From: Andrew Morton <akpm@linux-foundation.org>
To: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Matthew Wilcox <willy@infradead.org>, linux-mm@kvack.org
Subject: Re: [PATCH] mm: Introduce page_size()
Date: Wed, 22 May 2019 13:03:18 -0700 [thread overview]
Message-ID: <20190522130318.4ad4dda1169e652528ecd7af@linux-foundation.org> (raw)
In-Reply-To: <eb4db346-fe5f-5b3e-1a7b-d92aee03332c@virtuozzo.com>
On Mon, 13 May 2019 15:43:08 +0300 Kirill Tkhai <ktkhai@virtuozzo.com> wrote:
> > +/*
> > + * Returns the number of bytes in this potentially compound page.
> > + * Must be called with the head page, not a tail page.
> > + */
> > +static inline unsigned long page_size(struct page *page)
> > +{
>
> Maybe we should underline commented head page limitation with VM_BUG_ON()?
VM_WARN_ONCE() if poss, please.
The code bloatage from that is likely to be distressing. Perhaps
adding an out-of-line compound_order_head_only() for this reason would
help. In which case, just uninline the whole thing...
> + return (unsigned long)PAGE_SIZE << compound_order(page);
> + }
Also, I suspect the cast here is unneeded. Architectures used to
differe in the type of PAGE_SIZE but please tell me that's been fixed
for a lomng time...
next prev parent reply other threads:[~2019-05-22 20:03 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-10 18:12 [PATCH] mm: Introduce page_size() 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 [this message]
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
-- strict thread matches above, loose matches on Subject: below --
2018-12-31 13:42 Matthew Wilcox
2018-12-31 23:02 ` Kirill A. Shutemov
2019-01-01 6:39 ` Matthew Wilcox
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
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