On 09/23/2019 04:47 PM, Matthew Wilcox wrote:
> On Mon, Sep 23, 2019 at 11:13:45AM +0530, Anshuman Khandual wrote:
>> +#ifdef CONFIG_MEMORY_HOTPLUG
>> +static void free_hotplug_page_range(struct page *page, size_t size)
>> +{
>> + WARN_ON(!page || PageReserved(page));
>
> WARN_ON(!page) isn't terribly useful. You're going to crash on the very
> next line when you call page_address() anyway. If this line were
>
> if (WARN_ON(!page || PageReserved(page)))
> return;
>
> it would make sense, or if it were just
>
> WARN_ON(PageReserved(page))
>
> it would also make sense.
I guess WARN_ON(PageReserved(page)) should be good enough to make sure
that page being freed here was originally allocated at runtime for a
previous memory hot add operation and did not some how come from the
memblock reserved area. That was the original objective for this check.
Will change it.
>
>> + free_pages((unsigned long)page_address(page), get_order(size));
>> +}
>
