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Date: Wed, 26 Feb 2014 11:33:30 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v18 13/14] memory backend: fill memory
 backend ram fields
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To: Igor Mammedov <imammedo@redhat.com>, Hu Tao <hutao@cn.fujitsu.com>
Cc: lersek@redhat.com, qemu-devel@nongnu.org, Wanlong Gao <gaowanlong@cn.fujitsu.com>

Il 26/02/2014 10:10, Igor Mammedov ha scritto:
> if we assume that NUMA policies apply to every hostmem derived backend,
> then we could realize() approach used by DEVICE. i.e.
> set NUMA policies in hostmem.c:hostmemory_backend_memory_init()
>
> Add parent_complete field to ram-backend class and store there parent's
> complete pointer. Then we can do:
>
> ram_backend_memory_init(UserCreatable *uc, Error **errp) {
>     memory_region_init_ram();
>     ...
>     MEMORY_BACKEND_RAM_CLASS(uc)->parent_complete(uc, errp);
>     ...
> }
>

The problem is that some backends might not be handled the same way. 
For example, not all backends might produce a single void*/size_t pair 
for the entire region.  Think of a "composite" backend that produces a 
large memory region from two smaller ones.

Paolo