		snprintf(obj_name, OBJNAMSIZ, "kni_rx_%d", i);
+		mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, 
+							SOCKET_ID_ANY, 0);
+		KNI_MEM_CHECK(mz == NULL);
+		it->m_rx_q = mz;
+
+		/* ALLOC RING */
+		snprintf(obj_name, OBJNAMSIZ, "kni_alloc_%d", i);
+		mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE,
+							SOCKET_ID_ANY, 0);
+		KNI_MEM_CHECK(mz == NULL);
+		it->m_alloc_q = mz;
+
+		/* FREE RING */
+		snprintf(obj_name, OBJNAMSIZ, "kni_free_%d", i);
+		mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, 
+							SOCKET_ID_ANY, 0);
+		KNI_MEM_CHECK(mz == NULL);
+		it->m_free_q = mz;
+
+		/* Request RING */
+		snprintf(obj_name, OBJNAMSIZ, "kni_req_%d", i);
+		mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, 
+							SOCKET_ID_ANY, 0);
+		KNI_MEM_CHECK(mz == NULL);
+		it->m_req_q = mz;
+
+		/* Response RING */
+		snprintf(obj_name, OBJNAMSIZ, "kni_resp_%d", i);
+		mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, 
+							SOCKET_ID_ANY, 0);
+		KNI_MEM_CHECK(mz == NULL);
+		it->m_resp_q = mz;
+
+		/* Req/Resp sync mem area */
+		snprintf(obj_name, OBJNAMSIZ, "kni_sync_%d", i);
+		mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, 
+							SOCKET_ID_ANY, 0);
+		KNI_MEM_CHECK(mz == NULL);
+		it->m_sync_addr = mz;
+
+		if(i+1 == max_kni_ifaces) {
+			it->next = NULL;
+			kni_memzone_pool.free_tail = it;
+		}else
+			it->next = &kni_memzone_pool.slots[i+1];
+	}
+	
+	return;
+
+kni_fail:
+	rte_panic("Unable to allocate memory for max_kni_ifaces:%d."
+		"increase the amount of hugepages memory\n", max_kni_ifaces);
+}
+
 /* It is deprecated and just for backward compatibility */
 struct rte_kni *
 rte_kni_create(uint8_t port_id,
@@ -140,34 +337,37 @@ rte_kni_alloc(struct rte_mempool *pktmbuf_pool,
 	struct rte_kni_device_info dev_info;
 	struct rte_kni *ctx;
 	char intf_name[RTE_KNI_NAMESIZE];
-#define OBJNAMSIZ 32
-	char obj_name[OBJNAMSIZ];
 	char mz_name[RTE_MEMZONE_NAMESIZE];
 	const struct rte_memzone *mz;
+	struct rte_kni_memzone_slot* slot=NULL;
 
 	if (!pktmbuf_pool || !conf || !conf->name[0])
 		return NULL;
 
-	/* Check FD and open once */
-	if (kni_fd < 0) {
-		kni_fd = open("/dev/" KNI_DEVICE, O_RDWR);
-		if (kni_fd < 0) {
-			RTE_LOG(ERR, KNI, "Can not open /dev/%s\n",
-							KNI_DEVICE);
-			return NULL;
-		}
+	/* Check if KNI subsystem has been initialized */
+	if (kni_memzone_pool.initialized != 1) {
+		RTE_LOG(ERR, KNI, "KNI subsystem has not been initialized. "
+				"Invoke rte_kni_init() first\n");
+		return NULL;
 	}
 
+	/* Get an available slot from the pool */
+	slot = kni_memzone_pool_alloc();
+	if(!slot) {
+		RTE_LOG(ERR, KNI, "Cannot allocate more KNI interfaces; "
+			"increase the number of max_kni_ifaces(current %d) or "
+			"release unusued ones.\n", 
+			kni_memzone_pool.max_ifaces);
+		return NULL;
+	}
+	
+	/* Recover ctx */
+	ctx = slot->m_ctx->addr;
 	snprintf(intf_name, RTE_KNI_NAMESIZE, "%s", conf->name);
-	snprintf(mz_name, RTE_MEMZONE_NAMESIZE, "KNI_INFO_%s", intf_name);
-	mz = kni_memzone_reserve(mz_name, sizeof(struct rte_kni),
-				SOCKET_ID_ANY, 0);
-	KNI_MZ_CHECK(mz == NULL);
-	ctx = mz->addr;
 
