This is the new design of Memory Region (MR) for mlx PMD, in order to:
- Accommodate the new memory hotplug model.
- Support non-contiguous Mempool.

Signed-off-by: Yongseok Koh <ys...@mellanox.com>
---
 drivers/net/mlx4/mlx4.c      |   26 +
 drivers/net/mlx4/mlx4.h      |   14 +
 drivers/net/mlx4/mlx4_mr.c   | 1165 ++++++++++++++++++++++++++++++++++++++++++
 drivers/net/mlx4/mlx4_mr.h   |  126 +++++
 drivers/net/mlx4/mlx4_rxq.c  |   14 +-
 drivers/net/mlx4/mlx4_rxtx.c |   35 +-
 drivers/net/mlx4/mlx4_rxtx.h |   71 ++-
 drivers/net/mlx4/mlx4_txq.c  |    8 +
 8 files changed, 1428 insertions(+), 31 deletions(-)
 create mode 100644 drivers/net/mlx4/mlx4_mr.h

diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c
index 47451b651..e6c701d13 100644
--- a/drivers/net/mlx4/mlx4.c
+++ b/drivers/net/mlx4/mlx4.c
@@ -44,9 +44,15 @@
 #include "mlx4.h"
 #include "mlx4_glue.h"
 #include "mlx4_flow.h"
+#include "mlx4_mr.h"
 #include "mlx4_rxtx.h"
 #include "mlx4_utils.h"
 
+struct mlx4_dev_list mlx4_mem_event_cb_list =
+       LIST_HEAD_INITIALIZER(mlx4_mem_event_cb_list);
+
+rte_rwlock_t mlx4_mem_event_rwlock = RTE_RWLOCK_INITIALIZER;
+
 /** Configuration structure for device arguments. */
 struct mlx4_conf {
        struct {
@@ -92,6 +98,20 @@ mlx4_dev_configure(struct rte_eth_dev *dev)
        if (ret)
                ERROR("%p: interrupt handler installation failed",
                      (void *)dev);
+       /*
+        * Once the device is added to the list of memory event callback, its
+        * global MR cache table cannot be expanded on the fly because of
+        * deadlock. If it overflows, lookup should be done by searching MR list
+        * linearly, which is slow.
+        */
+       if (mlx4_mr_btree_init(&priv->mr.cache, MLX4_MR_BTREE_CACHE_N * 2,
+                              dev->device->numa_node)) {
+               /* rte_errno is already set. */
+               return -rte_errno;
+       }
+       rte_rwlock_write_lock(&mlx4_mem_event_rwlock);
+       LIST_INSERT_HEAD(&mlx4_mem_event_cb_list, priv, mem_event_cb);
+       rte_rwlock_write_unlock(&mlx4_mem_event_rwlock);
 exit:
        return ret;
 }
@@ -125,6 +145,9 @@ mlx4_dev_start(struct rte_eth_dev *dev)
                      (void *)dev, strerror(-ret));
                goto err;
        }
+#ifndef NDEBUG
+       mlx4_mr_dump_dev(dev);
+#endif
        ret = mlx4_rxq_intr_enable(priv);
        if (ret) {
                ERROR("%p: interrupt handler installation failed",
@@ -200,6 +223,7 @@ mlx4_dev_close(struct rte_eth_dev *dev)
                mlx4_rx_queue_release(dev->data->rx_queues[i]);
        for (i = 0; i != dev->data->nb_tx_queues; ++i)
                mlx4_tx_queue_release(dev->data->tx_queues[i]);
+       mlx4_mr_release(dev);
        if (priv->pd != NULL) {
                assert(priv->ctx != NULL);
                claim_zero(mlx4_glue->dealloc_pd(priv->pd));
@@ -964,6 +988,8 @@ rte_mlx4_pmd_init(void)
        }
        mlx4_glue->fork_init();
        rte_pci_register(&mlx4_driver);
+       rte_mem_event_callback_register("MLX4_MEM_EVENT_CB",
+                                       mlx4_mr_mem_event_cb);
 }
 
 RTE_PMD_EXPORT_NAME(net_mlx4, __COUNTER__);
diff --git a/drivers/net/mlx4/mlx4.h b/drivers/net/mlx4/mlx4.h
index e0e1b5d4c..300cb4d7a 100644
--- a/drivers/net/mlx4/mlx4.h
+++ b/drivers/net/mlx4/mlx4.h
@@ -23,6 +23,9 @@
 #include <rte_ether.h>
 #include <rte_interrupts.h>
 #include <rte_mempool.h>
+#include <rte_rwlock.h>
+
+#include "mlx4_mr.h"
 
 #ifndef IBV_RX_HASH_INNER
 /** This is not necessarily defined by supported RDMA core versions. */
@@ -66,8 +69,12 @@ struct rxq;
 struct txq;
 struct rte_flow;
 
+LIST_HEAD(mlx4_dev_list, priv);
+LIST_HEAD(mlx4_mr_list, mlx4_mr);
+
 /** Private data structure. */
 struct priv {
+       LIST_ENTRY(priv) mem_event_cb; /* Called by memory event callback. */
        struct rte_eth_dev *dev; /**< Ethernet device. */
        struct ibv_context *ctx; /**< Verbs context. */
        struct ibv_device_attr device_attr; /**< Device properties. */
@@ -86,6 +93,13 @@ struct priv {
        uint64_t hw_rss_sup; /**< Supported RSS hash fields (Verbs format). */
        struct rte_intr_handle intr_handle; /**< Port interrupt handle. */
        struct mlx4_drop *drop; /**< Shared resources for drop flow rules. */
+       struct {
+               uint32_t dev_gen; /* Generation number to flush local caches. */
+               rte_rwlock_t rwlock; /* MR Lock. */
+               struct mlx4_mr_btree cache; /* Global MR cache table. */
+               struct mlx4_mr_list mr_list; /* Registered MR list. */
+               struct mlx4_mr_list mr_free_list; /* Freed MR list. */
+       } mr;
        LIST_HEAD(, mlx4_rss) rss; /**< Shared targets for Rx flow rules. */
        LIST_HEAD(, rte_flow) flows; /**< Configured flow rule handles. */
        struct ether_addr mac[MLX4_MAX_MAC_ADDRESSES];
diff --git a/drivers/net/mlx4/mlx4_mr.c b/drivers/net/mlx4/mlx4_mr.c
index 3c87f6849..4812f7109 100644
--- a/drivers/net/mlx4/mlx4_mr.c
+++ b/drivers/net/mlx4/mlx4_mr.c
@@ -30,8 +30,1173 @@
 #include <rte_malloc.h>
 #include <rte_memory.h>
 #include <rte_mempool.h>
+#include <rte_rwlock.h>
 
 #include "mlx4_glue.h"
+#include "mlx4_mr.h"
 #include "mlx4_rxtx.h"
 #include "mlx4_utils.h"
 
