Messages in this thread | | | Date | Tue, 27 Nov 2012 20:49:02 +0800 | From | Tang Chen <> | Subject | Re: [PATCH v2 0/5] Add movablecore_map boot option |
| |
On 11/27/2012 08:09 PM, Bob Liu wrote: > On Tue, Nov 27, 2012 at 4:29 PM, Tang Chen<tangchen@cn.fujitsu.com> wrote: >> Hi Liu, >> >> This feature is used in memory hotplug. >> >> In order to implement a whole node hotplug, we need to make sure the >> node contains no kernel memory, because memory used by kernel could >> not be migrated. (Since the kernel memory is directly mapped, >> VA = PA + __PAGE_OFFSET. So the physical address could not be changed.) >> >> User could specify all the memory on a node to be movable, so that the >> node could be hot-removed. >> > > Thank you for your explanation. It's reasonable. > > But i think it's a bit duplicated with CMA, i'm not sure but maybe we > can combine it with CMA which already in mainline? > Hi Liu,
Thanks for your advice. :)
CMA is Contiguous Memory Allocator, right? What I'm trying to do is controlling where is the start of ZONE_MOVABLE of each node. Could CMA do this job ?
And also, after a short investigation, CMA seems need to base on memblock. But we need to limit memblock not to allocate memory on ZONE_MOVABLE. As a result, we need to know the ranges before memblock could be used. I'm afraid we still need an approach to get the ranges, such as a boot option, or from static ACPI tables such as SRAT/MPST.
I'm don't know much about CMA for now. So if you have any better idea, please share with us, thanks. :)
| |