Re: [PATCH] [3/5] Mark complex bitops.h inlines as __always_inline

Ingo Molnar
2009-01-07T13:19:21Z

* Hugh Dickins <hugh@veritas.com> wrote:

> Hugh Dickins noticed that released gcc versions building the kernel with
> CONFIG_OPTIMIZE_INLINING=y don't inline some of the bitops - sometimes
> generating very inefficient pageflag tests, and many instances of
> constant_test_bit().

Could you quantify that please?

We really dont want to reintroduce __always_inline just for performance /
code size reasons. If GCC messes up and makes a larger / more inefficient
kernel, GCC will be fixed. CONFIG_OPTIMIZE_INLINING is default-off, so
enable it only if it improves your kernel.

Ingo