On Mon, 2012-03-12 at 22:39 -0700, Yinghai Lu wrote:
> On Mon, Mar 12, 2012 at 5:38 AM, Matt Fleming <matt.fleming@xxxxxxxxx> wrote:
>
> > Have you tested my patch? Have you hit this bug or is it just from code
> > inspection. I'm starting to feel a bit silly now because I can't see the
> > problem you're describing.
>
> from code inspection.
>
> your new init_memory_mapping() will only map mem under max_low_pfn ?
No, that's not true for x86_64, look,
for (i = 0; i < e820.nr_map; i++) {
entry = &e820.map[i];
start = entry->addr;
end = start + entry->size;
/* We've already mapped below 1MB */
if (end < (1 << 20))
continue;
if (start < (1 << 20))
start = 1 << 20;
#ifdef CONFIG_X86_32
/*
* The map is sorted, so bail once we hit a region
* that's above max_low_pfn.
*/
if (start >= max_low_pfn << PAGE_SHIFT)
break;
if (end > max_low_pfn << PAGE_SHIFT)
end = max_low_pfn << PAGE_SHIFT;
#endif
switch (entry->type) {
case E820_RAM:
case E820_RESERVED_EFI:
case E820_ACPI:
case E820_NVS:
last_pfn_mapped = __init_memory_mapping(start, end);
break;
default:
continue;
}
if (end <= max_low_pfn << PAGE_SHIFT)
max_low_pfn_mapped = last_pfn_mapped;
}
The max_low_pfn checks are only for CONFIG_X86_32 so that the behaviour
is the same as before this patch, i.e. we don't try to map above
max_low_pfn.
> and before that calling for x86_64, max_low_pfn is not updated to max_pfn yet.
>
> + max_pfn_mapped = init_memory_mapping();
>
> #ifdef CONFIG_X86_64
> if (max_pfn > max_low_pfn) {
> - max_pfn_mapped = init_memory_mapping(1UL<<32,
> - max_pfn<<PAGE_SHIFT);
> /* can we preseve max_low_pfn ?*/
> max_low_pfn = max_pfn;
> }
>
> Please do find one system with more than 4G to test the code.
I'm ordering some parts so that I can test this out.
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