Messages in this thread | | | Date | Tue, 25 Aug 2009 23:40:11 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [patch] x86: 2.6.31-rc7 crash due to buggy flat_phys_pkg_id |
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[Ravikiran G Thirumalai - Tue, Aug 25, 2009 at 12:20:55PM -0700] | On Tue, Aug 25, 2009 at 10:31:30PM +0400, Cyrill Gorcunov wrote: | >[Ingo Molnar - Tue, Aug 25, 2009 at 08:15:00PM +0200] | >| | > | >I'm definitely not APIC expert but since I was partially involved | >letme turn in. | > | >Original commit which causes problem for vSMP seems to be due | >to cpu_has_apic bit turned off (ie due to being manually disabled | >or acpi table broken) so further read apic id will return plain | >zero (we're talking about 64 bits now). So frnakly I don't understand | >what is wrong with Ravikiran's patch. In case of apic disabled | >initial apic value will be used anyway (which is latched but | >actually may be changed, but it's not our case). | > | | Exactly my thinking. I hoped the patch I posted solves both cases -- | does not depend on local apic id for the "fix crash on certain UP configs" | case in the commit here: | | http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=2759c3287de27266e06f1f4e82cbd2d65f6a044c | | And fixes vsmp too. | | >Or perhaps there is an issue in srat numa nodes numbering? | > | | Don't think so, local apic id has been used for for 'flat' and 'cluster' | apic (which was used prior to 'flat') for atleast 15 major releases. | | Cyrill/Yinghai, can you test and confirm if the patch attached does not | regress the 'UP crash case' mentioned in | commit 2759c3287de27266e06f1f4e82cbd2d65f6a044c please? | | --- |
I would like to but I can;t. I don;t even know where were we hanging at this crash case. I was only reading commit changelog and since it was said about "not apic bit set" I thought about disabled apic case.
Personally I like much more quirk Yinghai posted which leaves phys id function _bared_ and simple as it should be :)
And since it's too late before kernel release -- introducing read apic back seems to be dangerous I suppose: there are a number of configs which could be having side effect. At moment they are tested _with_ Yinghai patch and only vSMP is issued. Though the problem need to be investigated more closely. But I'm not knowing that much in this area.
-- Cyrill
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