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From: Josef Bacik <jbacik@fusionio.com>
To: Kent Overstreet <kmo@daterainc.com>
Cc: <linux-kernel@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>,
	<linux-btrfs@vger.kernel.org>, <axboe@kernel.dk>,
	<hch@infradead.org>
Subject: Re: [PATCH 6/9] mtip32xx: handle arbitrary size bios
Date: Tue, 5 Nov 2013 08:49:28 -0500	[thread overview]
Message-ID: <20131105134928.GA27784@localhost.localdomain> (raw)
In-Reply-To: <1383608187-27368-7-git-send-email-kmo@daterainc.com>

On Mon, Nov 04, 2013 at 03:36:24PM -0800, Kent Overstreet wrote:
> We get a measurable performance increase by handling this in the driver when
> we're already looping over the biovec, instead of handling it separately in
> generic_make_request() (or bio_add_page() originally)
> 
> Signed-off-by: Kent Overstreet <kmo@daterainc.com>
> ---
>  drivers/block/mtip32xx/mtip32xx.c | 46 +++++++++++++--------------------------
>  1 file changed, 15 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
> index d4c669b..c5a7a96 100644
> --- a/drivers/block/mtip32xx/mtip32xx.c
> +++ b/drivers/block/mtip32xx/mtip32xx.c
> @@ -2648,24 +2648,6 @@ static void mtip_hw_submit_io(struct driver_data *dd, sector_t sector,
>  }
>  
>  /*
> - * Release a command slot.
> - *
> - * @dd  Pointer to the driver data structure.
> - * @tag Slot tag
> - *
> - * return value
> - *      None
> - */
> -static void mtip_hw_release_scatterlist(struct driver_data *dd, int tag,
> -								int unaligned)
> -{
> -	struct semaphore *sem = unaligned ? &dd->port->cmd_slot_unal :
> -							&dd->port->cmd_slot;
> -	release_slot(dd->port, tag);
> -	up(sem);
> -}
> -
> -/*
>   * Obtain a command slot and return its associated scatter list.
>   *
>   * @dd  Pointer to the driver data structure.
> @@ -4016,21 +3998,22 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio)
>  
>  	sg = mtip_hw_get_scatterlist(dd, &tag, unaligned);
>  	if (likely(sg != NULL)) {
> -		if (unlikely((bio)->bi_vcnt > MTIP_MAX_SG)) {
> -			dev_warn(&dd->pdev->dev,
> -				"Maximum number of SGL entries exceeded\n");
> -			bio_io_error(bio);
> -			mtip_hw_release_scatterlist(dd, tag, unaligned);
> -			return;
> -		}
> -
>  		/* Create the scatter list for this bio. */
>  		bio_for_each_segment(bvec, bio, iter) {
> -			sg_set_page(&sg[nents],
> -					bvec.bv_page,
> -					bvec.bv_len,
> -					bvec.bv_offset);
> -			nents++;
> +			if (unlikely(nents == MTIP_MAX_SG)) {
> +				struct bio *split = bio_clone(bio, GFP_NOIO);
> +

Need to check for memory allocation failure here.  Thanks,

Josef

  reply	other threads:[~2013-11-05 13:49 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-04 23:36 [PATCH] Block layer stuff/DIO rewrite prep for 3.14 Kent Overstreet
2013-11-04 23:36 ` [PATCH 1/9] block: Convert various code to bio_for_each_segment() Kent Overstreet
2013-11-05 13:53   ` Josef Bacik
2013-11-07 11:26   ` Jan Kara
2013-11-07 20:21     ` Kent Overstreet
2013-11-04 23:36 ` [PATCH 2/9] block: submit_bio_wait() conversions Kent Overstreet
2013-11-04 23:36 ` [PATCH 3/9] block: Move bouncing to generic_make_request() Kent Overstreet
2013-11-04 23:36 ` [PATCH 4/9] block: Make generic_make_request handle arbitrary sized bios Kent Overstreet
2013-11-04 23:56   ` [dm-devel] " Mike Christie
2013-11-05  0:55     ` Kent Overstreet
2013-11-04 23:36 ` [PATCH 5/9] block: Gut bio_add_page(), kill bio_add_pc_page() Kent Overstreet
2013-11-04 23:36 ` [PATCH 6/9] mtip32xx: handle arbitrary size bios Kent Overstreet
2013-11-05 13:49   ` Josef Bacik [this message]
2013-11-04 23:36 ` [PATCH 7/9] blk-lib.c: generic_make_request() handles large bios now Kent Overstreet
2013-11-04 23:36 ` [PATCH 8/9] bcache: " Kent Overstreet
2013-11-04 23:36 ` [PATCH 9/9] block: Add bio_get_user_pages() Kent Overstreet

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