Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754325Ab3GTWJD (ORCPT ); Sat, 20 Jul 2013 18:09:03 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:45221 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753597Ab3GTWJA (ORCPT ); Sat, 20 Jul 2013 18:09:00 -0400 Message-ID: <1374358463.7397.1124.camel@haakon3.risingtidesystems.com> Subject: Re: [PATCH RESEND 0/1] AHCI: Optimize interrupt processing From: "Nicholas A. Bellinger" To: Mike Christie Cc: James Bottomley , Jens Axboe , Alexander Gordeev , Tejun Heo , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, Jeff Garzik , linux-scsi Date: Sat, 20 Jul 2013 15:14:23 -0700 In-Reply-To: <51EAA33C.9010405@fusionio.com> References: <20130711102630.GA11133@dhcp-26-207.brq.redhat.com> <1373583637.7397.370.camel@haakon3.risingtidesystems.com> <20130712074559.GA8727@dhcp-26-207.brq.redhat.com> <1373692812.7397.625.camel@haakon3.risingtidesystems.com> <20130716183207.GA6402@dhcp-26-207.brq.redhat.com> <1374010683.7397.880.camel@haakon3.risingtidesystems.com> <20130717161909.GB21468@dhcp-26-207.brq.redhat.com> <1374173515.7397.948.camel@haakon3.risingtidesystems.com> <51E83E32.9050306@cs.wisc.edu> <1374193399.7397.973.camel@haakon3.risingtidesystems.com> <20130719003034.GG28005@kernel.dk> <1374195825.7397.997.camel@haakon3.risingtidesystems.com> <1374215660.7397.1041.camel@haakon3.risingtidesystems.com> <1374248000.2266.20.camel@dabdike> <1374267684.7397.1058.camel@haakon3.risingtidesystems.com> <1374296162.7397.1098.camel@haakon3.risingtidesystems.com> <51EAA33C.9010405@fusionio.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3968 Lines: 108 On Sat, 2013-07-20 at 09:48 -0500, Mike Christie wrote: > On 07/19/2013 11:56 PM, Nicholas A. Bellinger wrote: > > On Fri, 2013-07-19 at 14:01 -0700, Nicholas A. Bellinger wrote: > >> On Fri, 2013-07-19 at 08:33 -0700, James Bottomley wrote: > >> > >> Indeed. Looking into the bio_copy_kern() breakage next.. > >> > > > > OK, after further investigation the root cause is a actually a missing > > bio->bio_end_io() -> bio_copy_kern_endio() -> bio_put() from the > > blk_end_sync_rq() callback path that scsi-mq REQ_TYPE_BLOCK_PC is > > currently using. > > > > Including the following patch into the scsi-mq working branch now, and > > reverting the libata dma_alignment=0x03 hack. > > > > Alexander, care to give this a try..? > > > > --nab > > > > diff --git a/block/blk-exec.c b/block/blk-exec.c > > index 0761c89..70303d2 100644 > > --- a/block/blk-exec.c > > +++ b/block/blk-exec.c > > @@ -25,7 +25,10 @@ static void blk_end_sync_rq(struct request *rq, int error) > > struct completion *waiting = rq->end_io_data; > > > > rq->end_io_data = NULL; > > - if (!rq->q->mq_ops) { > > + if (rq->q->mq_ops) { > > + if (rq->bio) > > + bio_endio(rq->bio, error); > > + } else { > > __blk_put_request(rq->q, rq); > > } > > > > > This does not handle requests with multiple bios, and for the mq stye > passthrough insertion completions you actually want to call > blk_mq_finish_request in scsi_execute. Same for all the other > passthrough code in your scsi mq tree. That is your root bug. Instead of > doing that though I think we want to have the block layer free the bios > like before. > > For the non mq calls, blk_end_request type of calls will complete the > bios when blk_finish_request is called from that path. It will then call > the rq end_io callback. > > I think the blk mq code assumes if the end_io callack is set that the > end_io function will do the bio cleanup. See __blk_mq_end_io. Also see > how blk_mq_execute_rq calls blk_mq_finish_request for an example of how > rq passthrough execution and cleanup is being done in the mq paths. > > Now with the scsi mq changes, when blk_execute_rq_nowait calls > blk_mq_insert_request it calls it with a old non mq style of end io > function that does not complete the bios. > > What about the attached only compile tested patch. The patch has the mq > block code work like the non mq code for bio cleanups. > > OK, so with your blk-mq patch in place to always call blk_mq_finish_request() in blk_mq_complete_request() regardless of rq->end_io, the preceding scsi_mq_end_request() can now simply call blk_mq_end_io() for both BLOCK_RQ and FS request types. diff --git a/drivers/scsi/scsi-mq.c b/drivers/scsi/scsi-mq.c index 81b2633..f1d4789 100644 --- a/drivers/scsi/scsi-mq.c +++ b/drivers/scsi/scsi-mq.c @@ -93,19 +93,7 @@ struct scsi_cmnd *scsi_mq_end_request(struct scsi_cmnd *sc, int error, #endif //FIXME: Add proper blk_mq_end_io residual bytes + requeue - if (rq->end_io) { -#if 0 - printk("scsi_mq_end_request: Calling rq->end_io BLOCK_PC for" - " CDB: 0x%02x\n", sc->cmnd[0]); -#endif - rq->end_io(rq, error); - } else { -#if 0 - printk("scsi_mq_end_request: Calling blk_mq_end_io for CDB: 0x%02x\n", - sc->cmnd[0]); -#endif - blk_mq_end_io(rq, error); - } + blk_mq_end_io(rq, error); //FIXME: Need to do equiv of scsi_next_command to kick hctx..? return NULL; Thanks for fixing up that bit of ugliness. ;) Jens, care to review+include Mike's change into your working branch..? --nab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/