 	if (ctx->in_use) {
 		RTE_LOG(ERR, KNI, "KNI %s is in use\n", ctx->name);
-		goto fail;
+		return NULL;
 	}
 	memset(ctx, 0, sizeof(struct rte_kni));
 	if (ops)
@@ -190,83 +390,72 @@ rte_kni_alloc(struct rte_mempool *pktmbuf_pool,
 	RTE_LOG(INFO, KNI, "pci: %02x:%02x:%02x \t %02x:%02x\n",
 		dev_info.bus, dev_info.devid, dev_info.function,
 			dev_info.vendor_id, dev_info.device_id);
-
 	/* TX RING */
-	snprintf(obj_name, OBJNAMSIZ, "kni_tx_%s", intf_name);
-	mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, SOCKET_ID_ANY, 0);
-	KNI_MZ_CHECK(mz == NULL);
+	mz = slot->m_tx_q;
 	ctx->tx_q = mz->addr;
 	kni_fifo_init(ctx->tx_q, KNI_FIFO_COUNT_MAX);
 	dev_info.tx_phys = mz->phys_addr;
 
 	/* RX RING */
-	snprintf(obj_name, OBJNAMSIZ, "kni_rx_%s", intf_name);
-	mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, SOCKET_ID_ANY, 0);
-	KNI_MZ_CHECK(mz == NULL);
+	mz = slot->m_rx_q;
 	ctx->rx_q = mz->addr;
 	kni_fifo_init(ctx->rx_q, KNI_FIFO_COUNT_MAX);
 	dev_info.rx_phys = mz->phys_addr;
 
 	/* ALLOC RING */
-	snprintf(obj_name, OBJNAMSIZ, "kni_alloc_%s", intf_name);
-	mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, SOCKET_ID_ANY, 0);
-	KNI_MZ_CHECK(mz == NULL);
+	mz = slot->m_alloc_q;
 	ctx->alloc_q = mz->addr;
 	kni_fifo_init(ctx->alloc_q, KNI_FIFO_COUNT_MAX);
 	dev_info.alloc_phys = mz->phys_addr;
 
 	/* FREE RING */
-	snprintf(obj_name, OBJNAMSIZ, "kni_free_%s", intf_name);
-	mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, SOCKET_ID_ANY, 0);
-	KNI_MZ_CHECK(mz == NULL);
+	mz = slot->m_free_q;
 	ctx->free_q = mz->addr;
 	kni_fifo_init(ctx->free_q, KNI_FIFO_COUNT_MAX);
 	dev_info.free_phys = mz->phys_addr;
 
 	/* Request RING */
-	snprintf(obj_name, OBJNAMSIZ, "kni_req_%s", intf_name);
-	mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, SOCKET_ID_ANY, 0);
-	KNI_MZ_CHECK(mz == NULL);
+	mz = slot->m_req_q;
 	ctx->req_q = mz->addr;
 	kni_fifo_init(ctx->req_q, KNI_FIFO_COUNT_MAX);
 	dev_info.req_phys = mz->phys_addr;
 
 	/* Response RING */
-	snprintf(obj_name, OBJNAMSIZ, "kni_resp_%s", intf_name);
-	mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, SOCKET_ID_ANY, 0);
-	KNI_MZ_CHECK(mz == NULL);
+	mz = slot->m_resp_q;
 	ctx->resp_q = mz->addr;
 	kni_fifo_init(ctx->resp_q, KNI_FIFO_COUNT_MAX);
 	dev_info.resp_phys = mz->phys_addr;
 
 	/* Req/Resp sync mem area */
-	snprintf(obj_name, OBJNAMSIZ, "kni_sync_%s", intf_name);
-	mz = kni_memzone_reserve(obj_name, KNI_FIFO_SIZE, SOCKET_ID_ANY, 0);
-	KNI_MZ_CHECK(mz == NULL);
+	mz = slot->m_sync_addr; 
 	ctx->sync_addr = mz->addr;
 	dev_info.sync_va = mz->addr;
 	dev_info.sync_phys = mz->phys_addr;
 
+
 	/* MBUF mempool */
 	snprintf(mz_name, sizeof(mz_name), RTE_MEMPOOL_OBJ_NAME,
 		pktmbuf_pool->name);
 	mz = rte_memzone_lookup(mz_name);
-	KNI_MZ_CHECK(mz == NULL);
+	KNI_MEM_CHECK(mz == NULL);
 	dev_info.mbuf_va = mz->addr;
 	dev_info.mbuf_phys = mz->phys_addr;
 	ctx->pktmbuf_pool = pktmbuf_pool;
 	ctx->group_id = conf->group_id;
+	ctx->slot_id = slot->id;
 	ctx->mbuf_size = conf->mbuf_size;
 
 	ret = ioctl(kni_fd, RTE_KNI_IOCTL_CREATE, &dev_info);
-	KNI_MZ_CHECK(ret < 0);
+	KNI_MEM_CHECK(ret < 0);
 
 	ctx->in_use = 1;
 
 	return ctx;
 
