linux-toradex.git/include/linux/bitmap.h, branch v4.14-rc3

bitmap: introduce BITMAP_FROM_U64()

2017-09-09T01:26:49+00:00

The macro is the compile-time analogue of bitmap_from_u64() with the same
purpose: convert the 64-bit number to the properly ordered pair of 32-bit
parts, suitable for filling the bitmap in 32-bit BE environment.

Use it to make test_bitmap_parselist() correct for 32-bit BE ABIs.

Tested on BE mips/qemu.

[akpm@linux-foundation.org: tweak code comment]
Link: http://lkml.kernel.org/r/20170810172916.24144-1-ynorov@caviumnetworks.com
Signed-off-by: Yury Norov 
Cc: Noam Camus 
Cc: Rasmus Villemoes 
Cc: Matthew Wilcox 
Cc: Mauro Carvalho Chehab 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bitmap: use memcmp optimisation in more situations

2017-07-10T23:32:34+00:00

Commit 7dd968163f7c ("bitmap: bitmap_equal memcmp optimization") was
rather more restrictive than necessary; we can use memcmp() to implement
bitmap_equal() as long as the number of bits can be proved to be a
multiple of 8.  And architectures other than s390 may be able to make
good use of this optimisation.

[arnd@arndb.de: fix build: add a memcmp() declaration]
  Link: http://lkml.kernel.org/r/20170630153908.3439707-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170628153221.11322-5-willy@infradead.org
Signed-off-by: Matthew Wilcox 
Signed-off-by: Arnd Bergmann 
Acked-by: Rasmus Villemoes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

include/linux/bitmap.h: turn bitmap_set and bitmap_clear into memset when possible

2017-07-10T23:32:34+00:00

Several callers have constant 'start' and an 'nbits' that is a multiple
of 8, so we can turn them into calls to memset.  We don't need the
entirety of 'start' and 'nbits' to be constant, we just need to know
whether they're divisible by 8.

Link: http://lkml.kernel.org/r/20170628153221.11322-4-willy@infradead.org
Signed-off-by: Matthew Wilcox 
Acked-by: Rasmus Villemoes 
Cc: Martin Schwidefsky 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bitmap: optimise bitmap_set and bitmap_clear of a single bit

2017-07-10T23:32:34+00:00

We have eight users calling bitmap_clear for a single bit and seventeen
calling bitmap_set for a single bit.  Rather than fix all of them to
call __clear_bit or __set_bit, turn bitmap_clear and bitmap_set into
inline functions and make this special case efficient.

Link: http://lkml.kernel.org/r/20170628153221.11322-3-willy@infradead.org
Signed-off-by: Matthew Wilcox 
Acked-by: Rasmus Villemoes 
Cc: Martin Schwidefsky 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bitmap.h, perf/core: Fix the mask in perf_output_sample_regs()

2016-08-18T08:44:20+00:00

When decoding the perf_regs mask in perf_output_sample_regs(),
we loop through the mask using find_first_bit and find_next_bit functions.

While the exisiting code works fine in most of the case, the logic
is broken for big-endian 32-bit kernels.

When reading a u64 mask using (u32 *)(&val)[0], find_*_bit() assumes
that it gets the lower 32 bits of u64, but instead it gets the upper
32 bits - which is wrong.

The fix is to swap the words of the u64 to handle this case.
This is _not_ a regular endianness swap.

Suggested-by: Yury Norov 
Signed-off-by: Madhavan Srinivasan 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Yury Norov 
Cc: Alexander Shishkin 
Cc: Arnaldo Carvalho de Melo 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Michael Ellerman 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1471426568-31051-2-git-send-email-maddy@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar

include/linux/bitmap.h: cleanup

2016-08-04T12:50:07+00:00

Remove two unneeded `else's.

Cc: David Hildenbrand 
Cc: Martin Schwidefsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bitmap: bitmap_equal memcmp optimization

2016-06-13T13:58:21+00:00

The bitmap_equal function has optimized code for small bitmaps with less
than BITS_PER_LONG bits. For larger bitmaps the out-of-line function
__bitmap_equal is called.

For a constant number of bits divisible by BITS_PER_LONG the memcmp
function can be used. For s390 gcc knows how to optimize this function,
memcmp calls with up to 256 bytes / 2048 bits are translated into a
single instruction.

Reviewed-by: David Hildenbrand 
Signed-off-by: Martin Schwidefsky

lib/bitmap.c: conversion routines to/from u32 array

2016-02-20T03:54:09+00:00

Aimed at transferring bitmaps to/from user-space in a 32/64-bit agnostic
way.

Tested:
  unit tests (next patch) on qemu i386, x86_64, ppc, ppc64 BE and LE,
  ARM.

Signed-off-by: David Decotigny 
Reviewed-by: Ben Hutchings 
Signed-off-by: David S. Miller

linux/bitmap: Force inlining of bitmap weight functions

2015-08-05T07:38:08+00:00

With this config:

  http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os

gcc-4.7.2 generates many copies of these tiny functions:

	bitmap_weight (55 copies):
	55                      push   %rbp
	48 89 e5                mov    %rsp,%rbp
	e8 3f 3a 8b 00          callq  __bitmap_weight
	5d                      pop    %rbp
	c3                      retq

	hweight_long (23 copies):
	55                      push   %rbp
	e8 b5 65 8e 00          callq  __sw_hweight64
	48 89 e5                mov    %rsp,%rbp
	5d                      pop    %rbp
	c3                      retq

See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122

This patch fixes this via s/inline/__always_inline/

While at it, replaced two "__inline__" with usual "inline"
(the rest of the source file uses the latter).

	    text     data      bss       dec  filename
	86971357 17195880 36659200 140826437  vmlinux.before
	86971120 17195912 36659200 140826232  vmlinux

Signed-off-by: Denys Vlasenko 
Cc: Andrew Morton 
Cc: David Rientjes 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Thomas Graf 
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1438697716-28121-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar

lib/bitmap.c: bitmap_[empty,full]: remove code duplication

2015-04-17T13:03:56+00:00

bitmap_empty() has its own implementation.  But it's clearly as simple as:

	find_first_bit(src, nbits) == nbits

The same is true for 'bitmap_full'.

Signed-off-by: Yury Norov 
Cc: George Spelvin 
Cc: Alexey Klimov 
Cc: Rasmus Villemoes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds