From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754770AbaCLQQJ (ORCPT ); Wed, 12 Mar 2014 12:16:09 -0400 Received: from mail-pb0-f50.google.com ([209.85.160.50]:39042 "EHLO mail-pb0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753198AbaCLQQH (ORCPT ); Wed, 12 Mar 2014 12:16:07 -0400 Message-ID: <53208845.5090305@kernel.dk> Date: Wed, 12 Mar 2014 10:16:05 -0600 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Felipe Franciosi , linux-kernel@vger.kernel.org CC: Sam Bradshaw Subject: Re: [PATCH 1/2] mtip32xx: Don't bounce IO requests References: <1394640348-9109-1-git-send-email-felipe@paradoxo.org> <1394640348-9109-2-git-send-email-felipe@paradoxo.org> In-Reply-To: <1394640348-9109-2-git-send-email-felipe@paradoxo.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/12/2014 10:05 AM, Felipe Franciosi wrote: > This device support 64-bit DMA and therefore no IO requests needs bouncing. > On 32-bit systems, blk_queue_bounce() will bounce all IO requests with high > mem pages. This makes performance really really bad. > > Signed-off-by: Felipe Franciosi > --- > drivers/block/mtip32xx/mtip32xx.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c > index 5160269..24c87fdb 100644 > --- a/drivers/block/mtip32xx/mtip32xx.c > +++ b/drivers/block/mtip32xx/mtip32xx.c > @@ -4082,8 +4082,6 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio) > > sg = mtip_hw_get_scatterlist(dd, &tag, unaligned); > if (likely(sg != NULL)) { > - blk_queue_bounce(queue, &bio); > - > if (unlikely((bio)->bi_vcnt > MTIP_MAX_SG)) { > dev_warn(&dd->pdev->dev, > "Maximum number of SGL entries exceeded\n"); That seems to be because the driver forgets to set the DMA capabilities. It needs a blk_queue_bounce_limit() call when it sets up the queue. -- Jens Axboe