-fail:
-
+kni_fail:
+	if(slot)
+		kni_memzone_pool_release(&kni_memzone_pool.slots[slot->id]);
+			
 	return NULL;
 }
 
@@ -287,6 +476,7 @@ int
 rte_kni_release(struct rte_kni *kni)
 {
 	struct rte_kni_device_info dev_info;
+	uint32_t slot_id;
 
 	if (!kni || !kni->in_use)
 		return -1;
@@ -302,8 +492,19 @@ rte_kni_release(struct rte_kni *kni)
 	kni_free_fifo(kni->rx_q);
 	kni_free_fifo(kni->alloc_q);
 	kni_free_fifo(kni->free_q);
+
+	slot_id = kni->slot_id;		
+
+	/* Memset the KNI struct */
 	memset(kni, 0, sizeof(struct rte_kni));
 
+	/* Release memzone */
+	if(slot_id > kni_memzone_pool.max_ifaces) {
+		rte_panic("KNI pool: corrupted slot ID: %d, max: %d\n", 
+			slot_id, kni_memzone_pool.max_ifaces);
+	}
+	kni_memzone_pool_release(&kni_memzone_pool.slots[slot_id]);
+
 	return 0;
 }
 
@@ -437,23 +638,21 @@ rte_kni_get_port_id(struct rte_kni *kni)
 struct rte_kni *
 rte_kni_get(const char *name)
 {
-	struct rte_kni *kni;
-	const struct rte_memzone *mz;
-	char mz_name[RTE_MEMZONE_NAMESIZE];
-
-	if (!name || !name[0])
-		return NULL;
-
-	snprintf(mz_name, RTE_MEMZONE_NAMESIZE, "KNI_INFO_%s", name);
-	mz = rte_memzone_lookup(mz_name);
-	if (!mz)
-		return NULL;
-
-	kni = mz->addr;
-	if (!kni->in_use)
-		return NULL;
+	uint32_t i;
+	struct rte_kni_memzone_slot* it;
+	struct rte_kni* kni;
+
+	/* Note: could be improved perf-wise if necessary */
+	for(i=0; i<kni_memzone_pool.max_ifaces; i++) {
+		it = &kni_memzone_pool.slots[i];
+		if(it->in_use == 0)
+			continue;
+		kni = it->m_ctx->addr;
+		if(strncmp(kni->name, name, RTE_KNI_NAMESIZE) == 0)
+			return kni;
+	}
 
-	return kni;
+	return NULL;
 }
 
 /*
diff --git a/lib/librte_kni/rte_kni.h b/lib/librte_kni/rte_kni.h
index 1a0b004..0159a1d 100644
--- a/lib/librte_kni/rte_kni.h
+++ b/lib/librte_kni/rte_kni.h
@@ -90,11 +90,27 @@ struct rte_kni_conf {
 };
 
 /**
+ * Initialize and preallocate KNI subsystem
+ *
+ * This function is to be executed on the MASTER lcore only, after EAL 
+ * initialization and before any KNI interface is attempted to be
+ * allocated
+ * 
+ * @param max_kni_ifaces 
+ *  The maximum number of KNI interfaces that can coexist concurrently
+ */
+extern void rte_kni_init(unsigned int max_kni_ifaces);
+
+
+/**
  * Allocate KNI interface according to the port id, mbuf size, mbuf pool,
  * configurations and callbacks for kernel requests.The KNI interface created
  * in the kernel space is the net interface the traditional Linux application
  * talking to.
  *
+ * The rte_kni_alloc shall not be called before rte_kni_init() has been
+ * called. rte_kni_alloc is thread safe. 
+ *
  * @param pktmbuf_pool
  *  The mempool for allocting mbufs for packets.
  * @param conf
@@ -138,6 +154,8 @@ extern struct rte_kni *rte_kni_create(uint8_t port_id,
  * Release KNI interface according to the context. It will also release the
  * paired KNI interface in kernel space. All processing on the specific KNI
  * context need to be stopped before calling this interface.
+ * 
+ * rte_kni_release is thread safe.
  *
  * @param kni
  *  The pointer to the context of an existent KNI interface.
-- 
1.7.10.4