Re: [Qemu-devel] [PATCH 09/10] hw/rdma: Free all receive buffers when QP is destroyed

[Marcel Apfelbaum <marcel.apfelbaum@gmail.com>]

On 1/31/19 3:08 PM, Yuval Shaia wrote:
> When QP is destroyed the backend QP is destroyed as well. This ensures
> we clean all received buffer we posted to it.
> However, a contexts of these buffers are still remain in the device.

I think without 'a' and without 'are'

> Fix it by maintaining a list of buffer's context and free them when QP
> is destroyed.
>
> Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
> ---
>   hw/rdma/rdma_backend.c      | 25 +++++++++++++++++++------
>   hw/rdma/rdma_backend.h      |  2 +-
>   hw/rdma/rdma_backend_defs.h |  1 +
>   hw/rdma/rdma_rm.c           |  2 +-
>   4 files changed, 22 insertions(+), 8 deletions(-)
>
> diff --git a/hw/rdma/rdma_backend.c b/hw/rdma/rdma_backend.c
> index 65b28aa5b2..3283461b15 100644
> --- a/hw/rdma/rdma_backend.c
> +++ b/hw/rdma/rdma_backend.c
> @@ -39,6 +39,7 @@
>   typedef struct BackendCtx {
>       void *up_ctx;
>       struct ibv_sge sge; /* Used to save MAD recv buffer */
> +    RdmaBackendQP *backend_qp; /* To maintain recv buffers */
>   } BackendCtx;
>   
>   struct backend_umad {
> @@ -90,7 +91,8 @@ static void clean_recv_mads(RdmaBackendDev *backend_dev)
>       } while (cqe_ctx_id != -ENOENT);
>   }
>   
> -static int rdma_poll_cq(RdmaDeviceResources *rdma_dev_res, struct ibv_cq *ibcq)
> +static int rdma_poll_cq(RdmaBackendDev *backend_dev,
> +                        RdmaDeviceResources *rdma_dev_res, struct ibv_cq *ibcq)
>   {
>       int i, ne, total_ne = 0;
>       BackendCtx *bctx;
> @@ -113,6 +115,9 @@ static int rdma_poll_cq(RdmaDeviceResources *rdma_dev_res, struct ibv_cq *ibcq)
>   
>               comp_handler(bctx->up_ctx, &wc[i]);
>   
> +            bctx->backend_qp->cqe_ctx_list =
> +                g_slist_remove(bctx->backend_qp->cqe_ctx_list,
> +                               GINT_TO_POINTER(wc[i].wr_id));

No synchronization needed ?

