kernel/linux.git/lib/raid6/sse2.c, branch v6.12.80

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 48

2019-05-24T15:27:13+00:00

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 inc 53 temple place ste 330 boston ma 02111 1307 usa either version 2 of the license or at your option any later version incorporated herein by reference extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 13 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Kate Stewart Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170858.645641371@linutronix.de Signed-off-by: Greg Kroah-Hartman

treewide: Align function definition open/close braces

2018-03-26T09:13:09+00:00

Some functions definitions have either the initial open brace and/or the closing brace outside of column 1. Move those braces to column 1. This allows various function analyzers like gnu complexity to work properly for these modified functions. Signed-off-by: Joe Perches Acked-by: Andy Shevchenko Acked-by: Paul Moore Acked-by: Alex Deucher Acked-by: Dave Chinner Reviewed-by: Darrick J. Wong Acked-by: Alexandre Belloni Acked-by: Martin K. Petersen Acked-by: Takashi Iwai Acked-by: Mauro Carvalho Chehab Acked-by: Rafael J. Wysocki Acked-by: Nicolin Chen Acked-by: Martin K. Petersen Acked-by: Steven Rostedt (VMware) Signed-off-by: Jiri Kosina

md/raid6 algorithms: xor_syndrome() for SSE2

2015-04-21T22:00:42+00:00

The second and (last) optimized XOR syndrome calculation. This version supports right and left side optimization. All CPUs with architecture older than Haswell will benefit from it. It should be noted that SSE2 movntdq kills performance for memory areas that are read and written simultaneously in chunks smaller than cache line size. So use movdqa instead for P/Q writes in sse21 and sse22 XOR functions. Signed-off-by: Markus Stockhausen Signed-off-by: NeilBrown

md/raid6 algorithms: delta syndrome functions

2015-04-21T22:00:41+00:00

v3: s-o-b comment, explanation of performance and descision for the start/stop implementation Implementing rmw functionality for RAID6 requires optimized syndrome calculation. Up to now we can only generate a complete syndrome. The target P/Q pages are always overwritten. With this patch we provide a framework for inplace P/Q modification. In the first place simply fill those functions with NULL values. xor_syndrome() has two additional parameters: start & stop. These will indicate the first and last page that are changing during a rmw run. That makes it possible to avoid several unneccessary loops and speed up calculation. The caller needs to implement the following logic to make the functions work. 1) xor_syndrome(disks, start, stop, ...): "Remove" all data of source blocks inside P/Q between (and including) start and end. 2) modify any block with start <= block <= stop 3) xor_syndrome(disks, start, stop, ...): "Reinsert" all data of source blocks into P/Q between (and including) start and end. Pages between start and stop that won't be changed should be filled with a pointer to the kernel zero page. The reasons for not taking NULL pages are: 1) Algorithms cross the whole source data line by line. Thus avoid additional branches. 2) Having a NULL page avoids calculating the XOR P parity but still need calulation steps for the Q parity. Depending on the algorithm unrolling that might be only a difference of 2 instructions per loop. The benchmark numbers of the gen_syndrome() functions are displayed in the kernel log. Do the same for the xor_syndrome() functions. This will help to analyze performance problems and give an rough estimate how well the algorithm works. The choice of the fastest algorithm will still depend on the gen_syndrome() performance. With the start/stop page implementation the speed can vary a lot in real life. E.g. a change of page 0 & page 15 on a stripe will be harder to compute than the case where page 0 & page 1 are XOR candidates. To be not to enthusiatic about the expected speeds we will run a worse case test that simulates a change on the upper half of the stripe. So we do: 1) calculation of P/Q for the upper pages 2) continuation of Q for the lower (empty) pages Signed-off-by: Markus Stockhausen Signed-off-by: NeilBrown

lib/raid6: build proper files on corresponding arch

2012-12-13T08:51:04+00:00

sse and avx2 stuff only exist on x86 arch, and we don't need to build altivec on x86. And we can do that at lib/raid6/Makefile. Proposed-by: H. Peter Anvin Signed-off-by: Yuanhan Liu Reviewed-by: H. Peter Anvin Signed-off-by: Jim Kukunas Signed-off-by: NeilBrown

Further tidyup of raid6 naming in lib/raid6

2010-08-11T20:44:54+00:00

Rename raid6/raid6x86.h to raid6/x86.h and modify some comments. Signed-off-by: NeilBrown

Rename raid6 files now they're in a 'raid6' directory.

2010-08-10T23:19:05+00:00

Linus asks 'why "raid6" twice?'. No reason. Signed-off-by: David Woodhouse