Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751887AbdF1PJj (ORCPT ); Wed, 28 Jun 2017 11:09:39 -0400 Received: from mail-ua0-f174.google.com ([209.85.217.174]:36083 "EHLO mail-ua0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752554AbdF1PGN (ORCPT ); Wed, 28 Jun 2017 11:06:13 -0400 MIME-Version: 1.0 In-Reply-To: <1498663554-51272-1-git-send-email-john.garry@huawei.com> References: <1498663554-51272-1-git-send-email-john.garry@huawei.com> From: Frans Klaver Date: Wed, 28 Jun 2017 17:06:11 +0200 Message-ID: Subject: Re: [PATCH] scsi: hisi_sas: optimise DMA slot memory To: John Garry Cc: jejb@linux.vnet.ibm.com, martin.petersen@oracle.com, linuxarm@huawei.com, linux-scsi@vger.kernel.org, "linux-kernel@vger.kernel.org" , Xiaofei Tan Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 692 Lines: 19 On Wed, Jun 28, 2017 at 5:25 PM, John Garry wrote: > From: Xiaofei Tan > > Currently we allocate 3 sets of DMA memories from separate > pools for each slot. This is inefficient in terms of memory usage > (buffers are less than 1 page in size, so we lose due to alignment), > and also time spend in doing 3 allocations + de-allocations per slot, > instead of 1. > > To optimise, combine the 3 DMA buffers into a single buffer from a > single pool. > > Signed-off-by: John Garry > Signed-off-by: Xiaofei Tan I'm not sure how strictly this is done, but typically the author signs off first. Frans