Re: Panic on 8-node system in memblock_virt_alloc_try_nid()

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 23 Jan 2014 22:57:08 -0800 Yinghai Lu <yinghai@kernel.org> wrote:

> On Thu, Jan 23, 2014 at 10:38 PM, Santosh Shilimkar
> <santosh.shilimkar@ti.com> wrote:
> > Yinghai,
> >
> > On Friday 24 January 2014 12:55 AM, Yinghai Lu wrote:
> >> On Thu, Jan 23, 2014 at 2:49 PM, Dave Hansen <dave.hansen@intel.com> wrote:
> >>> > Linus's current tree doesn't boot on an 8-node/1TB NUMA system that I
> >>> > have.  Its reboots are *LONG*, so I haven't fully bisected it, but it's
> >>> > down to a just a few commits, most of which are changes to the memblock
> >>> > code.  Since the panic is in the memblock code, it looks like a
> >>> > no-brainer.  It's almost certainly the code from Santosh or Grygorii
> >>> > that's triggering this.
> >>> >
> >>> > Config and good/bad dmesg with memblock=debug are here:
> >>> >
> >>> >         http://sr71.net/~dave/intel/3.13/
> >>> >
> >>> > Please let me know if you need it bisected further than this.
> >> Please check attached patch, and it should fix the problem.
> >>
> >
> > [...]
> >
> >>
> >> Subject: [PATCH] x86: Fix numa with reverting wrong memblock setting.
> >>
> >> Dave reported Numa on x86 is broken on system with 1T memory.
> >>
> >> It turns out
> >> | commit 5b6e529521d35e1bcaa0fe43456d1bbb335cae5d
> >> | Author: Santosh Shilimkar <santosh.shilimkar@ti.com>
> >> | Date:   Tue Jan 21 15:50:03 2014 -0800
> >> |
> >> |    x86: memblock: set current limit to max low memory address
> >>
> >> set limit to low wrongly.
> >>
> >> max_low_pfn_mapped is different from max_pfn_mapped.
> >> max_low_pfn_mapped is always under 4G.
> >>
> >> That will memblock_alloc_nid all go under 4G.
> >>
> >> Revert that offending patch.
> >>
> >> Reported-by: Dave Hansen <dave.hansen@intel.com>
> >> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> >>
> >>
> > This mostly will fix the $subject issue but the regression
> > reported by Andrew [1] will surface with the revert. Its clear
> > now that even though commit fixed the issue, it wasn't the fix.
> >
> > Would be great if you can have a look at the thread.
> 
> >> [1] http://lkml.indiana.edu/hypermail/linux/kernel/1312.1/03770.html
> 
> Andrew,
> 
> Did you bisect which patch in that 23 patchset cause your system have problem?
> 

Yes - it was caused by the patch which that email was replying to. 
"[PATCH v3 13/23] mm/lib/swiotlb: Use memblock apis for earlymemory
allocations".

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