From: Chuck Lever <chuck.lever@xxxxxxxxxx>
DMA unmapping can take quite some time, so it should not be handled
in a single-threaded completion handler. Defer releasing send_ctxts
to the recently-added workqueue.
With this patch, DMA unmapping can be handled in parallel, and it
does not cause head-of-queue blocking of Send completions.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/sunrpc/svc_rdma.h | 2 ++
net/sunrpc/xprtrdma/svc_rdma_sendto.c | 34 ++++++++++++++++++++++++---------
2 files changed, 27 insertions(+), 9 deletions(-)
diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index e18c94e816b3..ab250017b99f 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -152,7 +152,9 @@ struct svc_rdma_recv_ctxt {
struct svc_rdma_send_ctxt {
struct llist_node sc_node;
struct rpc_rdma_cid sc_cid;
+ struct work_struct sc_work;
+ struct svcxprt_rdma *sc_rdma;
struct ib_send_wr sc_send_wr;
struct ib_cqe sc_cqe;
struct xdr_buf sc_hdrbuf;
diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 45735f74eb86..22c39ba923d2 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -143,6 +143,7 @@ svc_rdma_send_ctxt_alloc(struct svcxprt_rdma *rdma)
svc_rdma_send_cid_init(rdma, &ctxt->sc_cid);
+ ctxt->sc_rdma = rdma;
ctxt->sc_send_wr.next = NULL;
ctxt->sc_send_wr.wr_cqe = &ctxt->sc_cqe;
ctxt->sc_send_wr.sg_list = ctxt->sc_sges;
@@ -223,15 +224,8 @@ struct svc_rdma_send_ctxt *svc_rdma_send_ctxt_get(struct svcxprt_rdma *rdma)
goto out;
}
-/**
- * svc_rdma_send_ctxt_put - Return send_ctxt to free list
- * @rdma: controlling svcxprt_rdma
- * @ctxt: object to return to the free list
- *
- * Pages left in sc_pages are DMA unmapped and released.
- */
-void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
- struct svc_rdma_send_ctxt *ctxt)
+static void svc_rdma_send_ctxt_release(struct svcxprt_rdma *rdma,
+ struct svc_rdma_send_ctxt *ctxt)
{
struct ib_device *device = rdma->sc_cm_id->device;
unsigned int i;
@@ -255,6 +249,28 @@ void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
llist_add(&ctxt->sc_node, &rdma->sc_send_ctxts);
}
+static void svc_rdma_send_ctxt_put_async(struct work_struct *work)
+{
+ struct svc_rdma_send_ctxt *ctxt;
+
+ ctxt = container_of(work, struct svc_rdma_send_ctxt, sc_work);
+ svc_rdma_send_ctxt_release(ctxt->sc_rdma, ctxt);
+}
+
+/**
+ * svc_rdma_send_ctxt_put - Return send_ctxt to free list
+ * @rdma: controlling svcxprt_rdma
+ * @ctxt: object to return to the free list
+ *
+ * Pages left in sc_pages are DMA unmapped and released.
+ */
+void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
+ struct svc_rdma_send_ctxt *ctxt)
+{
+ INIT_WORK(&ctxt->sc_work, svc_rdma_send_ctxt_put_async);
+ queue_work(svcrdma_wq, &ctxt->sc_work);
+}
+
/**
* svc_rdma_wake_send_waiters - manage Send Queue accounting
* @rdma: controlling transport
