On 10/14/2013 12:34 PM, Yinghai Lu wrote:
>
> The points for parsing SRAT early instead of Yanfei/Tang v7:
> 1. We just reached one unified path to setup page tables for 32bit,
> 64bit and xen or non xen after several years. We should not have add
> another path for system
> that support hotplug.
>
> 2. also we should avoid adding "movable_nodes" command line.
>
> 3. debug mapping 4k, and it is working all the way, why breaking it even for
> memory hotplug path?
>
> 4. numa_meminfo now is static structure.
> we have no reason that we can not parse SRAT etc to fill that struct.
>
> 5. for device tree, i assume that we could do same like srat parsing to find
> out
> numa to fill the numa_meminfo early. or with help of BRK.
>
> 6. in the long run, We should rework our NUMA booting:
> a. boot system with boot numa nodes early only.
> b. in later init stage or user space, init other nodes
> RAM/CPU/PCI...in parallel.
> that will reduce boot time for 8 sockets/32 sockets dramatically.
>
> We will need to parse srat table early so could avoid init memory for
> non-boot nodes.
>
I really like the long-term plan (and, I might want to add, the above
writeup.)
However, I don't understand how we can avoid #2, given that it is
fundamentally a sysadmin-driven tradeoff between performance and
reliability.
-hpa
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