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Illumos #3035 LZ4 compression support in ZFS and GRUB

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3035 LZ4 compression support in ZFS and GRUB

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Christopher Siden <csiden@delphix.com>

References:
  illumos/illumos-gate@a6f561b4ae
  https://www.illumos.org/issues/3035
  http://wiki.illumos.org/display/illumos/LZ4+Compression+In+ZFS

This patch has been slightly modified from the upstream Illumos
version to be compatible with Linux.  Due to the very limited
stack space in the kernel a lz4 workspace kmem cache is used.
Since we are using gcc we are also able to take advantage of the
gcc optimized __builtin_ctz functions.

Support for GRUB has been dropped from this patch.  That code
is available but those changes will need to made to the upstream
GRUB package.

Lastly, several hunks of dead code were dropped for clarity.  They
include the functions real_LZ4_uncompress(), LZ4_compressBound()
and the Visual Studio specific hunks wrapped in _MSC_VER.

Ported-by: Eric Dillmann <eric@jave.fr>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1217
This commit is contained in:
Eric Dillmann
2013-01-23 10:54:30 +01:00
committed by Brian Behlendorf
parent ff5b1c8065
commit 9759c60f1a
13 changed files with 1188 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
man/man8/zfs.8
+10 -1
View File
@@ -25,6 +25,7 @@
.\" Copyright (c) 2012 by Delphix. All rights reserved.
.\" Copyright (c) 2012, Joyent, Inc. All rights reserved.
.\" Copyright 2012 Nexenta Systems, Inc. All Rights Reserved.
.\" Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
.\"
.TH zfs 8 "Jan 10, 2013" "ZFS pool 28, filesystem 5" "System Administration Commands"
.SH NAME
@@ -731,7 +732,7 @@ Changing this property affects only newly-written data.
.ne 2
.mk
.na
\fBcompression\fR=\fBon\fR | \fBoff\fR | \fBlzjb\fR | \fBgzip\fR | \fBgzip-\fR\fIN\fR | \fBzle\fR
\fBcompression\fR=\fBon\fR | \fBoff\fR | \fBlzjb\fR | \fBgzip\fR | \fBgzip-\fR\fIN\fR | \fBzle\fR | \fBlz4\fR
.ad
.sp .6
.RS 4n
@@ -741,6 +742,14 @@ The \fBgzip\fR compression algorithm uses the same compression as the \fBgzip\fR
.sp
The \fBzle\fR (zero-length encoding) compression algorithm is a fast and simple algorithm to eliminate runs of zeroes.
.sp
The \fBlz4\fR compression algorithm is a high-performance replacement
for the \fBlzjb\fR algorithm. It features significantly faster
compression and decompression, as well as a moderately higher
compression ratio than \fBlzjb\fR, but can only be used on pools with
the \fBlz4_compress\fR feature set to \fIenabled\fR. See
\fBzpool-features\fR(5) for details on ZFS feature flags and the
\fBlz4_compress\fR feature.
.sp
This property can also be referred to by its shortened column name \fBcompress\fR. Changing this property affects only newly-written data.
.RE