Re: [PATCH 4/8] v2 Allow memory block to span multiple memory sections

Nathan Fontenot
2010-09-28T18:06:49Z

On 09/27/2010 06:55 PM, Dave Hansen wrote:
> On Mon, 2010-09-27 at 14:25 -0500, Nathan Fontenot wrote:
>> +static inline int base_memory_block_id(int section_nr)
>> +{
>> + return section_nr / sections_per_block;
>> +}
> ...
>> - mutex_lock(&mem_sysfs_mutex);
>> -
>> - mem->phys_index = __section_nr(section);
>> + scn_nr = __section_nr(section);
>> + mem->phys_index = base_memory_block_id(scn_nr) * sections_per_block;
>
> I'm really regretting giving this variable such a horrid name. I suck.
>
> I think this is correct now:
>
> mem->phys_index = base_memory_block_id(scn_nr) * sections_per_block;
> mem->phys_index = section_nr / sections_per_block * sections_per_block;
> mem->phys_index = section_nr
>
> Since it gets exported to userspace this way:
>
>> +static ssize_t show_mem_start_phys_index(struct sys_device *dev,
>> struct sysdev_attribute *attr, char *buf)
>> {
>> struct memory_block *mem =
>> container_of(dev, struct memory_block, sysdev);
>> - return sprintf(buf, "%08lx\n", mem->phys_index / sections_per_block);
>> + unsigned long phys_index;
>> +
>> + phys_index = mem->start_phys_index / sections_per_block;
>> + return sprintf(buf, "%08lx\n", phys_index);
>> +}
>
> The only other thing I'd say is that we need to put phys_index out of
> its misery and call it what it is now: a section number. I think it's
> OK to call them "start/end_section_nr", at least inside the kernel. I
> intentionally used "phys_index" terminology in sysfs so that we _could_
> eventually do this stuff and break the relationship between sections and
> the sysfs dirs, but I think keeping the terminology around inside the
> kernel is confusing now.

Yes, it took me a couple o looks to get the phys_index <-> section number
correlation. I think changing the kernel names to start/end_section_number
is a good idea.

-Nathan

>
> -- Dave
>