Fix RDMA connection leak which was preventing stable functioning of RDMA :)

src/messenger.cpp

@@ -490,7 +490,14 @@ void osd_messenger_t::check_peer_config(osd_client_t *cl)
                     fprintf(stderr, "Connected to OSD %lu using RDMA\n", cl->osd_num);
                 }
                 cl->peer_state = PEER_RDMA;
-                tfd->set_fd_handler(cl->peer_fd, false, NULL);
+                tfd->set_fd_handler(cl->peer_fd, false, [this](int peer_fd, int epoll_events)
+                {
+                    // Do not miss the disconnection!
+                    if (epoll_events & EPOLLRDHUP)
+                    {
+                        handle_peer_epoll(peer_fd, epoll_events);
+                    }
+                });
                 // Add the initial receive request
                 try_recv_rdma(cl);
             }

src/msgr_rdma.cpp

@@ -47,25 +47,8 @@ msgr_rdma_connection_t::~msgr_rdma_connection_t()
     if (qp)
         ibv_destroy_qp(qp);
     if (recv_buffers.size())
-    {
         for (auto b: recv_buffers)
-        {
-            if (b.mr)
-                ibv_dereg_mr(b.mr);
-            free(b.buf);
-        }
-        recv_buffers.clear();
-    }
-    if (send_mrs.size())
-    {
-        for (auto & mr: send_mrs)
-        {
-            if (mr)
-                ibv_dereg_mr(mr);
-            mr = NULL;
-        }
-        send_mrs.clear();
-    }
+            free(b);
 }
 
 msgr_rdma_context_t *msgr_rdma_context_t::create(const char *ib_devname, uint8_t ib_port, uint8_t gid_index, uint32_t mtu, int log_level)
@@ -158,24 +141,18 @@ msgr_rdma_context_t *msgr_rdma_context_t::create(const char *ib_devname, uint8_t
             !(ctx->attrx.odp_caps.per_transport_caps.rc_odp_caps & IBV_ODP_SUPPORT_SEND) ||
             !(ctx->attrx.odp_caps.per_transport_caps.rc_odp_caps & IBV_ODP_SUPPORT_RECV))
         {
-            ctx->odp = false;
-            if (log_level > 0)
-                fprintf(stderr, "The RDMA device isn't implicit ODP (On-Demand Paging) capable. Falling back to slower version without ODP\n");
-        }
-        else
-            ctx->odp = true;
-    }
-
-    if (ctx->odp)
-    {
-        ctx->mr = ibv_reg_mr(ctx->pd, NULL, SIZE_MAX, IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_ON_DEMAND);
-        if (!ctx->mr)
-        {
-            fprintf(stderr, "Couldn't register RDMA memory region\n");
+            fprintf(stderr, "The RDMA device isn't implicit ODP (On-Demand Paging) capable or does not support RC send and receive with ODP\n");
             goto cleanup;
         }
     }
 
+    ctx->mr = ibv_reg_mr(ctx->pd, NULL, SIZE_MAX, IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_ON_DEMAND);
+    if (!ctx->mr)
+    {
+        fprintf(stderr, "Couldn't register RDMA memory region\n");
+        goto cleanup;
+    }
+
     ctx->channel = ibv_create_comp_channel(ctx->context);
     if (!ctx->channel)
     {
@@ -399,6 +376,7 @@ bool osd_messenger_t::try_send_rdma(osd_client_t *cl)
     ibv_sge sge[rc->max_sge];
     while (rc->send_pos < cl->send_list.size())
     {
+        iovec & iov = cl->send_list[rc->send_pos];
         if (op_size >= rc->max_msg || op_sge >= rc->max_sge)
         {
             rc->send_sizes.push_back(op_size);
@@ -410,23 +388,12 @@ bool osd_messenger_t::try_send_rdma(osd_client_t *cl)
                 break;
             }
         }
-        iovec & iov = cl->send_list[rc->send_pos];
-        if (!rdma_context->odp && rc->send_mrs.size() <= rc->send_pos)
-        {
-            ibv_mr *mr = ibv_reg_mr(rdma_context->pd, iov.iov_base, iov.iov_len, IBV_ACCESS_LOCAL_WRITE);
-            if (!mr)
-            {
-                fprintf(stderr, "Failed to register RDMA memory region: %s\n", strerror(errno));
-                exit(1);
-            }
-            rc->send_mrs.push_back(mr);
-        }
         uint32_t len = (uint32_t)(op_size+iov.iov_len-rc->send_buf_pos < rc->max_msg
             ? iov.iov_len-rc->send_buf_pos : rc->max_msg-op_size);
         sge[op_sge++] = {
             .addr = (uintptr_t)((uint8_t*)iov.iov_base+rc->send_buf_pos),
             .length = len,
-            .lkey = rdma_context->odp ? rc->ctx->mr->lkey : rc->send_mrs[rc->send_pos]->lkey,
+            .lkey = rc->ctx->mr->lkey,
         };
         op_size += len;
         rc->send_buf_pos += len;
@@ -444,12 +411,12 @@ bool osd_messenger_t::try_send_rdma(osd_client_t *cl)
     return true;
 }
 