+struct mr_find_contig_memsegs_data {
+       uintptr_t addr;
+       uintptr_t start;
+       uintptr_t end;
+       const struct rte_memseg_list *msl;
+};
+
+struct mr_update_mp_data {
+       struct rte_eth_dev *dev;
+       struct mlx4_mr_ctrl *mr_ctrl;
+       int ret;
+};
+
+/**
+ * Expand B-tree table to a given size. Can't be called with holding
+ * memory_hotplug_lock or priv->mr.rwlock due to rte_realloc().
+ *
+ * @param bt
+ *   Pointer to B-tree structure.
+ * @param n
+ *   Number of entries for expansion.
+ *
+ * @return
+ *   0 on success, -1 on failure.
+ */
+static int
+mr_btree_expand(struct mlx4_mr_btree *bt, int n)
+{
+       void *mem;
+       int ret = 0;
+
+       if (n <= bt->size)
+               return ret;
+       /*
+        * Downside of directly using rte_realloc() is that SOCKET_ID_ANY is
+        * used inside if there's no room to expand. Because this is a quite
+        * rare case and a part of very slow path, it is very acceptable.
+        * Initially cache_bh[] will be given practically enough space and once
+        * it is expanded, expansion wouldn't be needed again ever.
+        */
+       mem = rte_realloc(bt->table, n * sizeof(struct mlx4_mr_cache), 0);
+       if (mem == NULL) {
+               /* Not an error, B-tree search will be skipped. */
+               WARN("failed to expand MR B-tree (%p) table", (void *)bt);
+               ret = -1;
+       } else {
+               DEBUG("expanded MR B-tree table (size=%u)", n);
+               bt->table = mem;
+               bt->size = n;
+       }
+       return ret;
+}
+
+/**
+ * Look up LKey from given B-tree lookup table, store the last index and return
+ * searched LKey.
+ *
+ * @param bt
+ *   Pointer to B-tree structure.
+ * @param[out] idx
+ *   Pointer to index. Even on searh failure, returns index where it stops
+ *   searching so that index can be used when inserting a new entry.
+ * @param addr
+ *   Search key.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on no match.
+ */
+static uint32_t
+mr_btree_lookup(struct mlx4_mr_btree *bt, uint16_t *idx, uintptr_t addr)
+{
+       struct mlx4_mr_cache *lkp_tbl;
+       uint16_t n;
+       uint16_t base = 0;
+
+       assert(bt != NULL);
+       lkp_tbl = *bt->table;
+       n = bt->len;
+       /* First entry must be NULL for comparison. */
+       assert(bt->len > 0 || (lkp_tbl[0].start == 0 &&
+                              lkp_tbl[0].lkey == UINT32_MAX));
+       /* Binary search. */
+       do {
+               register uint16_t delta = n >> 1;
+
+               if (addr < lkp_tbl[base + delta].start) {
+                       n = delta;
+               } else {
+                       base += delta;
+                       n -= delta;
+               }
+       } while (n > 1);
+       assert(addr >= lkp_tbl[base].start);
+       *idx = base;
+       if (addr < lkp_tbl[base].end)
+               return lkp_tbl[base].lkey;
+       /* Not found. */
+       return UINT32_MAX;
+}
+
+/**
+ * Insert an entry to B-tree lookup table.
+ *
+ * @param bt
+ *   Pointer to B-tree structure.
+ * @param entry
+ *   Pointer to new entry to insert.
+ *
+ * @return
+ *   0 on success, -1 on failure.
+ */
+static int
+mr_btree_insert(struct mlx4_mr_btree *bt, struct mlx4_mr_cache *entry)
+{
+       struct mlx4_mr_cache *lkp_tbl;
+       uint16_t idx = 0;
+       size_t shift;
+
+       assert(bt != NULL);
+       assert(bt->len <= bt->size);
+       assert(bt->len > 0);
+       lkp_tbl = *bt->table;
+       /* Find out the slot for insertion. */
+       if (mr_btree_lookup(bt, &idx, entry->start) != UINT32_MAX) {
+               DEBUG("abort insertion to B-tree(%p):"
+                     " already exist at idx=%u [0x%lx, 0x%lx) lkey=0x%x",
+                     (void *)bt, idx, entry->start, entry->end, entry->lkey);
+               /* Already exist, return. */
+               return 0;
+       }
+       /* If table is full, return error. */
+       if (unlikely(bt->len == bt->size)) {
+               bt->overflow = 1;
+               return -1;
+       }
+       /* Insert entry. */
+       ++idx;
+       shift = (bt->len - idx) * sizeof(struct mlx4_mr_cache);
+       if (shift)
+               memmove(&lkp_tbl[idx + 1], &lkp_tbl[idx], shift);
+       lkp_tbl[idx] = *entry;
+       bt->len++;
+       DEBUG("inserted B-tree(%p)[%u], [0x%lx, 0x%lx) lkey=0x%x",
+             (void *)bt, idx, entry->start, entry->end, entry->lkey);
+       return 0;
+}
+
+/**
+ * Initialize B-tree and allocate memory for lookup table.
+ *
+ * @param bt
+ *   Pointer to B-tree structure.
+ * @param n
+ *   Number of entries to allocate.
+ * @param socket
+ *   NUMA socket on which memory must be allocated.
+ *
+ * @return
+ *   0 on success, a negative errno value otherwise and rte_errno is set.
+ */
+int
+mlx4_mr_btree_init(struct mlx4_mr_btree *bt, int n, int socket)
+{
+       if (bt == NULL) {
+               rte_errno = EINVAL;
+               return -rte_errno;
+       }
+       memset(bt, 0, sizeof(*bt));
+       bt->table = rte_calloc_socket("B-tree table",
+                                     n, sizeof(struct mlx4_mr_cache),
+                                     0, socket);
+       if (bt->table == NULL) {
+               rte_errno = ENOMEM;
+               ERROR("failed to allocate memory for btree cache on socket %d",
+                     socket);
+               return -rte_errno;
+       }
+       bt->size = n;
+       /* First entry must be NULL for binary search. */
+       (*bt->table)[bt->len++] = (struct mlx4_mr_cache) {
+               .lkey = UINT32_MAX,
+       };
+       DEBUG("initialized B-tree %p with table %p",
+             (void *)bt, (void *)bt->table);
+       return 0;
+}
+
+/**
+ * Free B-tree resources.
+ *
+ * @param bt
+ *   Pointer to B-tree structure.
+ */
+void
+mlx4_mr_btree_free(struct mlx4_mr_btree *bt)
+{
+       if (bt == NULL)
+               return;
+       DEBUG("freeing B-tree %p with table %p", (void *)bt, (void *)bt->table);
+       rte_free(bt->table);
+       memset(bt, 0, sizeof(*bt));
+}
+
+#ifndef NDEBUG
+/**
+ * Dump all the entries in a B-tree
+ *
+ * @param bt
+ *   Pointer to B-tree structure.
+ */
+void
+mlx4_mr_btree_dump(struct mlx4_mr_btree *bt)
+{
+       int idx;
+       struct mlx4_mr_cache *lkp_tbl;
+
+       if (bt == NULL)
+               return;
+       lkp_tbl = *bt->table;
+       for (idx = 0; idx < bt->len; ++idx) {
+               struct mlx4_mr_cache *entry = &lkp_tbl[idx];
+
+               DEBUG("B-tree(%p)[%u], [0x%lx, 0x%lx) lkey=0x%x",
+                     (void *)bt, idx, entry->start, entry->end, entry->lkey);
+       }
+}
+#endif
+
+/**
+ * Find virtually contiguous memory chunk in a given MR.
+ *
+ * @param dev
+ *   Pointer to MR structure.
+ * @param[out] entry
+ *   Pointer to returning MR cache entry. If not found, this will not be
+ *   updated.
+ * @param start_idx
+ *   Start index of the memseg bitmap.
+ *
+ * @return
+ *   Next index to go on lookup.
+ */
+static int
+mr_find_next_chunk(struct mlx4_mr *mr, struct mlx4_mr_cache *entry,
+                  int base_idx)
+{
+       uintptr_t start = 0;
+       uintptr_t end = 0;
+       uint32_t idx = 0;
+
+       for (idx = base_idx; idx < mr->ms_bmp_n; ++idx) {
+               if (rte_bitmap_get(mr->ms_bmp, idx)) {
+                       const struct rte_memseg_list *msl;
+                       const struct rte_memseg *ms;
+
+                       msl = mr->msl;
+                       ms = rte_fbarray_get(&msl->memseg_arr,
+                                            mr->ms_base_idx + idx);
+                       assert(msl->page_sz == ms->hugepage_sz);
+                       if (!start)
+                               start = ms->addr_64;
+                       end = ms->addr_64 + ms->hugepage_sz;
+               } else if (start) {
+                       /* Passed the end of a fragment. */
+                       break;
+               }
+       }
+       if (start) {
+               /* Found one chunk. */
+               entry->start = start;
+               entry->end = end;
+               entry->lkey = rte_cpu_to_be_32(mr->ibv_mr->lkey);
+       }
+       return idx;
+}
+
+/**
+ * Insert a MR to the global B-tree cache. It may fail due to low-on-memory.
+ * Then, this entry will have to be searched by mr_lookup_dev_list() in
+ * mlx4_mr_create() on miss.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param mr
+ *   Pointer to MR to insert.
+ *
+ * @return
+ *   0 on success, -1 on failure.
+ */
+static int
+mr_insert_dev_cache(struct rte_eth_dev *dev, struct mlx4_mr *mr)
+{
+       struct priv *priv = dev->data->dev_private;
+       unsigned int n;
+
+       DEBUG("port %u inserting MR(%p) to global cache",
+             dev->data->port_id, (void *)mr);
+       for (n = 0; n < mr->ms_bmp_n; ) {
+               struct mlx4_mr_cache entry = { 0, };
+
+               /* Find a contiguous chunk and advance the index. */
+               n = mr_find_next_chunk(mr, &entry, n);
+               if (!entry.end)
+                       break;
+               if (mr_btree_insert(&priv->mr.cache, &entry) < 0) {
+                       /*
+                        * Overflowed, but the global table cannot be expanded
+                        * because of deadlock.
+                        */
+                       return -1;
+               }
+       }
+       return 0;
+}
+
+/**
+ * Look up address in the original global MR list.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param[out] entry
+ *   Pointer to returning MR cache entry. If no match, this will not be 
updated.
+ * @param addr
+ *   Search key.
+ *
+ * @return
+ *   Found MR on match, NULL otherwise.
+ */
+static struct mlx4_mr *
+mr_lookup_dev_list(struct rte_eth_dev *dev, struct mlx4_mr_cache *entry,
+                  uintptr_t addr)
+{
+       struct priv *priv = dev->data->dev_private;
+       struct mlx4_mr *mr;
+
+       /* Iterate all the existing MRs. */
+       LIST_FOREACH(mr, &priv->mr.mr_list, mr) {
+               unsigned int n;
+
+               if (mr->ms_n == 0)
+                       continue;
+               for (n = 0; n < mr->ms_bmp_n; ) {
+                       struct mlx4_mr_cache ret = { 0, };
+
+                       n = mr_find_next_chunk(mr, &ret, n);
+                       if (addr >= ret.start && addr < ret.end) {
+                               /* Found. */
+                               *entry = ret;
+                               return mr;
+                       }
+               }
+       }
+       return NULL;
+}
+
+/**
+ * Look up address on device.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param[out] entry
+ *   Pointer to returning MR cache entry. If no match, this will not be 
updated.
+ * @param addr
+ *   Search key.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on failure and rte_errno is set.
+ */
+static uint32_t
+mr_lookup_dev(struct rte_eth_dev *dev, struct mlx4_mr_cache *entry,
+             uintptr_t addr)
+{
+       struct priv *priv = dev->data->dev_private;
+       uint16_t idx;
+       uint32_t lkey = UINT32_MAX;
+       struct mlx4_mr *mr;
+
+       /*
+        * If the global cache has overflowed since it failed to expand the
+        * B-tree table, it can't have all the exisitng MRs. Then, the address
+        * has to be searched by traversing the original MR list instead, which
+        * is very slow path. Otherwise, the global cache is all inclusive.
+        */
+       if (!unlikely(priv->mr.cache.overflow)) {
+               lkey = mr_btree_lookup(&priv->mr.cache, &idx, addr);
+               if (lkey != UINT32_MAX)
+                       *entry = (*priv->mr.cache.table)[idx];
+       } else {
+               /* Falling back to the slowest path. */
+               mr = mr_lookup_dev_list(dev, entry, addr);
+               if (mr != NULL)
+                       lkey = entry->lkey;
+       }
+       assert(lkey == UINT32_MAX || (addr >= entry->start &&
+                                     addr < entry->end));
+       return lkey;
+}
+
+/**
+ * Free MR resources. MR lock must not be held to avoid a deadlock. rte_free()
+ * can raise memory free event and the callback function will spin on the lock.
+ *
+ * @param mr
+ *   Pointer to MR to free.
+ */
+static void
+mr_free(struct mlx4_mr *mr)
+{
+       if (mr == NULL)
+               return;
+       DEBUG("freeing MR(%p):", (void *)mr);
+       if (mr->ibv_mr != NULL)
+               claim_zero(mlx4_glue->dereg_mr(mr->ibv_mr));
+       if (mr->ms_bmp != NULL)
+               rte_bitmap_free(mr->ms_bmp);
+       rte_free(mr);
+}
+
+/**
+ * Free Memory Region (MR).
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param mr
+ *   Pointer to MR to free.
+ */
+void
+mlx4_mr_free(struct rte_eth_dev *dev, struct mlx4_mr *mr)
+{
+       struct priv *priv = dev->data->dev_private;
+
+       /* Detach from the list and free resources later. */
+       rte_rwlock_write_lock(&priv->mr.rwlock);
+       LIST_REMOVE(mr, mr);
+       rte_rwlock_write_unlock(&priv->mr.rwlock);
+       /*
+        * rte_free() inside can't be called with holding the lock. This could
+        * cause deadlock when calling free callback.
+        */
+       mr_free(mr);
+       DEBUG("port %u MR(%p) freed", dev->data->port_id, (void *)mr);
+}
+
+/**
+ * Releass resources of detached MR having no online entry.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ */
+static void
+mlx4_mr_garbage_collect(struct rte_eth_dev *dev)
+{
+       struct priv *priv = dev->data->dev_private;
+       struct mlx4_mr *mr_next;
+       struct mlx4_mr_list free_list = LIST_HEAD_INITIALIZER(free_list);
+
+       /*
+        * MR can't be freed with holding the lock because rte_free() could call
+        * memory free callback function. This will be a deadlock situation.
+        */
+       rte_rwlock_write_lock(&priv->mr.rwlock);
+       /* Detach the whole free list and release it after unlocking. */
+       free_list = priv->mr.mr_free_list;
+       LIST_INIT(&priv->mr.mr_free_list);
+       rte_rwlock_write_unlock(&priv->mr.rwlock);
+       /* Release resources. */
+       mr_next = LIST_FIRST(&free_list);
+       while (mr_next != NULL) {
+               struct mlx4_mr *mr = mr_next;
+
+               mr_next = LIST_NEXT(mr, mr);
+               mr_free(mr);
+       }
+}
+
+/* Called during rte_memseg_contig_walk() by mlx4_mr_create(). */
+static int
+mr_find_contig_memsegs_cb(const struct rte_memseg_list *msl,
+                         const struct rte_memseg *ms, size_t len, void *arg)
+{
+       struct mr_find_contig_memsegs_data *data = arg;
+
+       if (data->addr < ms->addr_64 || data->addr >= ms->addr_64 + len)
+               return 0;
+       /* Found, save it and stop walking. */
+       data->start = ms->addr_64;
+       data->end = ms->addr_64 + len;
+       data->msl = msl;
+       return 1;
+}
+
+/**
+ * Create a new global Memroy Region (MR) for a missing virtual address.
+ * Register entire virtually contiguous memory chunk around the address.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param[out] entry
+ *   Pointer to returning MR cache entry, found in the global cache or newly
+ *   created. If failed to create one, this will not be updated.
+ * @param addr
+ *   Target virtual address to register.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on failure and rte_errno is set.
+ */
+static uint32_t
+mlx4_mr_create(struct rte_eth_dev *dev, struct mlx4_mr_cache *entry,
+              uintptr_t addr)
+{
+       struct priv *priv = dev->data->dev_private;
+       struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+       const struct rte_memseg_list *msl;
+       const struct rte_memseg *ms;
+       struct mlx4_mr *mr = NULL;
+       size_t len;
+       uint32_t ms_n;
+       uint32_t bmp_size;
+       void *bmp_mem;
+       int ms_idx_shift = -1;
+       unsigned int n;
+       struct mr_find_contig_memsegs_data data = {
+               .addr = addr,
+       };
+       struct mr_find_contig_memsegs_data data_re;
+
+       DEBUG("port %u creating a MR using address (%p)",
+             dev->data->port_id, (void *)addr);
+       /*
+        * Release detached MRs if any. This can't be called with holding either
+        * memory_hotplug_lock or priv->mr.rwlock. MRs on the free list have
+        * been detached by the memory free event but it couldn't be released
+        * inside the callback due to deadlock. As a result, releasing resources
+        * is quite opportunistic.
+        */
+       mlx4_mr_garbage_collect(dev);
+       /*
+        * Find out a contiguous virtual address chunk in use, to which the
+        * given address belongs, in order to register maximum range. In the
+        * best case where mempools are not dynamically recreated and
+        * '--socket-mem' is speicified as an EAL option, it is very likely to
+        * have only one MR(LKey) per a socket and per a hugepage-size even
+        * though the system memory is highly fragmented.
+        */
+       if (!rte_memseg_contig_walk(mr_find_contig_memsegs_cb, &data)) {
+               WARN("port %u unable to find virtually contigous"
+                    " chunk for address (%p)."
+                    " rte_memseg_contig_walk() failed.",
+                    dev->data->port_id, (void *)addr);
+               rte_errno = ENXIO;
+               goto err_nolock;
+       }
+alloc_resources:
+       /* Addresses must be page-aligned. */
+       assert(rte_is_aligned((void *)data.start, data.msl->page_sz));
+       assert(rte_is_aligned((void *)data.end, data.msl->page_sz));
+       msl = data.msl;
+       ms = rte_mem_virt2memseg((void *)data.start, msl);
+       len = data.end - data.start;
+       assert(msl->page_sz == ms->hugepage_sz);
+       /* Number of memsegs in the range. */
+       ms_n = len / msl->page_sz;
+       DEBUG("port %u extending %p to [0x%lx, 0x%lx), page_sz=0x%lx, ms_n=%u",
+             dev->data->port_id, (void *)addr,
+             data.start, data.end, msl->page_sz, ms_n);
+       /* Size of memory for bitmap. */
+       bmp_size = rte_bitmap_get_memory_footprint(ms_n);
+       mr = rte_zmalloc_socket(NULL,
+                               RTE_ALIGN_CEIL(sizeof(*mr),
+                                              RTE_CACHE_LINE_SIZE) +
+                               bmp_size,
+                               RTE_CACHE_LINE_SIZE, msl->socket_id);
+       if (mr == NULL) {
+               WARN("port %u unable to allocate memory for a new MR of"
+                    " address (%p).",
+                    dev->data->port_id, (void *)addr);
+               rte_errno = ENOMEM;
+               goto err_nolock;
+       }
+       mr->msl = msl;
+       /*
+        * Save the index of the first memseg and initialize memseg bitmap. To
+        * see if a memseg of ms_idx in the memseg-list is still valid, check:
+        *      rte_bitmap_get(mr->bmp, ms_idx - mr->ms_base_idx)
+        */
+       mr->ms_base_idx = rte_fbarray_find_idx(&msl->memseg_arr, ms);
+       bmp_mem = RTE_PTR_ALIGN_CEIL(mr + 1, RTE_CACHE_LINE_SIZE);
+       mr->ms_bmp = rte_bitmap_init(ms_n, bmp_mem, bmp_size);
+       if (mr->ms_bmp == NULL) {
+               WARN("port %u unable to initialize bitamp for a new MR of"
+                    " address (%p).",
+                    dev->data->port_id, (void *)addr);
+               rte_errno = EINVAL;
+               goto err_nolock;
+       }
+       /*
+        * Should recheck whether the extended contiguous chunk is still valid.
+        * Because memory_hotplug_lock can't be held if there's any memory
+        * related calls in a critical path, resource allocation above can't be
+        * locked. If the memory has been changed at this point, try again with
+        * just single page. If not, go on with the big chunk atomically from
+        * here.
+        */
+       rte_rwlock_read_lock(&mcfg->memory_hotplug_lock);
+       data_re = data;
+       if (len > msl->page_sz &&
+           !rte_memseg_contig_walk(mr_find_contig_memsegs_cb, &data_re)) {
+               WARN("port %u unable to find virtually contigous"
+                    " chunk for address (%p)."
+                    " rte_memseg_contig_walk() failed.",
+                    dev->data->port_id, (void *)addr);
+               rte_errno = ENXIO;
+               goto err_memlock;
+       }
+       if (data.start != data_re.start || data.end != data_re.end) {
+               /*
+                * The extended contiguous chunk has been changed. Try again
+                * with single memseg instead.
+                */
+               data.start = RTE_ALIGN_FLOOR(addr, msl->page_sz);
+               data.end = data.start + msl->page_sz;
+               rte_rwlock_read_unlock(&mcfg->memory_hotplug_lock);
+               mr_free(mr);
+               goto alloc_resources;
+       }
+       assert(data.msl == data_re.msl);
+       rte_rwlock_write_lock(&priv->mr.rwlock);
+       /*
+        * Check the address is really missing. If other thread already created
+        * one or it is not found due to overflow, abort and return.
+        */
+       if (mr_lookup_dev(dev, entry, addr) != UINT32_MAX) {
+               /*
+                * Insert to the global cache table. It may fail due to
+                * low-on-memory. Then, this entry will have to be searched
+                * here again.
+                */
+               mr_btree_insert(&priv->mr.cache, entry);
+               DEBUG("port %u found MR for %p on final lookup, abort",
+                     dev->data->port_id, (void *)addr);
+               rte_rwlock_write_unlock(&priv->mr.rwlock);
+               rte_rwlock_read_unlock(&mcfg->memory_hotplug_lock);
+               /*
+                * Must be unlocked before calling rte_free() because
+                * mlx4_mr_mem_event_free_cb() can be called inside.
+                */
+               mr_free(mr);
+               return entry->lkey;
+       }
+       /*
+        * Trim start and end addresses for verbs MR. Set bits for registering
+        * memsegs but exclude already registered ones. Bitmap can be
+        * fragmented.
+        */
+       for (n = 0; n < ms_n; ++n) {
+               uintptr_t start;
+               struct mlx4_mr_cache ret = { 0, };
+
+               start = data_re.start + n * msl->page_sz;
+               /* Exclude memsegs already registered by other MRs. */