Thanks,
Marcel

>               rdma_rm_dealloc_cqe_ctx(rdma_dev_res, wc[i].wr_id);
>               g_free(bctx);
>           }
> @@ -173,14 +178,12 @@ static void *comp_handler_thread(void *arg)
>               }
>   
>               backend_dev->rdma_dev_res->stats.poll_cq_from_bk++;
> -            rdma_poll_cq(backend_dev->rdma_dev_res, ev_cq);
> +            rdma_poll_cq(backend_dev, backend_dev->rdma_dev_res, ev_cq);
>   
>               ibv_ack_cq_events(ev_cq, 1);
>           }
>       }
>   
> -    /* TODO: Post cqe for all remaining buffs that were posted */
> -
>       backend_dev->comp_thread.is_running = false;
>   
>       qemu_thread_exit(0);
> @@ -307,7 +310,7 @@ int rdma_backend_query_port(RdmaBackendDev *backend_dev,
>   int rdma_backend_poll_cq(RdmaDeviceResources *rdma_dev_res, RdmaBackendCQ *cq)
>   {
>       rdma_dev_res->stats.poll_cq_from_guest++;
> -    return rdma_poll_cq(rdma_dev_res, cq->ibcq);
> +    return rdma_poll_cq(cq->backend_dev, rdma_dev_res, cq->ibcq);
>   }
>   
>   static GHashTable *ah_hash;
> @@ -494,6 +497,7 @@ void rdma_backend_post_send(RdmaBackendDev *backend_dev,
>   
>       bctx = g_malloc0(sizeof(*bctx));
>       bctx->up_ctx = ctx;
> +    bctx->backend_qp = qp;
>   
>       rc = rdma_rm_alloc_cqe_ctx(backend_dev->rdma_dev_res, &bctx_id, bctx);
>       if (unlikely(rc)) {
> @@ -501,6 +505,9 @@ void rdma_backend_post_send(RdmaBackendDev *backend_dev,
>           goto err_free_bctx;
>       }
>   
> +    qp->cqe_ctx_list = g_slist_append(qp->cqe_ctx_list,
> +                                      GINT_TO_POINTER(bctx_id));
> +
>       rc = build_host_sge_array(backend_dev->rdma_dev_res, new_sge, sge, num_sge,
>                                 &backend_dev->rdma_dev_res->stats.tx_len);
>       if (rc) {
> @@ -608,6 +615,7 @@ void rdma_backend_post_recv(RdmaBackendDev *backend_dev,
>   
>       bctx = g_malloc0(sizeof(*bctx));
>       bctx->up_ctx = ctx;
> +    bctx->backend_qp = qp;
>   
>       rc = rdma_rm_alloc_cqe_ctx(rdma_dev_res, &bctx_id, bctx);
>       if (unlikely(rc)) {
> @@ -615,6 +623,9 @@ void rdma_backend_post_recv(RdmaBackendDev *backend_dev,
>           goto err_free_bctx;
>       }
>   
> +    qp->cqe_ctx_list = g_slist_append(qp->cqe_ctx_list,
> +                                      GINT_TO_POINTER(bctx_id));
> +
>       rc = build_host_sge_array(rdma_dev_res, new_sge, sge, num_sge,
>                                 &backend_dev->rdma_dev_res->stats.rx_bufs_len);
>       if (rc) {
> @@ -910,11 +921,13 @@ int rdma_backend_query_qp(RdmaBackendQP *qp, struct ibv_qp_attr *attr,
>       return ibv_query_qp(qp->ibqp, attr, attr_mask, init_attr);
>   }
>   
> -void rdma_backend_destroy_qp(RdmaBackendQP *qp)
> +void rdma_backend_destroy_qp(RdmaBackendQP *qp, RdmaDeviceResources *dev_res)
>   {
>       if (qp->ibqp) {
>           ibv_destroy_qp(qp->ibqp);
>       }
> +    g_slist_foreach(qp->cqe_ctx_list, free_cqe_ctx, dev_res);
> +    g_slist_free(qp->cqe_ctx_list);
>   }
>   
>   #define CHK_ATTR(req, dev, member, fmt) ({ \
> diff --git a/hw/rdma/rdma_backend.h b/hw/rdma/rdma_backend.h
> index 6abc367a52..798a12f28f 100644
> --- a/hw/rdma/rdma_backend.h
> +++ b/hw/rdma/rdma_backend.h
> @@ -103,7 +103,7 @@ int rdma_backend_qp_state_rts(RdmaBackendQP *qp, uint8_t qp_type,
>                                 uint32_t sq_psn, uint32_t qkey, bool use_qkey);
>   int rdma_backend_query_qp(RdmaBackendQP *qp, struct ibv_qp_attr *attr,
>                             int attr_mask, struct ibv_qp_init_attr *init_attr);
> -void rdma_backend_destroy_qp(RdmaBackendQP *qp);
> +void rdma_backend_destroy_qp(RdmaBackendQP *qp, RdmaDeviceResources *dev_res);
>   
>   void rdma_backend_post_send(RdmaBackendDev *backend_dev,
>                               RdmaBackendQP *qp, uint8_t qp_type,
> diff --git a/hw/rdma/rdma_backend_defs.h b/hw/rdma/rdma_backend_defs.h
> index bec0457f25..2306bbd18e 100644
> --- a/hw/rdma/rdma_backend_defs.h
> +++ b/hw/rdma/rdma_backend_defs.h
> @@ -66,6 +66,7 @@ typedef struct RdmaBackendQP {
>       struct ibv_pd *ibpd;
>       struct ibv_qp *ibqp;
>       uint8_t sgid_idx;
> +    GSList *cqe_ctx_list;
>   } RdmaBackendQP;
>   
>   #endif
> diff --git a/hw/rdma/rdma_rm.c b/hw/rdma/rdma_rm.c
> index ff536e356b..c7b9ef17f8 100644
> --- a/hw/rdma/rdma_rm.c
> +++ b/hw/rdma/rdma_rm.c
> @@ -485,7 +485,7 @@ void rdma_rm_dealloc_qp(RdmaDeviceResources *dev_res, uint32_t qp_handle)
>           return;
>       }
>   
> -    rdma_backend_destroy_qp(&qp->backend_qp);
> +    rdma_backend_destroy_qp(&qp->backend_qp, dev_res);
>   
>       rdma_res_tbl_dealloc(&dev_res->qp_tbl, qp->qpn);
>   }