From mboxrd@z Thu Jan 1 00:00:00 1970 From: Milan Broz Subject: Re: Fwd: [dm-crypt] [BUG] bad performance and system stalls when using dm-crypt Date: Sun, 24 Oct 2010 19:05:55 +0200 Message-ID: <4CC46773.2000606@redhat.com> References: <20100911065725.GA6279@fancy-poultry.org> <4C8C9834.8060201@redhat.com> <4CC45F56.7010305@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: dave b Cc: Linux Kernel , device-mapper development List-Id: dm-devel.ids On 10/24/2010 06:52 PM, dave b wrote: >> So there are now several known situations when dm-crypt doesn't >> perform as expected (another problem just appeared when using CFQ, >> (because dm(-crypt) lost the issuing process reference) >> see http://lkml.org/lkml/2010/10/24/59). > > Thank for you replying ^ ^ > I was aware with the problems and I am following Andi's dm-crypt > per-cpu patch (I haven't applied or tested it). However, I didn't know > about http://lkml.org/lkml/2010/10/24/59 --> > So this may well be the root of the problem! > Also, won't http://lkml.org/lkml/2010/10/24/59 need to be altered > (again) to work with Andi's patch ? CFQ related problem should be solved - probably device-mapper core have to provide some help. (It is not only about dm-crypt, lot of situations when IO is submitted from different internal process. The proposed patch is not the proper and complete way how to solve it.) For the per-cpu patch - I am waiting for replay, apparently some additional work there is needed. But I would like to solve it ASAP. Milan