+               if (mr_lookup_dev(dev, &ret, start) == UINT32_MAX) {
+                       /*
+                        * Start from the first unregistered memseg in the
+                        * extended range.
+                        */
+                       if (ms_idx_shift == -1) {
+                               mr->ms_base_idx += n;
+                               data.start = start;
+                               ms_idx_shift = n;
+                       }
+                       data.end = start + msl->page_sz;
+                       rte_bitmap_set(mr->ms_bmp, n - ms_idx_shift);
+                       ++mr->ms_n;
+               }
+       }
+       len = data.end - data.start;
+       mr->ms_bmp_n = len / msl->page_sz;
+       assert(ms_idx_shift + mr->ms_bmp_n <= ms_n);
+       /*
+        * Finally create a verbs MR for the memory chunk. ibv_reg_mr() can be
+        * called with holding the memory lock because it doesn't use
+        * mlx4_alloc_buf_extern() which eventually calls rte_malloc_socket()
+        * through mlx4_alloc_verbs_buf().
+        */
+       mr->ibv_mr = mlx4_glue->reg_mr(priv->pd, (void *)data.start, len,
+                                      IBV_ACCESS_LOCAL_WRITE);
+       if (mr->ibv_mr == NULL) {
+               WARN("port %u fail to create a verbs MR for address (%p)",
+                    dev->data->port_id, (void *)addr);
+               rte_errno = EINVAL;
+               goto err_mrlock;
+       }
+       assert((uintptr_t)mr->ibv_mr->addr == data.start);
+       assert(mr->ibv_mr->length == len);
+       LIST_INSERT_HEAD(&priv->mr.mr_list, mr, mr);
+       DEBUG("port %u MR CREATED (%p) for %p:\n"
+             "  [0x%lx, 0x%lx), lkey=0x%x base_idx=%u ms_n=%u, ms_bmp_n=%u",
+             dev->data->port_id, (void *)mr, (void *)addr,
+             data.start, data.end, rte_cpu_to_be_32(mr->ibv_mr->lkey),
+             mr->ms_base_idx, mr->ms_n, mr->ms_bmp_n);
+       /* Insert to the global cache table. */
+       mr_insert_dev_cache(dev, mr);
+       /* Fill in output data. */
+       mr_lookup_dev(dev, entry, addr);
+       /* Lookup can't fail. */
+       assert(entry->lkey != UINT32_MAX);
+       rte_rwlock_write_unlock(&priv->mr.rwlock);
+       rte_rwlock_read_unlock(&mcfg->memory_hotplug_lock);
+       return entry->lkey;
+err_mrlock:
+       rte_rwlock_write_unlock(&priv->mr.rwlock);
+err_memlock:
+       rte_rwlock_read_unlock(&mcfg->memory_hotplug_lock);
+err_nolock:
+       /*
+        * In case of error, as this can be called in a datapath, a warning
+        * message per an error is preferable instead. Must be unlocked before
+        * calling rte_free() because mlx4_mr_mem_event_free_cb() can be called
+        * inside.
+        */
+       mr_free(mr);
+       return UINT32_MAX;
+}
+
+/**
+ * Rebuild the global B-tree cache of device from the original MR list.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ */
+static void
+mr_rebuild_dev_cache(struct rte_eth_dev *dev)
+{
+       struct priv *priv = dev->data->dev_private;
+       struct mlx4_mr *mr;
+
+       DEBUG("port %u rebuild dev cache[]", dev->data->port_id);
+       /* Flush cache to rebuild. */
+       priv->mr.cache.len = 1;
+       priv->mr.cache.overflow = 0;
+       /* Iterate all the existing MRs. */
+       LIST_FOREACH(mr, &priv->mr.mr_list, mr)
+               if (mr_insert_dev_cache(dev, mr) < 0)
+                       return;
+}
+
+/**
+ * Callback for memory free event. Iterate freed memsegs and check whether it
+ * belongs to an existing MR. If found, clear the bit from bitmap of MR. As a
+ * result, the MR would be fragmented. If it becomes empty, the MR will be 
freed
+ * later by mlx4_mr_garbage_collect().
+ *
+ * The global cache must be rebuilt if there's any change and this event has to
+ * be propagated to dataplane threads to flush the local caches.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param addr
+ *   Address of freed memory.
+ * @param len
+ *   Size of freed memory.
+ */
+static void
+mlx4_mr_mem_event_free_cb(struct rte_eth_dev *dev, const void *addr, size_t 
len)
+{
+       struct priv *priv = dev->data->dev_private;
+       const struct rte_memseg_list *msl;
+       struct mlx4_mr *mr;
+       int ms_n;
+       int i;
+       int rebuild = 0;
+
+       DEBUG("port %u free callback: addr=%p, len=%lu",
+             dev->data->port_id, addr, len);
+       msl = rte_mem_virt2memseg_list(addr);
+       /* addr and len must be page-aligned. */
+       assert((uintptr_t)addr == RTE_ALIGN((uintptr_t)addr, msl->page_sz));
+       assert(len == RTE_ALIGN(len, msl->page_sz));
+       ms_n = len / msl->page_sz;
+       rte_rwlock_write_lock(&priv->mr.rwlock);
+       /* Clear bits of freed memsegs from MR. */
+       for (i = 0; i < ms_n; ++i) {
+               const struct rte_memseg *ms;
+               struct mlx4_mr_cache entry;
+               uintptr_t start;
+               int ms_idx;
+               uint32_t pos;
+
+               /* Find MR having this memseg. */
+               start = (uintptr_t)addr + i * msl->page_sz;
+               mr = mr_lookup_dev_list(dev, &entry, start);
+               if (mr == NULL)
+                       continue;
+               ms = rte_mem_virt2memseg((void *)start, msl);
+               assert(ms != NULL);
+               assert(msl->page_sz == ms->hugepage_sz);
+               ms_idx = rte_fbarray_find_idx(&msl->memseg_arr, ms);
+               pos = ms_idx - mr->ms_base_idx;
+               assert(rte_bitmap_get(mr->ms_bmp, pos));
+               assert(pos < mr->ms_bmp_n);
+               DEBUG("port %u MR(%p): clear bitmap[%u] for addr %p",
+                     dev->data->port_id, (void *)mr, pos, (void *)start);
+               rte_bitmap_clear(mr->ms_bmp, pos);
+               if (--mr->ms_n == 0) {
+                       LIST_REMOVE(mr, mr);
+                       LIST_INSERT_HEAD(&priv->mr.mr_free_list, mr, mr);
+                       DEBUG("port %u remove MR(%p) from list",
+                             dev->data->port_id, (void *)mr);
+               }
+               /*
+                * MR is fragmented or will be freed. the global cache must be
+                * rebuilt.
+                */
+               rebuild = 1;
+       }
+       if (rebuild) {
+               mr_rebuild_dev_cache(dev);
+               /*
+                * Flush local caches by propagating invalidation across cores.
+                * rte_smp_wmb() is enough to synchronize this event. If one of
+                * freed memsegs is seen by other core, that means the memseg
+                * has been allocated by allocator, which will come after this
+                * free call. Therefore, this store instruction (incrementing
+                * generation below) will be guaranteed to be seen by other core
+                * before the core sees the newly allocated memory.
+                */
+               ++priv->mr.dev_gen;
+               DEBUG("broadcasting local cache flush, gen=%d",
+                     priv->mr.dev_gen);
+               rte_smp_wmb();
+       }
+       rte_rwlock_write_unlock(&priv->mr.rwlock);
+#ifndef NDEBUG
+       if (rebuild)
+               mlx4_mr_dump_dev(dev);
+#endif
+}
+
+/**
+ * Callback for memory event.
+ *
+ * @param event_type
+ *   Memory event type.
+ * @param addr
+ *   Address of memory.
+ * @param len
+ *   Size of memory.
+ */
+void
+mlx4_mr_mem_event_cb(enum rte_mem_event event_type, const void *addr,
+                    size_t len)
+{
+       struct priv *priv;
+
+       switch (event_type) {
+       case RTE_MEM_EVENT_FREE:
+               rte_rwlock_read_lock(&mlx4_mem_event_rwlock);
+               /* Iterate all the existing mlx4 devices. */
+               LIST_FOREACH(priv, &mlx4_mem_event_cb_list, mem_event_cb)
+                       mlx4_mr_mem_event_free_cb(priv->dev, addr, len);
+               rte_rwlock_read_unlock(&mlx4_mem_event_rwlock);
+               break;
+       case RTE_MEM_EVENT_ALLOC:
+       default:
+               break;
+       }
+}
+
+/**
+ * Look up address in the global MR cache table. If not found, create a new MR.
+ * Insert the found/created entry to local bottom-half cache table.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param mr_ctrl
+ *   Pointer to per-queue MR control structure.
+ * @param[out] entry
+ *   Pointer to returning MR cache entry, found in the global cache or newly
+ *   created. If failed to create one, this is not written.
+ * @param addr
+ *   Search key.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on no match.
+ */
+static uint32_t
+mlx4_mr_lookup_dev(struct rte_eth_dev *dev, struct mlx4_mr_ctrl *mr_ctrl,
+                  struct mlx4_mr_cache *entry, uintptr_t addr)
+{
+       struct priv *priv = dev->data->dev_private;
+       struct mlx4_mr_btree *bt = &mr_ctrl->cache_bh;
+       uint16_t idx;
+       uint32_t lkey;
+
+       /* If local cache table is full, try to double it. */
+       if (unlikely(bt->len == bt->size))
+               mr_btree_expand(bt, bt->size << 1);
+       /* Look up in the global cache. */
+       rte_rwlock_read_lock(&priv->mr.rwlock);
+       lkey = mr_btree_lookup(&priv->mr.cache, &idx, addr);
+       if (lkey != UINT32_MAX) {
+               /* Found. */
+               *entry = (*priv->mr.cache.table)[idx];
+               rte_rwlock_read_unlock(&priv->mr.rwlock);
+               /*
+                * Update local cache. Even if it fails, return the found entry
+                * to update top-half cache. Next time, this entry will be found
+                * in the global cache.
+                */
+               mr_btree_insert(bt, entry);
+               return lkey;
+       }
+       rte_rwlock_read_unlock(&priv->mr.rwlock);
+       /* First time to see the address? Create a new MR. */
+       lkey = mlx4_mr_create(dev, entry, addr);
+       /*
+        * Update the local cache if successfully created a new global MR. Even
+        * if failed to create one, there's no action to take in this datapath
+        * code. As returning LKey is invalid, this will eventually make HW
+        * fail.
+        */
+       if (lkey != UINT32_MAX)
+               mr_btree_insert(bt, entry);
+       return lkey;
+}
+
+/**
+ * Bottom-half of LKey search on datapath. Firstly search in cache_bh[] and if
+ * misses, search in the global MR cache table and update the new entry to
+ * per-queue local caches.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param mr_ctrl
+ *   Pointer to per-queue MR control structure.
+ * @param addr
+ *   Search key.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on no match.
+ */
+static uint32_t
+mlx4_mr_addr2mr_bh(struct rte_eth_dev *dev, struct mlx4_mr_ctrl *mr_ctrl,
+                  uintptr_t addr)
+{
+       uint32_t lkey;
+       uint16_t bh_idx = 0;
+       /* Victim in top-half cache to replace with new entry. */
+       struct mlx4_mr_cache *repl = &mr_ctrl->cache[mr_ctrl->head];
+
+       /* Binary-search MR translation table. */
+       lkey = mr_btree_lookup(&mr_ctrl->cache_bh, &bh_idx, addr);
+       /* Update top-half cache. */
+       if (likely(lkey != UINT32_MAX)) {
+               *repl = (*mr_ctrl->cache_bh.table)[bh_idx];
+       } else {
+               /*
+                * If missed in local lookup table, search in the global cache
+                * and local cache_bh[] will be updated inside if possible.
+                * Top-half cache entry will also be updated.
+                */
+               lkey = mlx4_mr_lookup_dev(dev, mr_ctrl, repl, addr);
+               if (unlikely(lkey == UINT32_MAX))
+                       return UINT32_MAX;
+       }
+       /* Update the most recently used entry. */
+       mr_ctrl->mru = mr_ctrl->head;
+       /* Point to the next victim, the oldest. */
+       mr_ctrl->head = (mr_ctrl->head + 1) % MLX4_MR_CACHE_N;
+       return lkey;
+}
+
+/**
+ * Bottom-half of LKey search on Rx.
+ *
+ * @param rxq
+ *   Pointer to Rx queue structure.
+ * @param addr
+ *   Search key.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on no match.
+ */
+uint32_t
+mlx4_rx_addr2mr_bh(struct rxq *rxq, uintptr_t addr)
+{
+       struct mlx4_mr_ctrl *mr_ctrl = &rxq->mr_ctrl;
+       struct priv *priv = rxq->priv;
+
+       DEBUG("Rx queue %u: miss on top-half, mru=%u, head=%u, addr=%p",
+             rxq->stats.idx, mr_ctrl->mru, mr_ctrl->head, (void *)addr);
+       return mlx4_mr_addr2mr_bh(priv->dev, mr_ctrl, addr);
+}
+
+/**
+ * Bottom-half of LKey search on Tx.
+ *
+ * @param txq
+ *   Pointer to Tx queue structure.
+ * @param addr
+ *   Search key.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on no match.
+ */
+uint32_t
+mlx4_tx_addr2mr_bh(struct txq *txq, uintptr_t addr)
+{
+       struct mlx4_mr_ctrl *mr_ctrl = &txq->mr_ctrl;
+       struct priv *priv = txq->priv;
+
+       DEBUG("Tx queue %u: miss on top-half, mru=%u, head=%u, addr=%p",
+             txq->stats.idx, mr_ctrl->mru, mr_ctrl->head, (void *)addr);
+       return mlx4_mr_addr2mr_bh(priv->dev, mr_ctrl, addr);
+}
+
+/**
+ * Flush all of the local cache entries.
+ *
+ * @param mr_ctrl
+ *   Pointer to per-queue MR control structure.
+ */
+void
+mlx4_mr_flush_local_cache(struct mlx4_mr_ctrl *mr_ctrl)
+{
+       /* Reset the most-recently-used index. */
+       mr_ctrl->mru = 0;
+       /* Reset the linear search array. */
+       mr_ctrl->head = 0;
+       memset(mr_ctrl->cache, 0, sizeof(mr_ctrl->cache));
+       /* Reset the B-tree table. */
+       mr_ctrl->cache_bh.len = 1;
+       mr_ctrl->cache_bh.overflow = 0;
+       /* Update the generation number. */
+       mr_ctrl->cur_gen = *mr_ctrl->dev_gen_ptr;
+       DEBUG("mr_ctrl(%p): flushed, cur_gen=%d",
+             (void *)mr_ctrl, mr_ctrl->cur_gen);
+}
+
+/* Called during rte_mempool_mem_iter() by mlx4_mr_update_mp(). */
+static void
+mlx4_mr_update_mp_cb(struct rte_mempool *mp __rte_unused, void *opaque,
+                    struct rte_mempool_memhdr *memhdr,
+                    unsigned mem_idx __rte_unused)
+{
+       struct mr_update_mp_data *data = opaque;
+       uint32_t lkey;
+
+       /* Stop iteration if failed in the previous walk. */
+       if (data->ret < 0)
+               return;
+       /* Register address of the chunk and update local caches. */
+       lkey = mlx4_mr_addr2mr_bh(data->dev, data->mr_ctrl,
+                                 (uintptr_t)memhdr->addr);
+       if (lkey == UINT32_MAX)
+               data->ret = -1;
+}
+
+/**
+ * Register entire memory chunks in a Mempool.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ * @param mr_ctrl
+ *   Pointer to per-queue MR control structure.
+ * @param mp
+ *   Pointer to registering Mempool.
+ *
+ * @return
+ *   0 on success, -1 on failure.
+ */
+int
+mlx4_mr_update_mp(struct rte_eth_dev *dev, struct mlx4_mr_ctrl *mr_ctrl,
+                 struct rte_mempool *mp)
+{
+       struct mr_update_mp_data data = {
+               .dev = dev,
+               .mr_ctrl = mr_ctrl,
+               .ret = 0,
+       };
+
+       rte_mempool_mem_iter(mp, mlx4_mr_update_mp_cb, &data);
+       return data.ret;
+}
+
+#ifndef NDEBUG
+/**
+ * Dump all the created MRs and the global cache entries.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ */
+void
+mlx4_mr_dump_dev(struct rte_eth_dev *dev)
+{
+       struct priv *priv = dev->data->dev_private;
+       struct mlx4_mr *mr;
+       int mr_n = 0;
+       int chunk_n = 0;
+
+       rte_rwlock_read_lock(&priv->mr.rwlock);
+       /* Iterate all the existing MRs. */
+       LIST_FOREACH(mr, &priv->mr.mr_list, mr) {
+               unsigned int n;
+
+               DEBUG("port %u MR[%u], LKey = 0x%x, ms_n = %u, ms_bmp_n = %u",
+                     dev->data->port_id, mr_n++,
+                     rte_cpu_to_be_32(mr->ibv_mr->lkey),
+                     mr->ms_n, mr->ms_bmp_n);
+               if (mr->ms_n == 0)
+                       continue;
+               for (n = 0; n < mr->ms_bmp_n; ) {
+                       struct mlx4_mr_cache ret = { 0, };
+
+                       n = mr_find_next_chunk(mr, &ret, n);
+                       if (!ret.end)
+                               break;
+                       DEBUG("  chunk[%u], [0x%lx, 0x%lx)",
+                             chunk_n++, ret.start, ret.end);
+               }
+       }
+       DEBUG("port %u dumping global cache", dev->data->port_id);
+       mlx4_mr_btree_dump(&priv->mr.cache);
+       rte_rwlock_read_unlock(&priv->mr.rwlock);
+}
+#endif
+
+/**
+ * Release all the created MRs and resources. Remove device from memory 
callback
+ * list.
+ *
+ * @param dev
+ *   Pointer to Ethernet device.
+ */
+void
+mlx4_mr_release(struct rte_eth_dev *dev)
+{
+       struct priv *priv = dev->data->dev_private;
+       struct mlx4_mr *mr_next = LIST_FIRST(&priv->mr.mr_list);
+
+       /* Remove from memory callback device list. */
+       rte_rwlock_write_lock(&mlx4_mem_event_rwlock);
+       LIST_REMOVE(priv, mem_event_cb);
+       rte_rwlock_write_unlock(&mlx4_mem_event_rwlock);
+#ifndef NDEBUG
+       mlx4_mr_dump_dev(dev);
+#endif
+       rte_rwlock_write_lock(&priv->mr.rwlock);
+       /* Detach from MR list and move to free list. */
+       while (mr_next != NULL) {
+               struct mlx4_mr *mr = mr_next;
+
+               mr_next = LIST_NEXT(mr, mr);
+               LIST_REMOVE(mr, mr);
+               LIST_INSERT_HEAD(&priv->mr.mr_free_list, mr, mr);
+       }
+       LIST_INIT(&priv->mr.mr_list);
+       /* Free global cache. */
+       mlx4_mr_btree_free(&priv->mr.cache);
+       rte_rwlock_write_unlock(&priv->mr.rwlock);
+       /* Free all remaining MRs. */
+       mlx4_mr_garbage_collect(dev);
+}
diff --git a/drivers/net/mlx4/mlx4_mr.h b/drivers/net/mlx4/mlx4_mr.h
new file mode 100644
index 000000000..33305c0f8
--- /dev/null
+++ b/drivers/net/mlx4/mlx4_mr.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright 2018 6WIND S.A.
+ * Copyright 2018 Mellanox Technologies, Ltd
+ */
+
+#ifndef RTE_PMD_MLX4_MR_H_
+#define RTE_PMD_MLX4_MR_H_
+
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/queue.h>
+
+/* Verbs headers do not support -pedantic. */
+#ifdef PEDANTIC
+#pragma GCC diagnostic ignored "-Wpedantic"
+#endif
+#include <infiniband/verbs.h>
+#ifdef PEDANTIC
+#pragma GCC diagnostic error "-Wpedantic"
+#endif
+
+#include <rte_eal_memconfig.h>
+#include <rte_ethdev.h>
+#include <rte_rwlock.h>
+#include <rte_bitmap.h>
+
+/* Size of per-queue MR cache array for linear search. */
+#define MLX4_MR_CACHE_N 8
+
+/* Size of MR cache table for binary search. */
+#define MLX4_MR_BTREE_CACHE_N 256
+
+/* Memory Region object. */
+struct mlx4_mr {
+       LIST_ENTRY(mlx4_mr) mr; /**< Pointer to the prev/next entry. */
+       struct ibv_mr *ibv_mr; /* Verbs Memory Region. */
+       const struct rte_memseg_list *msl;
+       int ms_base_idx; /* Start index of msl->memseg_arr[]. */
+       int ms_n; /* Number of memsegs in use. */
+       uint32_t ms_bmp_n; /* Number of bits in memsegs bit-mask. */
+       struct rte_bitmap *ms_bmp; /* Bit-mask of memsegs belonged to MR. */
+};
+
+/* Cache entry for Memory Region. */
+struct mlx4_mr_cache {
+       uintptr_t start; /* Start address of MR. */
+       uintptr_t end; /* End address of MR. */
+       uint32_t lkey; /* rte_cpu_to_be_32(ibv_mr->lkey). */
+} __rte_packed;
+
+/* MR Cache table for Binary search. */
+struct mlx4_mr_btree {
+       uint16_t len; /* Number of entries. */
+       uint16_t size; /* Total number of entries. */
+       int overflow; /* Mark failure of table expansion. */
+       struct mlx4_mr_cache (*table)[];
+} __rte_packed;
+
+/* Per-queue MR control descriptor. */
+struct mlx4_mr_ctrl {
+       uint32_t *dev_gen_ptr; /* Generation number of device to poll. */
+       uint32_t cur_gen; /* Generation number saved to flush caches. */
+       uint16_t mru; /* Index of last hit entry in top-half cache. */
+       uint16_t head; /* Index of the oldest entry in top-half cache. */
+       struct mlx4_mr_cache cache[MLX4_MR_CACHE_N]; /* Cache for top-half. */
+       struct mlx4_mr_btree cache_bh; /* Cache for bottom-half. */
+} __rte_packed;
+
+/* First entry must be NULL for comparison. */
+#define MR_N(n) ((n) - 1)
+
+/* Whether there's only one entry in MR lookup table. */
+#define IS_SINGLE_MR(n) (MR_N(n) == 1)
+
+extern struct mlx4_dev_list  mlx4_mem_event_cb_list;
+extern rte_rwlock_t mlx4_mem_event_rwlock;
+
+void mlx4_mr_free(struct rte_eth_dev *dev, struct mlx4_mr *mr);
+int mlx4_mr_btree_init(struct mlx4_mr_btree *bt, int n, int socket);
+void mlx4_mr_btree_free(struct mlx4_mr_btree *bt);
+void mlx4_mr_btree_dump(struct mlx4_mr_btree *bt);
+void mlx4_mr_mem_event_cb(enum rte_mem_event event_type, const void *addr,
+                         size_t len);
+int mlx4_mr_update_mp(struct rte_eth_dev *dev, struct mlx4_mr_ctrl *mr_ctrl,
+                     struct rte_mempool *mp);
+void mlx4_mr_dump_dev(struct rte_eth_dev *dev);
+void mlx4_mr_release(struct rte_eth_dev *dev);
+
+/**
+ * Look up LKey from given lookup table by linear search. Firstly look up the
+ * last-hit entry. If miss, the entire array is searched. If found, update the
+ * last-hit index and return LKey.
+ *
+ * @param lkp_tbl
+ *   Pointer to lookup table.
+ * @param[in,out] cached_idx
+ *   Pointer to last-hit index.
+ * @param n
+ *   Size of lookup table.
+ * @param addr
+ *   Search key.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on no match.
+ */
+static __rte_always_inline uint32_t
+mlx4_mr_lookup_cache(struct mlx4_mr_cache *lkp_tbl, uint16_t *cached_idx,
+                    uint16_t n, uintptr_t addr)
+{
+       uint16_t idx;
+
+       if (likely(addr >= lkp_tbl[*cached_idx].start &&
+                  addr < lkp_tbl[*cached_idx].end))
+               return lkp_tbl[*cached_idx].lkey;
+       for (idx = 0; idx < n && lkp_tbl[idx].start != 0; ++idx) {
+               if (addr >= lkp_tbl[idx].start &&
+                   addr < lkp_tbl[idx].end) {
+                       /* Found. */
+                       *cached_idx = idx;
+                       return lkp_tbl[idx].lkey;
+               }
+       }
+       return UINT32_MAX;
+}
+
+#endif /* RTE_PMD_MLX4_MR_H_ */
diff --git a/drivers/net/mlx4/mlx4_rxq.c b/drivers/net/mlx4/mlx4_rxq.c
index 5621d5bd4..ad706be82 100644
--- a/drivers/net/mlx4/mlx4_rxq.c
+++ b/drivers/net/mlx4/mlx4_rxq.c
@@ -488,6 +488,7 @@ mlx4_rxq_attach(struct rxq *rxq)
        }
 
