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

[Yuval Shaia <yuval.shaia@oracle.com>]

On Wed, Feb 06, 2019 at 12:23:25PM +0200, Marcel Apfelbaum wrote:
> 
> 
> 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

Agree, thanks!

> 
> >               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);
> >   }
> 
>