* Re: Fwd: [dm-crypt] [BUG] bad performance and system stalls when using dm-crypt [not found] ` <AANLkTikqhMbW7sWbbU_we5YE9Y9U=MPUTm553AmCyH51@mail.gmail.com> @ 2010-10-24 16:31 ` Milan Broz 2010-10-24 16:52 ` dave b 0 siblings, 1 reply; 3+ messages in thread From: Milan Broz @ 2010-10-24 16:31 UTC (permalink / raw) To: dave b; +Cc: Linux Kernel, device-mapper development 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 ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Fwd: [dm-crypt] [BUG] bad performance and system stalls when using dm-crypt 2010-10-24 16:31 ` Fwd: [dm-crypt] [BUG] bad performance and system stalls when using dm-crypt Milan Broz @ 2010-10-24 16:52 ` dave b 2010-10-24 17:05 ` Milan Broz 0 siblings, 1 reply; 3+ messages in thread From: dave b @ 2010-10-24 16:52 UTC (permalink / raw) To: Milan Broz; +Cc: Linux Kernel, device-mapper development On 25 October 2010 03:31, Milan Broz <mbroz@redhat.com> wrote: > 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). 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 ? -- There's small choice in rotten apples. -- William Shakespeare, "The Taming of the Shrew" ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Fwd: [dm-crypt] [BUG] bad performance and system stalls when using dm-crypt 2010-10-24 16:52 ` dave b @ 2010-10-24 17:05 ` Milan Broz 0 siblings, 0 replies; 3+ messages in thread From: Milan Broz @ 2010-10-24 17:05 UTC (permalink / raw) To: dave b; +Cc: Linux Kernel, device-mapper development 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 ^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-10-24 16:31 ` Fwd: [dm-crypt] [BUG] bad performance and system stalls when using dm-crypt Milan Broz
2010-10-24 16:52 ` dave b
2010-10-24 17:05 ` Milan Broz
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