On 1 Jan 2019, at 1:39, Matthew Wilcox wrote:
> On Tue, Jan 01, 2019 at 02:02:22AM +0300, Kirill A. Shutemov wrote:
>> On Mon, Dec 31, 2018 at 05:42:23AM -0800, Matthew Wilcox wrote:
>>> It's unnecessarily hard to find out the size of a potentially huge page.
>>> Replace 'PAGE_SIZE << compound_order(page)' with page_size(page).
>>
>> Good idea.
>>
>> Should we add page_mask() and page_shift() too?
>
> I'm not opposed to that at all. I also have a patch to add compound_nr():
>
> +/* Returns the number of pages in this potentially compound page. */
> +static inline unsigned long compound_nr(struct page *page)
> +{
> + return 1UL << compound_order(page);
> +}
>
> I just haven't sent it yet ;-) It should, perhaps, be called page_count()
> or nr_pages() or something. That covers most of the remaining users of
> compound_order() which look awkward.
We already have hpage_nr_pages() to show the number of pages. Why do we need
another one?
--
Best Regards,
Yan Zi
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