Re: [bug] SLUB + mm/slab.c boot crash in -rc9

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxx> wrote:

> [...] increasing SECTION_SIZE_BITS in include/asm-x86/sparsemem.h from 
> 26 to 27 makes it go away. (i.e. we use section chunks of 128 MB 
> instead of 64 MB before) [...]

btw., here's the 'good' versus 'bad' bootup log (vanilla kernel spiced 
with a few extra stats printed out [*]):

 http://redhat.com/~mingo/misc/boot.26.log         # bad
 http://redhat.com/~mingo/misc/boot.27.log         # good

the only difference is SECTION_SIZE_BITS == 26 versus 27.

looking at the dmesg diff, there's just minimal (and expected) offset 
difference in some structure sizes. (more sparse maps use a bit more 
memory)

	Ingo

[*] in case you wonder why memory_section->map is twice its size - i 
    doubled it just to eliminate any doubts about off-by-one errors. 
    Their natural size, as returned by bootmem, was 512KB plus 16 bytes 
    (!), which seemed a bit weird. Probably a section entry came between 
    two memory map allocations?
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