Return-Path: Received: from mx144.netapp.com ([216.240.21.25]:26906 "EHLO mx144.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932620AbbGJT2s (ORCPT ); Fri, 10 Jul 2015 15:28:48 -0400 From: Anna Schumaker Subject: Re: [PATCH v1 02/12] xprtrdma: Raise maximum payload size to one megabyte To: Chuck Lever , , References: <20150709203242.26247.4848.stgit@manet.1015granger.net> <20150709204159.26247.44592.stgit@manet.1015granger.net> Message-ID: <55A01B56.2020107@Netapp.com> Date: Fri, 10 Jul 2015 15:21:58 -0400 MIME-Version: 1.0 In-Reply-To: <20150709204159.26247.44592.stgit@manet.1015granger.net> Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: Hi Chuck, On 07/09/2015 04:41 PM, Chuck Lever wrote: > The point of larger rsize and wsize is to reduce the per-byte cost > of memory registration and deregistration. Modern HCAs can typically > handle a megabyte or more with a single registration operation. > > Signed-off-by: Chuck Lever > --- > net/sunrpc/xprtrdma/xprt_rdma.h | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h > index f49dd8b..abee472 100644 > --- a/net/sunrpc/xprtrdma/xprt_rdma.h > +++ b/net/sunrpc/xprtrdma/xprt_rdma.h > @@ -165,8 +165,7 @@ rdmab_to_msg(struct rpcrdma_regbuf *rb) > * struct rpcrdma_buffer. N is the max number of outstanding requests. > */ > > -/* temporary static scatter/gather max */ > -#define RPCRDMA_MAX_DATA_SEGS (64) /* max scatter/gather */ > +#define RPCRDMA_MAX_DATA_SEGS ((1 * 1024 * 1024) / PAGE_SIZE) ^^^ What is the significance of the 1 here? Thanks, Anna > #define RPCRDMA_MAX_SEGS (RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = 2 */ > > struct rpcrdma_buffer; > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >