This code is mostly from Andrew Morton and Nick Piggin; tarball downloaded
from http://ozlabs.org/~akpm/rtth.tar.gz with sha1sum
0ce679db9ec047296b5d1ff7a1dfaa03a7bef1bd

Some small modifications were necessary to the test harness to fix the
build with the current Linux source code.

I also made minor modifications to automatically test the radix-tree.c
and radix-tree.h files that are in the current source tree, as opposed
to a copied and slightly modified version.  I am sure more could be done
to tidy up the harness, as well as adding more tests.

[koct9i@gmail.com: fix compilation]
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NKonstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Impact: reduce kernel image size

Hugh Dickins noticed that older gcc versions when the kernel
is built for code size didn't inline some of the bitops.

Mark all complex x86 bitops that have more than a single
asm statement or two as always inline to avoid this problem.

Probably should be done for other architectures too.

Ingo then found a better fix that only requires
a single line change, but it unfortunately only
works on gcc 4.3.

On older gccs the original patch still makes a ~0.3% defconfig
difference with CONFIG_OPTIMIZE_INLINING=y.

With gcc 4.1 and a defconfig like build:

    61169987 1138540  883788 8139326  7c323e vmlinux-oi-with-patch
    6137043 1138540  883788 8159371  7c808b vmlinux-optimize-inlining

~20k / 0.3% difference.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch introduces the C-language equivalent of the function: unsigned long
__ffs(unsigned long word);

In include/asm-generic/bitops/__ffs.h

This code largely copied from: include/asm-sparc/bitops.h
Signed-off-by: NAkinobu Mita <mita@miraclelinux.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>