From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH 00/24] ide-tape: remove pipelined mode operation Date: Sat, 1 Mar 2008 16:45:29 +0100 Message-ID: <20080301154529.GB30547@gollum.tnic> References: <1204361928-30229-1-git-send-email-petkovbb@gmail.com> <20080301095518.GW6704@kernel.dk> Reply-To: petkovbb@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from nf-out-0910.google.com ([64.233.182.190]:58986 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756508AbYCAPph (ORCPT ); Sat, 1 Mar 2008 10:45:37 -0500 Received: by nf-out-0910.google.com with SMTP id g13so2720736nfb.21 for ; Sat, 01 Mar 2008 07:45:35 -0800 (PST) Content-Disposition: inline In-Reply-To: <20080301095518.GW6704@kernel.dk> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jens Axboe Cc: bzolnier@gmail.com, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org On Sat, Mar 01, 2008 at 10:55:18AM +0100, Jens Axboe wrote: > On Sat, Mar 01 2008, Borislav Petkov wrote: > > Hi Bart, > >=20 > > here's the 1st draft of the pipeline removal series. As the diffsta= t below openly > > states it, a lot of code got removed - even more than the cleanup s= eries we did > > earlier. There are several issues that we need to address concernin= g these > > patches: > >=20 > > 1. only compile-tested since i don't have the hardware, i.e. longer= -mm brewing is > > advisable the least. > >=20 > > 2. I have left the tape->merge_stage buffer structure along with it= s > > alloc/free functions intact for now, for simplicity. The next step = would be > > to go and carefully audit the code and then remove that last piece > > too and use allocations on the stack instead. I guess we still expe= ct > > Jens's response on whether blk_{get,put}_request is the way to go h= ere. > >=20 > > Jens? >=20 > Hm, I have not seen any questions regarding this directed my way :-) > Please point me to the original question and I'll take a look at it. Hi Jens, sorry but maybe we weren't that explicit, here's a pointer to the relev= ant thread: http://www.mail-archive.com/linux-ide@vger.kernel.org/msg15541.= html. It boils down to removing the statically allocated arrays of buffers for p= c and rq structs in ide-floppy and ide-tape, and using GFP_ATOMIC stack memory i= nstead. Bart's idea was to even go a step further and even avoid allocation err= ors in out-of-mem situations by reusing requests from the request queue but wa= sn't sure whether this'll fly and wanted to run it by you... Thanks. --=20 Regards/Gru=DF, Boris.