From: Chuck Lever <chuck.lever@xxxxxxxxxx> Now that we have bulk page allocation and release APIs, it's more efficient to use those than it is for nfsd threads to wait for send completions. Previous patches have eliminated the calls to wait_for_completion() and complete(), in order to avoid scheduler overhead. Now release pages-under-I/O in the send completion handler using the efficient bulk release API. I've measured a 7% reduction in cumulative CPU utilization in svc_rdma_sendto(), svc_rdma_wc_send(), and svc_xprt_release(). In particular, using release_pages() instead of complete() cuts the time per svc_rdma_wc_send() call by two-thirds. This helps improve scalability because svc_rdma_wc_send() is single-threaded per connection. Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- net/sunrpc/xprtrdma/svc_rdma_sendto.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c index 1ae4236d04a3..24228f3611e8 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c @@ -236,8 +236,8 @@ void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma, struct ib_device *device = rdma->sc_cm_id->device; unsigned int i; - for (i = 0; i < ctxt->sc_page_count; ++i) - put_page(ctxt->sc_pages[i]); + if (ctxt->sc_page_count) + release_pages(ctxt->sc_pages, ctxt->sc_page_count); /* The first SGE contains the transport header, which * remains mapped until @ctxt is destroyed.
