[PATCH 0/8] De-couple sysfs memory directories from memory sections
dave at linux.vnet.ibm.com
Thu Sep 23 04:58:49 EST 2010
On Wed, 2010-09-22 at 13:40 -0500, Nathan Fontenot wrote:
> On 09/22/2010 10:20 AM, Dave Hansen wrote:
> > and phys_index's calculation needs to be:
> > mem->start_phys_index * SECTION_SIZE / memory_block_size_bytes()
> I'm not sure if I follow where you suggest using this formula. Is this
> instead of what is used now, the base_memory_block_id() calculation?
> If so, then I'm not sure it would work. The formula used in base_memory_block_id()
> is done because the memory sections are not guaranteed to be added to the
> memory block starting with the first section of the block.
> If you meant somewhere else let me know.
My point was just that if we change the "block_size_bytes" contents,
then we have to scale down the "memoryXXXX/phys_index" by that same
It *used* to be in numbers of SECTION_SIZE units, and I think it still
- mem->start_phys_index = __section_nr(section);
+ mem->start_phys_index = base_memory_block_id(__section_nr(section));
+ mem->end_phys_index = mem->start_phys_index + sections_per_block - 1;
but now it needs to be changed to be in memory_block_size_bytes() units,
*NOT* SECTION_SIZE units.
Let's say we have a system with 4 16MB sections starting at 0x0.
Before, we would have:
Now, we change memory_block_size_bytes() to be 32MB instead. We reduce
the number of sections in half, and I think the right thing to get is:
I think, with your code (as it stands in these patches, no fixes) that
we'd instead get this:
Without consulting "end_phys_index" (which isn't and can't be a part of
the existing ABI), we'd think that we have two 16MB banks instead of
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