From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dkim1.fusionio.com ([66.114.96.53]:52676 "EHLO dkim1.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755129Ab3KENtb (ORCPT ); Tue, 5 Nov 2013 08:49:31 -0500 Received: from mx1.fusionio.com (unknown [10.101.1.160]) by dkim1.fusionio.com (Postfix) with ESMTP id D45257C06B3 for ; Tue, 5 Nov 2013 06:49:30 -0700 (MST) Date: Tue, 5 Nov 2013 08:49:28 -0500 From: Josef Bacik To: Kent Overstreet CC: , , , , Subject: Re: [PATCH 6/9] mtip32xx: handle arbitrary size bios Message-ID: <20131105134928.GA27784@localhost.localdomain> References: <1383608187-27368-1-git-send-email-kmo@daterainc.com> <1383608187-27368-7-git-send-email-kmo@daterainc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: <1383608187-27368-7-git-send-email-kmo@daterainc.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: 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 > --- > 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