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Filename Latest commit message Latest commit date
Alexey Dobriyan c311c79799 cpumask: make "nr_cpumask_bits" unsigned
Bit searching functions accept "unsigned long" indices but
"nr_cpumask_bits" is "int" which is signed, so inevitable sign
extensions occur on x86_64.  Those MOVSX are #1 MOVSX bloat by number of
uses across whole kernel.

Change "nr_cpumask_bits" to unsigned, this number can't be negative
after all.  It allows to do implicit zero-extension on x86_64 without
MOVSX.

Change signed comparisons into unsigned comparisons where necessary.

Other uses looks fine because it is either argument passed to a function
or comparison is already unsigned.

Net win on allyesconfig type of kernel: ~2.8 KB (!)

	add/remove: 0/0 grow/shrink: 8/725 up/down: 93/-2926 (-2833)
	function                                     old     new   delta
	xen_exit_mmap                                691     735     +44
	qstat_read                                   426     440     +14
	__cpufreq_cooling_register                  1678    1687      +9
	trace_rb_cpu_prepare                         447     455      +8
	vermagic                                      54      60      +6
	nfp_driver_version                            54      60      +6
	rcu_torture_stats_print                     1147    1151      +4
	find_next_push_cpu                           267     269      +2
	xen_irq_resume                               961     960      -1
				...
	init_vp_index                                946     906     -40
	od_set_powersave_bias                        328     281     -47
	power_cpu_exit                               193     139     -54
	arch_show_interrupts                        3538    3484     -54
	select_idle_sibling                         1558    1471     -87
	Total: Before=158358910, After=158356077, chg -0.00%

Same arguments apply to "nr_cpu_ids" but I haven't yet found enough
courage to delve into this issue (and proper fix may require new type
"cpu_t" which is whole separate story).

Link: http://lkml.kernel.org/r/20170309205322.GA1728@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08 17:15:11 -07:00
arch cpumask: make "nr_cpumask_bits" unsigned 2017-05-08 17:15:11 -07:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-05-06 11:25:08 -07:00
certs
crypto
Documentation docs: complete bumping minimal GNU Make version to 3.81 2017-05-06 18:49:09 -07:00
drivers drivers/misc/c2port/c2port-duramar2150.c: checking for NULL instead of IS_ERR() 2017-05-08 17:15:10 -07:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs reiserfs: use designated initializers 2017-05-08 17:15:11 -07:00
include cpumask: make "nr_cpumask_bits" unsigned 2017-05-08 17:15:11 -07:00
init initramfs: avoid "label at end of compound statement" error 2017-05-06 10:27:13 -07:00
ipc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2017-05-05 11:08:43 -07:00
kernel fork: free vmapped stacks in cache when cpus are offline 2017-05-08 17:15:11 -07:00
lib checkpatch: add ability to find bad uses of vsprintf %p<foo> extensions 2017-05-08 17:15:10 -07:00
mm mm, compaction: finish whole pageblock to reduce fragmentation 2017-05-08 17:15:10 -07:00
net Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2017-05-05 11:08:43 -07:00
samples
scripts checkpatch: improve the SUSPECT_CODE_INDENT test 2017-05-08 17:15:11 -07:00
security
sound
tools libnvdimm for 4.12 2017-05-05 18:49:20 -07:00
usr
virt arm64 updates for 4.12: 2017-05-05 12:11:37 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap Staging/IIO patches for 4.12-rc1 2017-05-05 18:16:23 -07:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Staging/IIO patches for 4.12-rc1 2017-05-05 18:16:23 -07:00
Makefile make help: add tools help target 2017-05-08 17:15:10 -07:00
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.