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 18:31:18 +0200 Message-ID: <4CC45F56.7010305@redhat.com> References: <20100911065725.GA6279@fancy-poultry.org> <4C8C9834.8060201@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 05:32 PM, dave b wrote: > I am forwarding this to the linux kernel mailing list to see if anyone > is actually interested with this bug or not. I suspect that the patch > to allow DM-CRYPT to use multiple cpus(Scale to multiple CPUs) will > remove most of the problem but *not* all of it. As I previously was > triggering the bug on a single core system. Hi, sorry for not updating the bug. We know about this. Fix was expected to be based on top of the Andi's dm-crypt per-cpu patch but unfortunately I found serious problems there (see this thread http://lkml.org/lkml/2010/10/20/215 ) 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). Milan