From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [BUG] 2.6.29-rc6-2450cf in scsi_lib.c (was: Large amount of scsi-sgpool)objects Date: Thu, 5 Mar 2009 12:10:40 +0100 Message-ID: <20090305111040.GZ11787@kernel.dk> References: <20090305101436.GV11787@kernel.dk> <20090305192737I.fujita.tomonori@lab.ntt.co.jp> <20090305103023.GW11787@kernel.dk> <20090305194118A.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from brick.kernel.dk ([93.163.65.50]:55398 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751173AbZCELKm (ORCPT ); Thu, 5 Mar 2009 06:10:42 -0500 Content-Disposition: inline In-Reply-To: <20090305194118A.fujita.tomonori@lab.ntt.co.jp> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: FUJITA Tomonori Cc: tglx@linutronix.de, James.Bottomley@HansenPartnership.com, jengelh@medozas.de, bharrosh@panasas.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org On Thu, Mar 05 2009, FUJITA Tomonori wrote: > On Thu, 5 Mar 2009 11:30:24 +0100 > Jens Axboe wrote: > > > > > While merging that, I think we can do better than this. Essentially we > > > > just need to have __blk_recalc_rq_segments() track the back bio as well, > > > > then we don't have to pass in a pointer for segment sizes. > > > > > > > > Totally untested, comments welcome... > > > > > > Yeah, I think that updating bi_seg_front_size and bi_seg_back_size at > > > one place, __blk_recalc_rq_segments, is better. I thought about the > > > same way. But we are already in -rc7 and this must go into mainline > > > now. So I chose a less-intrusive way (similar to what we have done in > > > the past). > > > > > > As you know, the merging code is really complicated and we could > > > overlook stuff easily. ;) It might be better to simplify the merging > > > code a bit. > > > > If someone (Ingo?) is willing to test the last variant, I'd much rather > > add that. It does simplify it (imho), and it kills 23 lines while only > > adding 9. But a quick response would be nice, then I can ask Linus to > > pull it later today. > > I prefer to keep your change for 2.6.30 but if you want to push it > now, it's fine by me. I honestly can't see much of a difference in change complexity, so I don't see much point in putting one fix in 2.6.29 and then doing another for 2.6.30... > Ingo, you can quickly hit this bug without the patch? > > I've not hit this bug while I've been performing intensive I/Os for > the last three hours. And I thought that Thomas took two hours to hit > this. So maybe it's too early to give 'Tested-by'. With > max_segment_size decreased, we might hit this easier. Yep, that may help. I haven't seen this thread until I was cc'ed on it, so I haven't even read up on the generic problem yet... -- Jens Axboe