        struct priv *priv = rxq->priv;
+       struct rte_eth_dev *dev = priv->dev;
        const uint32_t elts_n = 1 << rxq->elts_n;
        const uint32_t sges_n = 1 << rxq->sges_n;
        struct rte_mbuf *(*elts)[elts_n] = rxq->elts;
@@ -552,6 +553,11 @@ mlx4_rxq_attach(struct rxq *rxq)
                msg = "failed to obtain device information from WQ/CQ objects";
                goto error;
        }
+       /* Pre-register Rx mempool. */
+       DEBUG("port %u Rx queue %u registering mp %s having %u chunks",
+             priv->dev->data->port_id, rxq->stats.idx,
+             rxq->mp->name, rxq->mp->nb_mem_chunks);
+       mlx4_mr_update_mp(dev, &rxq->mr_ctrl, rxq->mp);
        wqes = (volatile struct mlx4_wqe_data_seg (*)[])
                ((uintptr_t)dv_rwq.buf.buf + dv_rwq.rq.offset);
        for (i = 0; i != RTE_DIM(*elts); ++i) {
@@ -583,7 +589,7 @@ mlx4_rxq_attach(struct rxq *rxq)
                        .addr = rte_cpu_to_be_64(rte_pktmbuf_mtod(buf,
                                                                  uintptr_t)),
                        .byte_count = rte_cpu_to_be_32(buf->data_len),
-                       .lkey = UINT32_MAX,
+                       .lkey = mlx4_rx_mb2mr(rxq, buf),
                };
                (*elts)[i] = buf;
        }
@@ -883,6 +889,11 @@ mlx4_rx_queue_setup(struct rte_eth_dev *dev, uint16_t idx, 
uint16_t desc,
                      1 << rxq->sges_n);
                goto error;
        }
+       if (mlx4_mr_btree_init(&rxq->mr_ctrl.cache_bh,
+                              MLX4_MR_BTREE_CACHE_N, socket)) {
+               /* rte_errno is already set. */
+               goto error;
+       }
        if (dev->data->dev_conf.intr_conf.rxq) {
                rxq->channel = mlx4_glue->create_comp_channel(priv->ctx);
                if (rxq->channel == NULL) {
@@ -940,5 +951,6 @@ mlx4_rx_queue_release(void *dpdk_rxq)
        assert(!rxq->rq_db);
        if (rxq->channel)
                claim_zero(mlx4_glue->destroy_comp_channel(rxq->channel));
+       mlx4_mr_btree_free(&rxq->mr_ctrl.cache_bh);
        rte_free(rxq);
 }
diff --git a/drivers/net/mlx4/mlx4_rxtx.c b/drivers/net/mlx4/mlx4_rxtx.c
index 21ffd435a..f3899c79a 100644
--- a/drivers/net/mlx4/mlx4_rxtx.c
+++ b/drivers/net/mlx4/mlx4_rxtx.c
@@ -344,24 +344,6 @@ mlx4_txq_complete(struct txq *txq, const unsigned int 
elts_m,
 }
 
