On Wed, Mar 12, 2014 at 4:16 PM, Jens Axboe <[email protected]> wrote: > > 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 <[email protected]> >> --- >> 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 >
Hmm... I see what you are saying. David, would you like to comment? Thanks, Felipe p.s. resending as GMail was naughty and sent my previous reply in HTML. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
