Re: [PATCH v1 2/4] memblock: update initialization of reserved pages

David Hildenbrand
2021-04-20T15:19:02Z

On 20.04.21 17:03, Mike Rapoport wrote:
> On Tue, Apr 20, 2021 at 03:56:28PM +0200, David Hildenbrand wrote:
>> On 20.04.21 11:09, Mike Rapoport wrote:
>>> From: Mike Rapoport <rppt@linux.ibm.com>
>>>
>>> The struct pages representing a reserved memory region are initialized
>>> using reserve_bootmem_range() function. This function is called for each
>>> reserved region just before the memory is freed from memblock to the buddy
>>> page allocator.
>>>
>>> The struct pages for MEMBLOCK_NOMAP regions are kept with the default
>>> values set by the memory map initialization which makes it necessary to
>>> have a special treatment for such pages in pfn_valid() and
>>> pfn_valid_within().
>>
>> Just a general question while thinking about it:
>>
>> Would we right now initialize the memmap of these pages already via
>> memmap_init_zone()->memmap_init_range()? (IOW, not marking the
>> PageReserved?)
>
> Yep. These pages are part of memblock.memory so they are initialized in
> memmap_init_zone()->memmap_init_range() to the default values.
>

So instead of fully initializing them again, we mostly would only have
to set PageReserved(). Not sure how big that memory usually is -- IOW,
if we really care about optimizing the double-init.

--
Thanks,

David / dhildenb