 /**
- * Get memory pool (MP) from mbuf. If mbuf is indirect, the pool from which
- * the cloned mbuf is allocated is returned instead.
- *
- * @param buf
- *   Pointer to mbuf.
- *
- * @return
- *   Memory pool where data is located for given mbuf.
- */
-static struct rte_mempool *
-mlx4_txq_mb2mp(struct rte_mbuf *buf)
-{
-       if (unlikely(RTE_MBUF_INDIRECT(buf)))
-               return rte_mbuf_from_indirect(buf)->pool;
-       return buf->pool;
-}
-
-/**
  * Write Tx data segment to the SQ.
  *
  * @param dseg
@@ -378,7 +360,7 @@ mlx4_fill_tx_data_seg(volatile struct mlx4_wqe_data_seg 
*dseg,
                       uint32_t lkey, uintptr_t addr, rte_be32_t  byte_count)
 {
        dseg->addr = rte_cpu_to_be_64(addr);
-       dseg->lkey = rte_cpu_to_be_32(lkey);
+       dseg->lkey = lkey;
 #if RTE_CACHE_LINE_SIZE < 64
        /*
         * Need a barrier here before writing the byte_count
@@ -437,7 +419,7 @@ mlx4_tx_burst_segs(struct rte_mbuf *buf, struct txq *txq,
        goto txbb_tail_segs;
 txbb_head_seg:
        /* Memory region key (big endian) for this memory pool. */
-       lkey = mlx4_txq_mp2mr(txq, mlx4_txq_mb2mp(sbuf));
+       lkey = mlx4_tx_mb2mr(txq, sbuf);
        if (unlikely(lkey == (uint32_t)-1)) {
                DEBUG("%p: unable to get MP <-> MR association",
                      (void *)txq);
@@ -449,7 +431,7 @@ mlx4_tx_burst_segs(struct rte_mbuf *buf, struct txq *txq,
                dseg = (volatile struct mlx4_wqe_data_seg *)
                        sq->buf;
        dseg->addr = rte_cpu_to_be_64(rte_pktmbuf_mtod(sbuf, uintptr_t));
-       dseg->lkey = rte_cpu_to_be_32(lkey);
+       dseg->lkey = lkey;
        /*
         * This data segment starts at the beginning of a new
         * TXBB, so we need to postpone its byte_count writing
@@ -469,7 +451,7 @@ mlx4_tx_burst_segs(struct rte_mbuf *buf, struct txq *txq,
        /* Jump to default if there are more than two segments remaining. */
        switch (nb_segs) {
        default:
-               lkey = mlx4_txq_mp2mr(txq, mlx4_txq_mb2mp(sbuf));
+               lkey = mlx4_tx_mb2mr(txq, sbuf);
                if (unlikely(lkey == (uint32_t)-1)) {
                        DEBUG("%p: unable to get MP <-> MR association",
                              (void *)txq);
@@ -485,7 +467,7 @@ mlx4_tx_burst_segs(struct rte_mbuf *buf, struct txq *txq,
                nb_segs--;
                /* fallthrough */
        case 2:
-               lkey = mlx4_txq_mp2mr(txq, mlx4_txq_mb2mp(sbuf));
+               lkey = mlx4_tx_mb2mr(txq, sbuf);
                if (unlikely(lkey == (uint32_t)-1)) {
                        DEBUG("%p: unable to get MP <-> MR association",
                              (void *)txq);
@@ -501,7 +483,7 @@ mlx4_tx_burst_segs(struct rte_mbuf *buf, struct txq *txq,
                nb_segs--;
                /* fallthrough */
        case 1:
-               lkey = mlx4_txq_mp2mr(txq, mlx4_txq_mb2mp(sbuf));
+               lkey = mlx4_tx_mb2mr(txq, sbuf);
                if (unlikely(lkey == (uint32_t)-1)) {
                        DEBUG("%p: unable to get MP <-> MR association",
                              (void *)txq);
@@ -611,7 +593,7 @@ mlx4_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, 
uint16_t pkts_n)
                                elt->buf = NULL;
                                break;
                        }
-                       lkey = mlx4_txq_mp2mr(txq, mlx4_txq_mb2mp(buf));
+                       lkey = mlx4_tx_mb2mr(txq, buf);
                        if (unlikely(lkey == (uint32_t)-1)) {
                                /* MR does not exist. */
                                DEBUG("%p: unable to get MP <-> MR association",
@@ -966,6 +948,9 @@ mlx4_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, 
uint16_t pkts_n)
                 * changes.
                 */
                scat->addr = rte_cpu_to_be_64(rte_pktmbuf_mtod(rep, uintptr_t));
+               /* If there's only one MR, no need to replace LKey in WQE. */
+               if (unlikely(!IS_SINGLE_MR(rxq->mr_ctrl.cache_bh.len)))
+                       scat->lkey = mlx4_rx_mb2mr(rxq, rep);
                if (len > seg->data_len) {
                        len -= seg->data_len;
                        ++pkt->nb_segs;
diff --git a/drivers/net/mlx4/mlx4_rxtx.h b/drivers/net/mlx4/mlx4_rxtx.h
index 2f9d3798b..4c025e3a0 100644
--- a/drivers/net/mlx4/mlx4_rxtx.h
+++ b/drivers/net/mlx4/mlx4_rxtx.h
@@ -25,6 +25,7 @@
 
