summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-07 19:25:37 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-07 19:25:37 -0800
commitb5dd0c658c31b469ccff1b637e5124851e7a4a1c (patch)
treedc0b31a5aa62bb4e1fa653a4f176c2faae51f9e0 /Documentation
parent610cd4eadec4f97acd25d3108b0e50d1362b3319 (diff)
parentfe0436e10c8845aed24cad3a1c719efcd6e583eb (diff)
downloadlinux-b5dd0c658c31b469ccff1b637e5124851e7a4a1c.tar.bz2
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton: - some of the rest of MM - various misc things - dynamic-debug updates - checkpatch - some epoll speedups - autofs - rapidio - lib/, lib/lzo/ updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (83 commits) samples/mic/mpssd/mpssd.h: remove duplicate header kernel/fork.c: remove duplicated include include/linux/relay.h: fix percpu annotation in struct rchan arch/nios2/mm/fault.c: remove duplicate include unicore32: stop printing the virtual memory layout MAINTAINERS: fix GTA02 entry and mark as orphan mm: create the new vm_fault_t type arm, s390, unicore32: remove oneliner wrappers for memblock_alloc() arch: simplify several early memory allocations openrisc: simplify pte_alloc_one_kernel() sh: prefer memblock APIs returning virtual address microblaze: prefer memblock API returning virtual address powerpc: prefer memblock APIs returning virtual address lib/lzo: separate lzo-rle from lzo lib/lzo: implement run-length encoding lib/lzo: fast 8-byte copy on arm64 lib/lzo: 64-bit CTZ on arm64 lib/lzo: tidy-up ifdefs ipc/sem.c: replace kvmalloc/memset with kvzalloc and use struct_size ipc: annotate implicit fall through ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/dontdiff1
-rw-r--r--Documentation/lzo.txt39
-rw-r--r--Documentation/process/4.Coding.rst2
-rw-r--r--Documentation/translations/it_IT/process/4.Coding.rst2
4 files changed, 34 insertions, 10 deletions
diff --git a/Documentation/dontdiff b/Documentation/dontdiff
index 2228fcc8e29f..ef25a066d952 100644
--- a/Documentation/dontdiff
+++ b/Documentation/dontdiff
@@ -106,7 +106,6 @@ compile.h*
conf
config
config-*
-config_data.h*
config.mak
config.mak.autogen
conmakehash
diff --git a/Documentation/lzo.txt b/Documentation/lzo.txt
index 6fa6a93d0949..f79934225d8d 100644
--- a/Documentation/lzo.txt
+++ b/Documentation/lzo.txt
@@ -78,16 +78,34 @@ Description
is an implementation design choice independent on the algorithm or
encoding.
+Versions
+
+0: Original version
+1: LZO-RLE
+
+Version 1 of LZO implements an extension to encode runs of zeros using run
+length encoding. This improves speed for data with many zeros, which is a
+common case for zram. This modifies the bitstream in a backwards compatible way
+(v1 can correctly decompress v0 compressed data, but v0 cannot read v1 data).
+
+For maximum compatibility, both versions are available under different names
+(lzo and lzo-rle). Differences in the encoding are noted in this document with
+e.g.: version 1 only.
+
Byte sequences
==============
First byte encoding::
- 0..17 : follow regular instruction encoding, see below. It is worth
- noting that codes 16 and 17 will represent a block copy from
- the dictionary which is empty, and that they will always be
+ 0..16 : follow regular instruction encoding, see below. It is worth
+ noting that code 16 will represent a block copy from the
+ dictionary which is empty, and that it will always be
invalid at this place.
+ 17 : bitstream version. If the first byte is 17, the next byte
+ gives the bitstream version (version 1 only). If the first byte
+ is not 17, the bitstream version is 0.
+
18..21 : copy 0..3 literals
state = (byte - 17) = 0..3 [ copy <state> literals ]
skip byte
@@ -140,6 +158,11 @@ Byte sequences
state = S (copy S literals after this block)
End of stream is reached if distance == 16384
+ In version 1 only, this instruction is also used to encode a run of
+ zeros if distance = 0xbfff, i.e. H = 1 and the D bits are all 1.
+ In this case, it is followed by a fourth byte, X.
+ run length = ((X << 3) | (0 0 0 0 0 L L L)) + 4.
+
0 0 1 L L L L L (32..63)
Copy of small block within 16kB distance (preferably less than 34B)
length = 2 + (L ?: 31 + (zero_bytes * 255) + non_zero_byte)
@@ -165,7 +188,9 @@ Authors
=======
This document was written by Willy Tarreau <w@1wt.eu> on 2014/07/19 during an
- analysis of the decompression code available in Linux 3.16-rc5. The code is
- tricky, it is possible that this document contains mistakes or that a few
- corner cases were overlooked. In any case, please report any doubt, fix, or
- proposed updates to the author(s) so that the document can be updated.
+ analysis of the decompression code available in Linux 3.16-rc5, and updated
+ by Dave Rodgman <dave.rodgman@arm.com> on 2018/10/30 to introduce run-length
+ encoding. The code is tricky, it is possible that this document contains
+ mistakes or that a few corner cases were overlooked. In any case, please
+ report any doubt, fix, or proposed updates to the author(s) so that the
+ document can be updated.
diff --git a/Documentation/process/4.Coding.rst b/Documentation/process/4.Coding.rst
index cfe264889447..4b7a5ab3cec1 100644
--- a/Documentation/process/4.Coding.rst
+++ b/Documentation/process/4.Coding.rst
@@ -249,7 +249,7 @@ features; most of these are found in the "kernel hacking" submenu. Several
of these options should be turned on for any kernel used for development or
testing purposes. In particular, you should turn on:
- - ENABLE_WARN_DEPRECATED, ENABLE_MUST_CHECK, and FRAME_WARN to get an
+ - ENABLE_MUST_CHECK and FRAME_WARN to get an
extra set of warnings for problems like the use of deprecated interfaces
or ignoring an important return value from a function. The output
generated by these warnings can be verbose, but one need not worry about
diff --git a/Documentation/translations/it_IT/process/4.Coding.rst b/Documentation/translations/it_IT/process/4.Coding.rst
index c61059015e52..c05b89e616dd 100644
--- a/Documentation/translations/it_IT/process/4.Coding.rst
+++ b/Documentation/translations/it_IT/process/4.Coding.rst
@@ -264,7 +264,7 @@ La maggior parte di queste opzioni possono essere attivate per qualsiasi
kernel utilizzato per lo sviluppo o a scopo di test. In particolare dovreste
attivare:
- - ENABLE_WARN_DEPRECATED, ENABLE_MUST_CHECK, e FRAME_WARN per ottenere degli
+ - ENABLE_MUST_CHECK e FRAME_WARN per ottenere degli
avvertimenti dedicati a problemi come l'uso di interfacce deprecate o
l'ignorare un importante valore di ritorno di una funzione. Il risultato
generato da questi avvertimenti può risultare verboso, ma non bisogna