Re: Dom0 ballooning: crash on guest start

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

On Fri, 29 Apr 2011 14:08:54 +0200, Christoph Egger wrote:
> balloon0: inflate 512 => inflated by 512
> for about 20 seconds until the crash happens:
>
> balloon0: inflate 512 => inflated by 512
> uvm_fault(0xffffffff80c6b220, 0xffffffff81400000, 1) -> e
> fatal page fault in supervisor mode
> trap type 6 code 0 rip ffffffff8054593d cs e030 rflags 10216 cr2
> ffffffff81400000 cpl 0 rsp f
> fffa00057ce3a40
> kernel: page fault trap, code=0
> Stopped in pid 0.58 (system) at netbsd:pmap_zero_page+0x41:     movq 
> 0(%rax,%
> rbx,8),%rbx
> pmap_zero_page() at netbsd:pmap_zero_page+0x41
> uvm_pagealloc_strat() at netbsd:uvm_pagealloc_strat+0x22d
> bpge_ctor() at netbsd:bpge_ctor+0x22
> pool_cache_get_slow() at netbsd:pool_cache_get_slow+0x1df
> pool_cache_get_paddr() at netbsd:pool_cache_get_paddr+0x1f7
> balloon_thread() at netbsd:balloon_thread+0x3bc

Okay, happens when balloon(4) has already been inflated by a good 
share.

Out of interest, having XENDEBUG_SYNC enabled in 
arch/xen/x86/x86_xpmap.c does not change anything to the result?

> BTW: The HVM guest gets 4GB RAM assigned and Xen uses
> 0x200 4KB pages, 0x3fb 2MB pages and 0x2 1GB pages for it.

Interesting. I would have imagined a higher count for 4K pages relative 
to the 2MB one.

--
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost