Eric Lee / smarc-fsl-linux-kernel

13 Apr, 2020

1 commit

  • 8b0f08036   uapi: rename ext2_swab() to swab() and share globally in swab.h ... Browse Code »

    commit d5767057c9a76a29f073dad66b7fa12a90e8c748 upstream.

    ext2_swab() is defined locally in lib/find_bit.c However it is not
    specific to ext2, neither to bitmaps.

    There are many potential users of it, so rename it to just swab() and
    move to include/uapi/linux/swab.h

    ABI guarantees that size of unsigned long corresponds to BITS_PER_LONG,
    therefore drop unneeded cast.

    Link: http://lkml.kernel.org/r/20200103202846.21616-1-yury.norov@gmail.com
    Signed-off-by: Yury Norov
    Cc: Allison Randal
    Cc: Joe Perches
    Cc: Thomas Gleixner
    Cc: William Breathitt Gray
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds
    Signed-off-by: Greg Kroah-Hartman

    Yury Norov
     

31 May, 2019

1 commit

  • 2874c5fd2   treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 ... Browse Code »

    Based on 1 normalized pattern(s):

    this program is free software you can redistribute it and or modify
    it under the terms of the gnu general public license as published by
    the free software foundation either version 2 of the license or at
    your option any later version

    extracted by the scancode license scanner the SPDX license identifier

    GPL-2.0-or-later

    has been chosen to replace the boilerplate/reference in 3029 file(s).

    Signed-off-by: Thomas Gleixner
    Reviewed-by: Allison Randal
    Cc: linux-spdx@vger.kernel.org
    Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
    Signed-off-by: Greg Kroah-Hartman

    Thomas Gleixner
     

07 Feb, 2018

1 commit

  • 0ade34c37   lib: optimize cpumask_next_and() ... Browse Code »

    We've measured that we spend ~0.6% of sys cpu time in cpumask_next_and().
    It's essentially a joined iteration in search for a non-zero bit, which is
    currently implemented as a lookup join (find a nonzero bit on the lhs,
    lookup the rhs to see if it's set there).

    Implement a direct join (find a nonzero bit on the incrementally built
    join). Also add generic bitmap benchmarks in the new `test_find_bit`
    module for new function (see `find_next_and_bit` in [2] and [3] below).

    For cpumask_next_and, direct benchmarking shows that it's 1.17x to 14x
    faster with a geometric mean of 2.1 on 32 CPUs [1]. No impact on memory
    usage. Note that on Arm, the new pure-C implementation still outperforms
    the old one that uses a mix of C and asm (`find_next_bit`) [3].

    [1] Approximate benchmark code:

    ```
    unsigned long src1p[nr_cpumask_longs] = {pattern1};
    unsigned long src2p[nr_cpumask_longs] = {pattern2};
    for (/*a bunch of repetitions*/) {
    for (int n = -1; n ]
    Link: http://lkml.kernel.org/r/1512556816-28627-1-git-send-email-geert@linux-m68k.org
    Link: http://lkml.kernel.org/r/20171128131334.23491-1-courbet@google.com
    Signed-off-by: Clement Courbet
    Signed-off-by: Geert Uytterhoeven
    Cc: Yury Norov
    Cc: Geert Uytterhoeven
    Cc: Alexey Dobriyan
    Cc: Rasmus Villemoes
    Signed-off-by: Andrew Morton

    Signed-off-by: Linus Torvalds

    Clement Courbet
     

25 Feb, 2017

1 commit

  • e4afd2e55   lib/find_bit.c: micro-optimise find_next_*_bit ... Browse Code »

    This saves 32 bytes on my x86-64 build, mostly due to alignment
    considerations and sharing more code between find_next_bit and
    find_next_zero_bit, but it does save a couple of instructions.

    There's really two parts to this commit:
    - First, the first half of the test: (!nbits || start >= nbits) is
    trivially a subset of the second half, since nbits and start are both
    unsigned
    - Second, while looking at the disassembly, I noticed that GCC was
    predicting the branch taken. Since this is a failure case, it's
    clearly the less likely of the two branches, so add an unlikely() to
    override GCC's heuristics.

    [mawilcox@microsoft.com: v2]
    Link: http://lkml.kernel.org/r/1483709016-1834-1-git-send-email-mawilcox@linuxonhyperv.com
    Link: http://lkml.kernel.org/r/1483709016-1834-1-git-send-email-mawilcox@linuxonhyperv.com
    Signed-off-by: Matthew Wilcox
    Acked-by: Yury Norov
    Acked-by: Rasmus Villemoes
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Matthew Wilcox
     

17 Apr, 2015

1 commit

  • 840620a15   lib: rename lib/find_next_bit.c to lib/find_bit.c ... Browse Code »

    This file contains implementation for all find_*_bit{,_le}
    So giving it more generic name looks reasonable.

    Signed-off-by: Yury Norov
    Reviewed-by: Rasmus Villemoes
    Reviewed-by: George Spelvin
    Cc: Alexey Klimov
    Cc: David S. Miller
    Cc: Daniel Borkmann
    Cc: Hannes Frederic Sowa
    Cc: Lai Jiangshan
    Cc: Mark Salter
    Cc: AKASHI Takahiro
    Cc: Thomas Graf
    Cc: Valentin Rothberg
    Cc: Chris Wilson
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Yury Norov