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From: Igor Pylypiv <igor.pylypiv@gmail.com>
To: "Tobin C. Harding" <me@tobin.cc>
Cc: Jesse Simpson <jesse.simpson36@gmail.com>,
	kernelnewbies@kernelnewbies.org
Subject: Re: Where is PageHead defined in v5.0?
Date: Wed, 27 Mar 2019 17:23:05 -0700	[thread overview]
Message-ID: <CAPt+ddWmi+EQpX7VggpO4X2GO7SALKDtez0wAKKnMCSWUQ5eoQ@mail.gmail.com> (raw)
In-Reply-To: <20190327234935.GA11097@eros.localdomain>

On Wed, Mar 27, 2019 at 4:51 PM Tobin C. Harding <me@tobin.cc> wrote:
>
> On Wed, Mar 27, 2019 at 07:34:58PM -0500, Jesse Simpson wrote:
> > Hi Tobin,
> >
> > I took a look on my system, and I wasn't able to find where PageHead is
> > defined either. I used grep to search for it as well as vim with ctags.
> > Maybe it's hidden away in some built-in.a or binary file.
>
> Cheers Jesse, confirmation that I've not gone mad - that's a win.
>
> I'll repost this to mm-linux tomorrow if no one on here knows.
>
> thanks,
> Tobin.
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

Hi Tobin and Jesse,

Neither grep nor ctags are going to help you here :)

PageHead is implicitly defined using macros __PAGEFLAG:
        __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
        (https://elixir.bootlin.com/linux/v5.0.5/source/include/linux/page-flags.h#L517)

__PAGEFLAG defines TESTPAGEFLAG:
        (https://elixir.bootlin.com/linux/v5.0.5/source/include/linux/page-flags.h#L248)

and TESTPAGEFLAG defines PageHead:
        #define TESTPAGEFLAG(uname, lname, policy) \
        static __always_inline int Page##uname(struct page *page)
        (https://elixir.bootlin.com/linux/v5.0.5/source/include/linux/page-flags.h#L215)

See, it is simple :)

Thanks,
Igor

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  reply	other threads:[~2019-03-28  0:23 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-27 22:26 Where is PageHead defined in v5.0? Tobin C. Harding
2019-03-28  0:34 ` Jesse Simpson
2019-03-27 23:49   ` Tobin C. Harding
2019-03-28  0:23     ` Igor Pylypiv [this message]
2019-03-28  4:43       ` Tobin C. Harding
2019-03-28  5:50       ` Valdis Klētnieks
2019-03-28 20:49         ` Jesse Simpson
2019-03-28 20:56         ` Tobin C. Harding

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