Commit ae225fe2 authored by Chuck Lever's avatar Chuck Lever
Browse files

svcrdma: Add an async version of svc_rdma_send_ctxt_put() 



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: default avatarChuck Lever <chuck.lever@oracle.com>
parent 9c7e1a06

include/linux/sunrpc/svc_rdma.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

net/sunrpc/xprtrdma/svc_rdma_sendto.c

+25 −9
Original line number Diff line number Diff line
@@ -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;
@@ -223,14 +224,7 @@ 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,

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;
@@ -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