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    SubjectRe: [2.6 patch] kill __always_inline
    On Tue, Aug 31, 2004 at 04:39:14PM -0700, Andrew Morton wrote:
    > Nigel Cunningham <ncunningham@linuxmail.org> wrote:
    > >
    > > Hi.
    > >
    > > On Wed, 2004-09-01 at 08:52, Adrian Bunk wrote:
    > > > On Tue, Aug 31, 2004 at 03:36:49PM -0700, Andrew Morton wrote:
    > > > > Adrian Bunk <bunk@fs.tum.de> wrote:
    > > > > >
    > > > > > An issue that we already discussed at 2.6.8-rc2-mm2 times:
    > > > > >
    > > > > > 2.6.9-rc1 includes __always_inline which was formerly in -mm.
    > > > > > __always_inline doesn't make any sense:
    > > > > >
    > > > > > __always_inline is _exactly_ the same as __inline__, __inline and inline .
    > > > > >
    > > > > >
    > > > > > The patch below removes __always_inline again:
    > > > >
    > > > > But what happens if we later change `inline' so that it doesn't do
    > > > > the `always inline' thing?
    > > > >
    > > > > An explicit usage of __always_inline is semantically different than
    > > > > boring old `inline'.
    > >
    > > Excuse me if I'm being ignorant, but I thought always_inline was
    > > introduced because with some recent versions of gcc, inline wasn't doing
    > > the job (suspend2, which requires a working inline, was broken by it for
    > > example).
    >
    > IIRC, the compiler was generating out-of-line versions of functions in
    > every compilation unit whcih included the header file. When we the
    > developers just wanted `inline' to mean `inline, dammit'.

    `inline, dammit' is
    __attribute__((always_inline))

    The original `inline' never guarantees that the function will be
    inlined.

    Therefore, `inline' is already #define'd in the Linux kernel to always
    be __attribute__((always_inline)).

    > If that broke swsusp in some manner then the relevant swsusp functions
    > should be marked always_inline, because they have some special needs.
    >
    > > That is to say, doesn't the definition of always_inline vary
    > > with the compiler version?
    >
    > If the compiler supports attribute((always_inline)) then the kernel build
    > system will use that. If the compiler doesn't support
    > attribute((always_inline)) then we just emit `inline' from cpp and hope
    > that it works out.

    That's exactly how `inline' is already #define'd in the Linux kernel.

    And __always_inline is currently simply #define'd to `inline' ...

    cu
    Adrian

    --

    "Is there not promise of rain?" Ling Tan asked suddenly out
    of the darkness. There had been need of rain for many days.
    "Only a promise," Lao Er said.
    Pearl S. Buck - Dragon Seed

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