 #include "mlx4.h"
 #include "mlx4_prm.h"
+#include "mlx4_mr.h"
 
 /** Rx queue counters. */
 struct mlx4_rxq_stats {
@@ -46,6 +47,7 @@ struct rxq {
        uint16_t port_id; /**< Port ID for incoming packets. */
        uint16_t sges_n; /**< Number of segments per packet (log2 value). */
        uint16_t elts_n; /**< Mbuf queue size (log2 value). */
+       struct mlx4_mr_ctrl mr_ctrl; /* MR control descriptor. */
        struct rte_mbuf *(*elts)[]; /**< Rx elements. */
        volatile struct mlx4_wqe_data_seg (*wqes)[]; /**< HW queue entries. */
        volatile uint32_t *rq_db; /**< RQ doorbell record. */
@@ -100,6 +102,7 @@ struct txq {
        int elts_comp_cd; /**< Countdown for next completion. */
        unsigned int elts_comp_cd_init; /**< Initial value for countdown. */
        unsigned int elts_n; /**< (*elts)[] length. */
+       struct mlx4_mr_ctrl mr_ctrl; /* MR control descriptor. */
        struct txq_elt (*elts)[]; /**< Tx elements. */
        struct mlx4_txq_stats stats; /**< Tx queue counters. */
        uint32_t max_inline; /**< Max inline send size. */
@@ -155,12 +158,70 @@ int mlx4_tx_queue_setup(struct rte_eth_dev *dev, uint16_t 
idx,
                        const struct rte_eth_txconf *conf);
 void mlx4_tx_queue_release(void *dpdk_txq);
 
