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Matthew Wilcox 3b3c4babd8 lib/string.c: add multibyte memset functions
Patch series "Multibyte memset variations", v4.

A relatively common idiom we're missing is a function to fill an area of
memory with a pattern which is larger than a single byte.  I first
noticed this with a zram patch which wanted to fill a page with an
'unsigned long' value.  There turn out to be quite a few places in the
kernel which can benefit from using an optimised function rather than a
loop; sometimes text size, sometimes speed, and sometimes both.  The
optimised PowerPC version (not included here) improves performance by
about 30% on POWER8 on just the raw memset_l().

Most of the extra lines of code come from the three testcases I added.

This patch (of 8):

memset16(), memset32() and memset64() are like memset(), but allow the
caller to fill the destination with a value larger than a single byte.
memset_l() and memset_p() allow the caller to use unsigned long and
pointer values respectively.

Link: http://lkml.kernel.org/r/20170720184539.31609-2-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:48 -07:00
arch mm/memory_hotplug: introduce add_pages 2017-09-08 18:26:46 -07:00
block SCSI misc on 20170907 2017-09-07 21:11:05 -07:00
certs
crypto
Documentation hmm: heterogeneous memory management documentation 2017-09-08 18:26:45 -07:00
drivers linux/kernel.h: move DIV_ROUND_DOWN_ULL() macro 2017-09-08 18:26:47 -07:00
firmware
fs fs, proc: unconditional cond_resched when reading smaps 2017-09-08 18:26:47 -07:00
include lib/string.c: add multibyte memset functions 2017-09-08 18:26:48 -07:00
init
ipc
kernel mm/device-public-memory: device memory cache coherent with CPU 2017-09-08 18:26:46 -07:00
lib lib/string.c: add multibyte memset functions 2017-09-08 18:26:48 -07:00
mm mm/mempolicy.c: remove BUG_ON() checks for VMA inside mpol_misplaced() 2017-09-08 18:26:47 -07:00
net
samples media updates for v4.14-rc1 2017-09-07 12:53:14 -07:00
scripts Merge branch 'gperf-removal' 2017-09-07 21:39:15 -07:00
security audit/stable-4.14 PR 20170907 2017-09-07 20:48:25 -07:00
sound linux/kernel.h: move DIV_ROUND_DOWN_ULL() macro 2017-09-08 18:26:47 -07:00
tools tools/testing/selftests/kcmp/kcmp_test.c: add KCMP_EPOLL_TFD testing 2017-09-08 18:26:47 -07:00
usr
virt
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS hmm: heterogeneous memory management documentation 2017-09-08 18:26:45 -07:00
Makefile
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.