From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756757Ab3LBUDO (ORCPT ); Mon, 2 Dec 2013 15:03:14 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:39149 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753505Ab3LBTRy (ORCPT ); Mon, 2 Dec 2013 14:17:54 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vu Pham , Nicholas Bellinger Subject: [PATCH 3.12 093/212] iser-target: Avoid using FRMR for single dma entry requests Date: Mon, 2 Dec 2013 11:14:44 -0800 Message-Id: <20131202191257.897405691@linuxfoundation.org> X-Mailer: git-send-email 1.8.4.3.gca3854a In-Reply-To: <20131202191248.517975703@linuxfoundation.org> References: <20131202191248.517975703@linuxfoundation.org> User-Agent: quilt/0.60-8.1.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vu Pham commit f01b9f73392b48c6cda7c2c66594c73137c776da upstream. This patch changes isert_reg_rdma_frwr() to not use FRMR for single dma entry requests from small I/Os, in order to avoid the associated memory registration overhead. Using DMA MR is sufficient here for the single dma entry requests, and addresses a >= v3.12 performance regression. Signed-off-by: Vu Pham Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/ulp/isert/ib_isert.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) --- a/drivers/infiniband/ulp/isert/ib_isert.c +++ b/drivers/infiniband/ulp/isert/ib_isert.c @@ -2259,18 +2259,26 @@ isert_reg_rdma_frwr(struct iscsi_conn *c data_len = min(data_left, rdma_write_max); wr->cur_rdma_length = data_len; - spin_lock_irqsave(&isert_conn->conn_lock, flags); - fr_desc = list_first_entry(&isert_conn->conn_frwr_pool, - struct fast_reg_descriptor, list); - list_del(&fr_desc->list); - spin_unlock_irqrestore(&isert_conn->conn_lock, flags); - wr->fr_desc = fr_desc; + /* if there is a single dma entry, dma mr is sufficient */ + if (count == 1) { + ib_sge->addr = ib_sg_dma_address(ib_dev, &sg_start[0]); + ib_sge->length = ib_sg_dma_len(ib_dev, &sg_start[0]); + ib_sge->lkey = isert_conn->conn_mr->lkey; + wr->fr_desc = NULL; + } else { + spin_lock_irqsave(&isert_conn->conn_lock, flags); + fr_desc = list_first_entry(&isert_conn->conn_frwr_pool, + struct fast_reg_descriptor, list); + list_del(&fr_desc->list); + spin_unlock_irqrestore(&isert_conn->conn_lock, flags); + wr->fr_desc = fr_desc; - ret = isert_fast_reg_mr(fr_desc, isert_cmd, isert_conn, - ib_sge, offset, data_len); - if (ret) { - list_add_tail(&fr_desc->list, &isert_conn->conn_frwr_pool); - goto unmap_sg; + ret = isert_fast_reg_mr(fr_desc, isert_cmd, isert_conn, + ib_sge, offset, data_len); + if (ret) { + list_add_tail(&fr_desc->list, &isert_conn->conn_frwr_pool); + goto unmap_sg; + } } return 0;