Messages in this thread | | | Date | Wed, 12 Mar 2014 10:16:05 -0600 | From | Jens Axboe <> | Subject | Re: [PATCH 1/2] mtip32xx: Don't bounce IO requests |
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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
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