From: Jens Axboe <axboe@kernel.dk>
To: Felipe Franciosi <felipe@paradoxo.org>, linux-kernel@vger.kernel.org
Cc: Sam Bradshaw <sbradshaw@micron.com>
Subject: Re: [PATCH 1/2] mtip32xx: Don't bounce IO requests
Date: Wed, 12 Mar 2014 10:16:05 -0600 [thread overview]
Message-ID: <53208845.5090305@kernel.dk> (raw)
In-Reply-To: <1394640348-9109-2-git-send-email-felipe@paradoxo.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 <felipe@paradoxo.org>
> ---
> 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
next prev parent reply other threads:[~2014-03-12 16:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-12 16:05 [PATCH 0/2] mtip32xx: Fix arch-specific driver issues Felipe Franciosi
2014-03-12 16:05 ` [PATCH 1/2] mtip32xx: Don't bounce IO requests Felipe Franciosi
2014-03-12 16:16 ` Jens Axboe [this message]
2014-03-12 17:08 ` Felipe Franciosi
2014-03-12 17:18 ` David Vrabel
2014-03-12 17:19 ` Jens Axboe
2014-03-12 17:44 ` Felipe Franciosi
2014-03-12 16:05 ` [PATCH 2/2] mtip32xx: Unmap the DMA segments before completing the IO request Felipe Franciosi
2014-03-12 16:16 ` Jens Axboe
2014-03-12 19:04 ` Sam Bradshaw
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