From: Matthew Wilcox <willy@infradead.org>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org
Subject: Re: [PATCH] mm: Introduce page_size()
Date: Mon, 31 Dec 2018 22:39:22 -0800 [thread overview]
Message-ID: <20190101063922.GE6310@bombadil.infradead.org> (raw)
In-Reply-To: <20181231230222.zq23mor2y5n67ast@kshutemo-mobl1>
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.
PAGE_MASK (and its HPAGE counterparts) always confuses me because it's
a mask which returns the upper bits rather than one which returns the
lower bits.
next prev parent reply other threads:[~2019-01-01 6:39 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-31 13:42 [PATCH] mm: Introduce page_size() Matthew Wilcox
2018-12-31 23:02 ` Kirill A. Shutemov
2019-01-01 6:39 ` Matthew Wilcox [this message]
2019-01-01 20:11 ` Zi Yan
2019-01-02 0:58 ` Matthew Wilcox
2019-01-02 1:16 ` Zi Yan
2019-01-01 3:27 ` Aneesh Kumar K.V
2019-01-01 3:27 ` Aneesh Kumar K.V
2019-01-01 6:30 ` Matthew Wilcox
2019-01-01 10:11 ` Aneesh Kumar K.V
2019-01-02 3:14 ` Matthew Wilcox
2019-01-02 11:46 ` William Kucharski
2019-01-02 13:09 ` Matthew Wilcox
2019-01-03 10:47 ` William Kucharski
2019-01-01 10:15 ` Aneesh Kumar K.V
2019-05-10 18:12 Matthew Wilcox
2019-05-13 10:56 ` Michal Hocko
2019-05-13 12:43 ` Kirill Tkhai
2019-05-14 11:53 ` William Kucharski
2019-05-22 20:03 ` Andrew Morton
2019-05-23 1:55 ` Matthew Wilcox
2019-05-23 21:33 ` Andrew Morton
2019-05-23 21:44 ` Matthew Wilcox
2019-05-24 6:34 ` Christoph Hellwig
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