-static void try_recv_rdma_wr(osd_client_t *cl, msgr_rdma_buf_t b)
+static void try_recv_rdma_wr(osd_client_t *cl, void *buf)
 {
     ibv_sge sge = {
-        .addr = (uintptr_t)b.buf,
+        .addr = (uintptr_t)buf,
         .length = (uint32_t)cl->rdma_conn->max_msg,
-        .lkey = !b.mr ? cl->rdma_conn->ctx->mr->lkey : b.mr->lkey,
+        .lkey = cl->rdma_conn->ctx->mr->lkey,
     };
     ibv_recv_wr *bad_wr = NULL;
     ibv_recv_wr wr = {
@@ -471,19 +438,9 @@ bool osd_messenger_t::try_recv_rdma(osd_client_t *cl)
     auto rc = cl->rdma_conn;
     while (rc->cur_recv < rc->max_recv)
     {
-        msgr_rdma_buf_t b;
-        b.buf = malloc_or_die(rc->max_msg);
-        if (!rdma_context->odp)
-        {
-            b.mr = ibv_reg_mr(rdma_context->pd, b.buf, rc->max_msg, IBV_ACCESS_LOCAL_WRITE);
-            if (!b.mr)
-            {
-                fprintf(stderr, "Failed to register RDMA memory region: %s\n", strerror(errno));
-                exit(1);
-            }
-        }
-        rc->recv_buffers.push_back(b);
-        try_recv_rdma_wr(cl, b);
+        void *buf = malloc_or_die(rc->max_msg);
+        rc->recv_buffers.push_back(buf);
+        try_recv_rdma_wr(cl, buf);
     }
     return true;
 }
@@ -535,7 +492,7 @@ void osd_messenger_t::handle_rdma_events()
             if (!is_send)
             {
                 rc->cur_recv--;
-                if (!handle_read_buffer(cl, rc->recv_buffers[rc->next_recv_buf].buf, wc[i].byte_len))
+                if (!handle_read_buffer(cl, rc->recv_buffers[rc->next_recv_buf], wc[i].byte_len))
                 {
                     // handle_read_buffer may stop the client
                     continue;
@@ -570,11 +527,6 @@ void osd_messenger_t::handle_rdma_events()
                 rc->send_pos -= send_pos;
                 for (int i = 0; i < send_pos; i++)
                 {
-                    if (!rdma_context->odp)
-                    {
-                        ibv_dereg_mr(rc->send_mrs[i]);
-                        rc->send_mrs[i] = NULL;
-                    }
                     if (cl->outbox[i].flags & MSGR_SENDP_FREE)
                     {
                         // Reply fully sent
@@ -583,8 +535,6 @@ void osd_messenger_t::handle_rdma_events()
                 }
                 if (send_pos > 0)
                 {
-                    if (!rdma_context->odp)
-                        rc->send_mrs.erase(rc->send_mrs.begin(), rc->send_mrs.begin()+send_pos);
                     cl->send_list.erase(cl->send_list.begin(), cl->send_list.begin()+send_pos);
                     cl->outbox.erase(cl->outbox.begin(), cl->outbox.begin()+send_pos);
                 }

src/msgr_rdma.h

@@ -23,7 +23,6 @@ struct msgr_rdma_context_t
     ibv_device *dev = NULL;
     ibv_device_attr_ex attrx;
     ibv_pd *pd = NULL;
-    bool odp = false;
     ibv_mr *mr = NULL;
     ibv_comp_channel *channel = NULL;
     ibv_cq *cq = NULL;
@@ -40,12 +39,6 @@ struct msgr_rdma_context_t
     ~msgr_rdma_context_t();
 };
 
-struct msgr_rdma_buf_t
-{
-    void *buf = NULL;
-    ibv_mr *mr = NULL;
-};
-
 struct msgr_rdma_connection_t
 {
     msgr_rdma_context_t *ctx = NULL;
@@ -57,9 +50,8 @@ struct msgr_rdma_connection_t
 
     int send_pos = 0, send_buf_pos = 0;
     int next_recv_buf = 0;
-    std::vector<msgr_rdma_buf_t> recv_buffers;
+    std::vector<void*> recv_buffers;
     std::vector<uint64_t> send_sizes;
-    std::vector<ibv_mr*> send_mrs;
 
     ~msgr_rdma_connection_t();
     static msgr_rdma_connection_t *create(msgr_rdma_context_t *ctx, uint32_t max_send, uint32_t max_recv, uint32_t max_sge, uint32_t max_msg);

src/msgr_send.cpp

@@ -3,6 +3,7 @@
 
 #define _XOPEN_SOURCE
 #include <limits.h>
+#include <sys/epoll.h>
 
 #include "messenger.h"
 
@@ -283,7 +284,14 @@ void osd_messenger_t::handle_send(int result, osd_client_t *cl)
                 fprintf(stderr, "Successfully connected with client %d using RDMA\n", cl->peer_fd);
             }
             cl->peer_state = PEER_RDMA;
-            tfd->set_fd_handler(cl->peer_fd, false, NULL);
+            tfd->set_fd_handler(cl->peer_fd, false, [this](int peer_fd, int epoll_events)
+            {
+                // Do not miss the disconnection!
+                if (epoll_events & EPOLLRDHUP)
+                {
+                    handle_peer_epoll(peer_fd, epoll_events);
+                }
+            });
             // Add the initial receive request
             try_recv_rdma(cl);
         }