-static inline uint32_t
-mlx4_txq_mp2mr(struct txq *txq, struct rte_mempool *mp)
+/* mlx4_mr.c */
+
+void mlx4_mr_flush_local_cache(struct mlx4_mr_ctrl *mr_ctrl);
+uint32_t mlx4_rx_addr2mr_bh(struct rxq *rxq, uintptr_t addr);
+uint32_t mlx4_tx_addr2mr_bh(struct txq *txq, uintptr_t addr);
+
+/**
+ * Query LKey from a packet buffer for Rx. No need to flush local caches for Rx
+ * as mempool is pre-configured and static.
+ *
+ * @param rxq
+ *   Pointer to Rx queue structure.
+ * @param addr
+ *   Address to search.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on no match.
+ */
+static __rte_always_inline uint32_t
+mlx4_rx_addr2mr(struct rxq *rxq, uintptr_t addr)
+{
+       struct mlx4_mr_ctrl *mr_ctrl = &rxq->mr_ctrl;
+       uint32_t lkey;
+
+       /* Linear search on MR cache array. */
+       lkey = mlx4_mr_lookup_cache(mr_ctrl->cache, &mr_ctrl->mru,
+                                   MLX4_MR_CACHE_N, addr);
+       if (likely(lkey != UINT32_MAX))
+               return lkey;
+       /* Take slower bottom-half (Binary Search) on miss. */
+       return mlx4_rx_addr2mr_bh(rxq, addr);
+}
+
+#define mlx4_rx_mb2mr(rxq, mb) mlx4_rx_addr2mr(rxq, 
(uintptr_t)((mb)->buf_addr))
+
+/**
+ * Query LKey from a packet buffer for Tx. If not found, add the mempool.
+ *
+ * @param txq
+ *   Pointer to Tx queue structure.
+ * @param addr
+ *   Address to search.
+ *
+ * @return
+ *   Searched LKey on success, UINT32_MAX on no match.
+ */
+static __rte_always_inline uint32_t
+mlx4_tx_addr2mr(struct txq *txq, uintptr_t addr)
 {
-       (void)txq;
-       (void)mp;
-       return UINT32_MAX;
+       struct mlx4_mr_ctrl *mr_ctrl = &txq->mr_ctrl;
+       uint32_t lkey;
+
+       /* Check generation bit to see if there's any change on existing MRs. */
+       if (unlikely(*mr_ctrl->dev_gen_ptr != mr_ctrl->cur_gen))
+               mlx4_mr_flush_local_cache(mr_ctrl);
+       /* Linear search on MR cache array. */
+       lkey = mlx4_mr_lookup_cache(mr_ctrl->cache, &mr_ctrl->mru,
+                                   MLX4_MR_CACHE_N, addr);
+       if (likely(lkey != UINT32_MAX))
+               return lkey;
+       /* Take slower bottom-half (binary search) on miss. */
+       return mlx4_tx_addr2mr_bh(txq, addr);
 }
 
