Skip to content

K
Kernel

openeuler / Kernel
1 年多 前同步成功

通知 8
Star 0
Fork 0
K
Kernel
切换分支/标签
  1. 28 8月, 2015 1 次提交
    • R
      nd_blk: change aperture mapping from WC to WB · 67a3e8fe
      由 Ross Zwisler 提交于 
      This should result in a pretty sizeable performance gain for reads.  For
rough comparison I did some simple read testing using PMEM to compare
reads of write combining (WC) mappings vs write-back (WB).  This was
done on a random lab machine.

PMEM reads from a write combining mapping:
	# dd of=/dev/null if=/dev/pmem0 bs=4096 count=100000
	100000+0 records in
	100000+0 records out
	409600000 bytes (410 MB) copied, 9.2855 s, 44.1 MB/s

PMEM reads from a write-back mapping:
	# dd of=/dev/null if=/dev/pmem0 bs=4096 count=1000000
	1000000+0 records in
	1000000+0 records out
	4096000000 bytes (4.1 GB) copied, 3.44034 s, 1.2 GB/s

To be able to safely support a write-back aperture I needed to add
support for the "read flush" _DSM flag, as outlined in the DSM spec:

http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf

This flag tells the ND BLK driver that it needs to flush the cache lines
associated with the aperture after the aperture is moved but before any
new data is read.  This ensures that any stale cache lines from the
previous contents of the aperture will be discarded from the processor
cache, and the new data will be read properly from the DIMM.  We know
that the cache lines are clean and will be discarded without any
writeback because either a) the previous aperture operation was a read,
and we never modified the contents of the aperture, or b) the previous
aperture operation was a write and we must have written back the dirtied
contents of the aperture to the DIMM before the I/O was completed.

In order to add support for the "read flush" flag I needed to add a
generic routine to invalidate cache lines, mmio_flush_range().  This is
protected by the ARCH_HAS_MMIO_FLUSH Kconfig variable, and is currently
only supported on x86.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
      67a3e8fe
  3. 25 8月, 2015 1 次提交
    • R
      lib: scatterlist: add sg splitting function · f8bcbe62
      由 Robert Jarzmik 提交于 
      Sometimes a scatter-gather has to be split into several chunks, or sub
scatter lists. This happens for example if a scatter list will be
handled by multiple DMA channels, each one filling a part of it.

A concrete example comes with the media V4L2 API, where the scatter list
is allocated from userspace to hold an image, regardless of the
knowledge of how many DMAs will fill it :
 - in a simple RGB565 case, one DMA will pump data from the camera ISP
   to memory
 - in the trickier YUV422 case, 3 DMAs will pump data from the camera
   ISP pipes, one for pipe Y, one for pipe U and one for pipe V

For these cases, it is necessary to split the original scatter list into
multiple scatter lists, which is the purpose of this patch.

The guarantees that are required for this patch are :
 - the intersection of spans of any couple of resulting scatter lists is
   empty.
 - the union of spans of all resulting scatter lists is a subrange of
   the span of the original scatter list.
 - streaming DMA API operations (mapping, unmapping) should not happen
   both on both the resulting and the original scatter list. It's either
   the first or the later ones.
 - the caller is reponsible to call kfree() on the resulting
   scatterlists.
Signed-off-by: NRobert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: NJens Axboe <axboe@fb.com>
      f8bcbe62
  5. 21 8月, 2015 1 次提交
  7. 15 8月, 2015 1 次提交
  9. 26 6月, 2015 1 次提交
  11. 11 5月, 2015 1 次提交
    • D
      lib: add software 842 compression/decompression · 2da572c9
      由 Dan Streetman 提交于 
      Add 842-format software compression and decompression functions.
Update the MAINTAINERS 842 section to include the new files.

The 842 compression function can compress any input data into the 842
compression format.  The 842 decompression function can decompress any
standard-format 842 compressed data - specifically, either a compressed
data buffer created by the 842 software compression function, or a
compressed data buffer created by the 842 hardware compressor (located
in PowerPC coprocessors).

The 842 compressed data format is explained in the header comments.

This is used in a later patch to provide a full software 842 compression
and decompression crypto interface.
Signed-off-by: NDan Streetman <ddstreet@ieee.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
      2da572c9
  13. 17 4月, 2015 1 次提交
  15. 10 3月, 2015 1 次提交
  17. 17 2月, 2015 1 次提交
  19. 07 1月, 2015 1 次提交
  21. 23 12月, 2014 1 次提交
  23. 14 9月, 2014 1 次提交
    • L
      Make ARCH_HAS_FAST_MULTIPLIER a real config variable · 72d93104
      由 Linus Torvalds 提交于 
      It used to be an ad-hoc hack defined by the x86 version of
<asm/bitops.h> that enabled a couple of library routines to know whether
an integer multiply is faster than repeated shifts and additions.

This just makes it use the real Kconfig system instead, and makes x86
(which was the only architecture that did this) select the option.

NOTE! Even for x86, this really is kind of wrong.  If we cared, we would
probably not enable this for builds optimized for netburst (P4), where
shifts-and-adds are generally faster than multiplies.  This patch does
*not* change that kind of logic, though, it is purely a syntactic change
with no code changes.

This was triggered by the fact that we have other places that really
want to know "do I want to expand multiples by constants by hand or
not", particularly the hash generation code.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      72d93104
  25. 09 8月, 2014 1 次提交
  27. 07 8月, 2014 2 次提交
  29. 18 7月, 2014 1 次提交
  31. 05 5月, 2014 1 次提交
    • C
      lib: Export interval_tree · a88cc108
      由 Chris Wilson 提交于 
      lib/interval_tree.c provides a simple interface for an interval-tree
(an augmented red-black tree) but is only built when testing the generic
macros for building interval-trees. For drivers with modest needs,
export the simple interval-tree library as is.

v2: Lots of help from Michel Lespinasse to only compile the code
    as required:
    - make INTERVAL_TREE a config option
    - make INTERVAL_TREE_TEST select the library functions
      and sanitize the filenames & Makefile
    - prepare interval_tree for being built as a module if required
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMichel Lespinasse <walken@google.com>
[Acked for inclusion via drm/i915 by Andrew Morton.]
[danvet: switch to _GPL as per the mailing list discussion.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
      a88cc108
  33. 08 4月, 2014 1 次提交
  35. 20 3月, 2014 1 次提交
  37. 30 11月, 2013 1 次提交
  39. 15 11月, 2013 1 次提交
  41. 13 11月, 2013 1 次提交
  43. 12 11月, 2013 1 次提交
    • D
      random32: add test cases for taus113 implementation · a6a9c0f1
      由 Daniel Borkmann 提交于 
      We generated a battery of 100 test cases from GSL taus113 implemention
and compare the results from a particular seed and a particular
iteration with our implementation in the kernel. We have verified on
32 and 64 bit machines that our taus113 kernel implementation gives
same results as GSL taus113 implementation:

  [    0.147370] prandom: seed boundary self test passed
  [    0.148078] prandom: 100 self tests passed

This is a Kconfig option that is disabled on default, just like the
crc32 init selftests in order to not unnecessary slow down boot process.
We also refactored out prandom_seed_very_weak() as it's now used in
multiple places in order to reduce redundant code.

GSL code we used for generating test cases:

  int i, j;
  srand(time(NULL));
  for (i = 0; i < 100; ++i) {
    int iteration = 500 + (rand() % 500);
    gsl_rng_default_seed = rand() + 1;
    gsl_rng *r = gsl_rng_alloc(gsl_rng_taus113);
    printf("\t{ %lu, ", gsl_rng_default_seed);
    for (j = 0; j < iteration - 1; ++j)
      gsl_rng_get(r);
    printf("%u, %lu },\n", iteration, gsl_rng_get(r));
    gsl_rng_free(r);
  }

Joint work with Hannes Frederic Sowa.

Cc: Florian Weimer <fweimer@redhat.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a6a9c0f1
  45. 24 9月, 2013 1 次提交
    • D
      Add a generic associative array implementation. · 3cb98950
      由 David Howells 提交于 
      Add a generic associative array implementation that can be used as the
container for keyrings, thereby massively increasing the capacity available
whilst also speeding up searching in keyrings that contain a lot of keys.

This may also be useful in FS-Cache for tracking cookies.

Documentation is added into Documentation/associative_array.txt

Some of the properties of the implementation are:

 (1) Objects are opaque pointers.  The implementation does not care where they
     point (if anywhere) or what they point to (if anything).

     [!] NOTE: Pointers to objects _must_ be zero in the two least significant
     	       bits.

 (2) Objects do not need to contain linkage blocks for use by the array.  This
     permits an object to be located in multiple arrays simultaneously.
     Rather, the array is made up of metadata blocks that point to objects.

 (3) Objects are labelled as being one of two types (the type is a bool value).
     This information is stored in the array, but has no consequence to the
     array itself or its algorithms.

 (4) Objects require index keys to locate them within the array.

 (5) Index keys must be unique.  Inserting an object with the same key as one
     already in the array will replace the old object.

 (6) Index keys can be of any length and can be of different lengths.

 (7) Index keys should encode the length early on, before any variation due to
     length is seen.

 (8) Index keys can include a hash to scatter objects throughout the array.

 (9) The array can iterated over.  The objects will not necessarily come out in
     key order.

(10) The array can be iterated whilst it is being modified, provided the RCU
     readlock is being held by the iterator.  Note, however, under these
     circumstances, some objects may be seen more than once.  If this is a
     problem, the iterator should lock against modification.  Objects will not
     be missed, however, unless deleted.

(11) Objects in the array can be looked up by means of their index key.

(12) Objects can be looked up whilst the array is being modified, provided the
     RCU readlock is being held by the thread doing the look up.

The implementation uses a tree of 16-pointer nodes internally that are indexed
on each level by nibbles from the index key.  To improve memory efficiency,
shortcuts can be emplaced to skip over what would otherwise be a series of
single-occupancy nodes.  Further, nodes pack leaf object pointers into spare
space in the node rather than making an extra branch until as such time an
object needs to be added to a full node.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
      3cb98950
  47. 07 9月, 2013 1 次提交
  49. 03 9月, 2013 1 次提交
    • L
      lockref: implement lockless reference count updates using cmpxchg() · bc08b449
      由 Linus Torvalds 提交于 
      Instead of taking the spinlock, the lockless versions atomically check
that the lock is not taken, and do the reference count update using a
cmpxchg() loop.  This is semantically identical to doing the reference
count update protected by the lock, but avoids the "wait for lock"
contention that you get when accesses to the reference count are
contended.

Note that a "lockref" is absolutely _not_ equivalent to an atomic_t.
Even when the lockref reference counts are updated atomically with
cmpxchg, the fact that they also verify the state of the spinlock means
that the lockless updates can never happen while somebody else holds the
spinlock.

So while "lockref_put_or_lock()" looks a lot like just another name for
"atomic_dec_and_lock()", and both optimize to lockless updates, they are
fundamentally different: the decrement done by atomic_dec_and_lock() is
truly independent of any lock (as long as it doesn't decrement to zero),
so a locked region can still see the count change.

The lockref structure, in contrast, really is a *locked* reference
count.  If you hold the spinlock, the reference count will be stable and
you can modify the reference count without using atomics, because even
the lockless updates will see and respect the state of the lock.

In order to enable the cmpxchg lockless code, the architecture needs to
do three things:

 (1) Make sure that the "arch_spinlock_t" and an "unsigned int" can fit
     in an aligned u64, and have a "cmpxchg()" implementation that works
     on such a u64 data type.

 (2) define a helper function to test for a spinlock being unlocked
     ("arch_spin_value_unlocked()")

 (3) select the "ARCH_USE_CMPXCHG_LOCKREF" config variable in its
     Kconfig file.

This enables it for x86-64 (but not 32-bit, we'd need to make sure
cmpxchg() turns into the proper cmpxchg8b in order to enable it for
32-bit mode).
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      bc08b449
  51. 24 7月, 2013 1 次提交
  53. 10 7月, 2013 2 次提交
    • C
      lib: add lz4 compressor module · c72ac7a1
      由 Chanho Min 提交于 
      This patchset is for supporting LZ4 compression and the crypto API using
it.

As shown below, the size of data is a little bit bigger but compressing
speed is faster under the enabled unaligned memory access.  We can use
lz4 de/compression through crypto API as well.  Also, It will be useful
for another potential user of lz4 compression.

lz4 Compression Benchmark:
Compiler: ARM gcc 4.6.4
ARMv7, 1 GHz based board
   Kernel: linux 3.4
   Uncompressed data Size: 101 MB
         Compressed Size  compression Speed
   LZO   72.1MB		  32.1MB/s, 33.0MB/s(UA)
   LZ4   75.1MB		  30.4MB/s, 35.9MB/s(UA)
   LZ4HC 59.8MB		   2.4MB/s,  2.5MB/s(UA)
- UA: Unaligned memory Access support
- Latest patch set for LZO applied

This patch:

Add support for LZ4 compression in the Linux Kernel.  LZ4 Compression APIs
for kernel are based on LZ4 implementation by Yann Collet and were changed
for kernel coding style.

LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
LZ4 source repository : http://code.google.com/p/lz4/
svn revision : r90

Two APIs are added:

lz4_compress() support basic lz4 compression whereas lz4hc_compress()
support high compression or CPU performance get lower but compression
ratio get higher.  Also, we require the pre-allocated working memory with
the defined size and destination buffer must be allocated with the size of
lz4_compressbound.

[akpm@linux-foundation.org: make lz4_compresshcctx() static]
Signed-off-by: NChanho Min <chanho.min@lge.com>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Herbert Xu <herbert@gondor.hengli.com.au>
Cc: Yann Collet <yann.collet.73@gmail.com>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c72ac7a1
    • K
      lib: add support for LZ4-compressed kernel · e76e1fdf
      由 Kyungsik Lee 提交于 
      Add support for extracting LZ4-compressed kernel images, as well as
LZ4-compressed ramdisk images in the kernel boot process.
Signed-off-by: NKyungsik Lee <kyungsik.lee@lge.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Florian Fainelli <florian@openwrt.org>
Cc: Yann Collet <yann.collet.73@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e76e1fdf
  55. 28 6月, 2013 1 次提交
    • G
      lib: Move fonts from drivers/video/console/ to lib/fonts/ · ee89bd6b
      由 Geert Uytterhoeven 提交于 
      Several drivers need font support independent of CONFIG_VT, cfr. commit
9cbce8d7e1dae0744ca4f68d62aa7de18196b6f4, "console/font: Refactor font
support code selection logic").
Hence move the fonts and their support logic from drivers/video/console/ to
its own library directory lib/fonts/.
This also allows to limit processing of drivers/video/console/Makefile to
CONFIG_VT=y again.

[Kevin Hilman <khilman@linaro.org>: Update arch/arm/boot/compressed/Makefile]
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
      ee89bd6b
  57. 06 6月, 2013 1 次提交
  59. 20 5月, 2013 1 次提交
  61. 16 4月, 2013 1 次提交
  63. 18 1月, 2013 1 次提交
  65. 18 12月, 2012 1 次提交
  67. 08 10月, 2012 1 次提交
    • D
      X.509: Implement simple static OID registry · a77ad6ea
      由 David Howells 提交于 
      Implement a simple static OID registry that allows the mapping of an encoded
OID to an enum value for ease of use.

The OID registry index enum appears in the:

	linux/oid_registry.h

header file.  A script generates the registry from lines in the header file
that look like:

	<sp*>OID_foo,<sp*>/*<sp*>1.2.3.4<sp*>*/

The actual OID is taken to be represented by the numbers with interpolated
dots in the comment.

All other lines in the header are ignored.

The registry is queries by calling:

	OID look_up_oid(const void *data, size_t datasize);

This returns a number from the registry enum representing the OID if found or
OID__NR if not.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      a77ad6ea
  69. 31 7月, 2012 1 次提交
  71. 23 7月, 2012 1 次提交
    • D
      of/lib: Allow scripts/dtc/libfdt to be used from kernel code · ab253839
      由 David Daney 提交于 
      libfdt is part of the device tree support in scripts/dtc/libfdt.  For
some platforms that use the Device Tree, we want to be able to edit
the flattened device tree form.

We don't want to burden kernel builds that do not require it, so we
gate compilation of libfdt files with CONFIG_LIBFDT.  So if it is
needed, you need to do this in your Kconfig:

	select LIBFDT

And in the Makefile of the code using libfdt something like:

ccflags-y := -I$(src)/../../../scripts/dtc/libfdt
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: linux-kernel@vger.kernel.org
Acked-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
      ab253839
  73. 27 5月, 2012 1 次提交
    • L
      lib: add generic strnlen_user() function · a08c5356
      由 Linus Torvalds 提交于 
      This adds a new generic optimized strnlen_user() function that uses the
<asm/word-at-a-time.h> infrastructure to portably do efficient string
handling.

In many ways, strnlen is much simpler than strncpy, and in particular we
can always pre-align the words we load from memory.  That means that all
the worries about alignment etc are a non-issue, so this one can easily
be used on any architecture.  You obviously do have to do the
appropriate word-at-a-time.h macros.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a08c5356
  75. 26 5月, 2012 1 次提交