[Xen-devel] RE: [PATCH] Allocate vmcs pages when system booting

["Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>]

Keir Fraser wrote:
> On 12/11/2009 14:58, "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx> wrote:
> 
>>> Can you try this alternative fix please?
>> 
>> Yes, spin_debug_disable() is the first idea come into my mind, I
>> change my mind because the spin_debug is a global variable.  disable
>> spin_debug() before start_secondary means maybe we can't catch error
>> happens at that window, so I choose this method. Previously I
>> thought high-end system support cpu hotplug may not care about the
>> 64 pages :$ 
> 
> CONFIG_HOTPLUG_CPU is not a user-accessible build option. In
> fact manually
> disabling it in config.h resulted in a broken build, and now I
> basically stripped out the non-HOTPLUG_CPU code (in c/s 20431). So
> this 
> would be an
> overhead for absolutely everyone.
> 
>> Or you assume this window is quite small, and we can assume safely
>> if a error happening at this window, it will happen in other
>> timeslot in the end, sepecially this function itself don't need the
>> check? 
> 
> Exactly. The spinlock debug checking can be best effort. I did
> think about
> allowing the checks to be disabled per-cpu, but I don't think
> it's worth it.

Agree, it don't need be per-cpu.

> 
> I will check in my suggested fix, then.

Ok, I will work this way tomorrow.

Thanks
Yunhong Jiang

> 
> -- Keir
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