+#define mlx4_tx_mb2mr(rxq, mb) mlx4_tx_addr2mr(rxq, 
(uintptr_t)((mb)->buf_addr))
+
 #endif /* MLX4_RXTX_H_ */
diff --git a/drivers/net/mlx4/mlx4_txq.c b/drivers/net/mlx4/mlx4_txq.c
index 5ea09b0b0..337ed9a1a 100644
--- a/drivers/net/mlx4/mlx4_txq.c
+++ b/drivers/net/mlx4/mlx4_txq.c
@@ -346,6 +346,13 @@ mlx4_tx_queue_setup(struct rte_eth_dev *dev, uint16_t idx, 
uint16_t desc,
        /* Save first wqe pointer in the first element. */
        (&(*txq->elts)[0])->wqe =
                (volatile struct mlx4_wqe_ctrl_seg *)txq->msq.buf;
+       if (mlx4_mr_btree_init(&txq->mr_ctrl.cache_bh,
+                              MLX4_MR_BTREE_CACHE_N, socket)) {
+               /* rte_errno is already set. */
+               goto error;
+       }
+       /* Save pointer of global generation number to check memory event. */
+       txq->mr_ctrl.dev_gen_ptr = &priv->mr.dev_gen;
        DEBUG("%p: adding Tx queue %p to list", (void *)dev, (void *)txq);
        dev->data->tx_queues[idx] = txq;
        return 0;
@@ -386,5 +393,6 @@ mlx4_tx_queue_release(void *dpdk_txq)
                claim_zero(mlx4_glue->destroy_qp(txq->qp));
        if (txq->cq)
                claim_zero(mlx4_glue->destroy_cq(txq->cq));
+       mlx4_mr_btree_free(&txq->mr_ctrl.cache_bh);
        rte_free(txq);
 }
-- 
2.11.0

Reply via email to