Dave Hansen wrote:

quoted text
> On Tue, 2008-09-09 at 18:20 -0700, Balbir Singh wrote:

>> +       start = pgdat->node_start_pfn;

>> +       end = pgdat->node_start_pfn + pgdat->node_spanned_pages;

>> +       size = (end - start) * sizeof(struct page_cgroup);

>> +       printk("Allocating %lu bytes for node %d\n", size, n);

>> +       pcg_map[n] = alloc_bootmem_node(pgdat, size);

>> +       /*

>> +        * We can do smoother recovery

>> +        */

>> +       BUG_ON(!pcg_map[n]);

>> +       return 0;

>>  }

>

> This will really suck for sparse memory machines.  Imagine a machine

> with 1GB of memory at 0x0 and another 1GB of memory at 1TB up in the

> address space.

> 

I would hate to re-implement the entire sparsemem code :(

Kame did suggest making the memory controller depend on sparsemem (to hook in

from there for allocations)
> You also need to consider how it works with memory hotplug and how

quoted text
> you're going to grow it at runtime.

> 

Yes, true. This is not the final version, a very very early version that I

posted for initial comments.
> Oh, and doesn't alloc_bootmem() panic() if it fails internally anyway?

quoted text
>

> I need to look at your other approach. :)

We'll need some slab_is_available() sort of checks that sparse.c uses and also

deal with memory hotplug add and remove.
--

	Balbir

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