Commit Graph

100 Commits

Author SHA1 Message Date
Alexey Dobriyan 4de373a12f cpumask: make cpumask_size() return "unsigned int"
CPUmasks are never big enough to warrant 64-bit code.

Space savings:

	add/remove: 0/0 grow/shrink: 1/4 up/down: 3/-17 (-14)
	Function                                     old     new   delta
	sched_init_numa                             1530    1533      +3
	compat_sys_sched_setaffinity                 160     159      -1
	sys_sched_getaffinity                        197     195      -2
	sys_sched_setaffinity                        183     176      -7
	compat_sys_sched_getaffinity                 179     172      -7

Link: http://lkml.kernel.org/r/20171204165531.GA8221@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06 18:32:45 -08:00
Ingo Molnar 8a103df440 Merge branch 'linus' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-08 10:17:15 +01:00
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Rakib Mullick e22cdc3fc5 sched/isolcpus: Fix "isolcpus=" boot parameter handling when !CONFIG_CPUMASK_OFFSTACK
cpulist_parse() uses nr_cpumask_bits as a limit to parse the
passed buffer from kernel commandline. What nr_cpumask_bits
represents varies depending upon the CONFIG_CPUMASK_OFFSTACK option:

 - If CONFIG_CPUMASK_OFFSTACK=n, then nr_cpumask_bits is the same as
   NR_CPUS, which might not represent the # of CPUs that really exist
   (default 64). So, there's a chance of a gap between nr_cpu_ids
   and NR_CPUS, which ultimately lead towards invalid cpulist_parse()
   operation. For example, if isolcpus=9 is passed on an 8 cpu
   system (CONFIG_CPUMASK_OFFSTACK=n) it doesn't show the error
   that it's supposed to.

This patch fixes this bug by finding the last CPU of the passed
isolcpus= list and checking it against nr_cpu_ids.

It also fixes the error message where the nr_cpu_ids should be
nr_cpu_ids-1, since CPU numbering starts from 0.

Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adobriyan@gmail.com
Cc: akpm@linux-foundation.org
Cc: longman@redhat.com
Cc: mka@chromium.org
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/20171023130154.9050-1-rakib.mullick@gmail.com
[ Enhanced the changelog and the kernel message. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

 include/linux/cpumask.h |   16 ++++++++++++++++
 kernel/sched/topology.c |    4 ++--
 2 files changed, 18 insertions(+), 2 deletions(-)
2017-10-24 11:47:25 +02:00
Alexey Dobriyan f22ef333c3 cpumask: make cpumask_next() out-of-line
Every for_each_XXX_cpu() invocation calls cpumask_next() which is an
inline function:

	static inline unsigned int cpumask_next(int n, const struct cpumask *srcp)
	{
	        /* -1 is a legal arg here. */
	        if (n != -1)
	                cpumask_check(n);
	        return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1);
	}

However!

find_next_bit() is regular out-of-line function which means "nr_cpu_ids"
load and increment happen at the caller resulting in a lot of bloat

x86_64 defconfig:
	add/remove: 3/0 grow/shrink: 8/373 up/down: 155/-5668 (-5513)
x86_64 allyesconfig-ish:
	add/remove: 3/1 grow/shrink: 57/634 up/down: 3515/-28177 (-24662) !!!

Some archs redefine find_next_bit() but it is OK:

	m68k		inline but SMP is not supported
	arm		out-of-line
	unicore32	out-of-line

Function call will happen anyway, so move load and increment into callee.

Link: http://lkml.kernel.org/r/20170824230010.GA1593@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:51 -07:00
Alexey Dobriyan 9b130ad5bb treewide: make "nr_cpu_ids" unsigned
First, number of CPUs can't be negative number.

Second, different signnnedness leads to suboptimal code in the following
cases:

1)
	kmalloc(nr_cpu_ids * sizeof(X));

"int" has to be sign extended to size_t.

2)
	while (loff_t *pos < nr_cpu_ids)

MOVSXD is 1 byte longed than the same MOV.

Other cases exist as well. Basically compiler is told that nr_cpu_ids
can't be negative which can't be deduced if it is "int".

Code savings on allyesconfig kernel: -3KB

	add/remove: 0/0 grow/shrink: 25/264 up/down: 261/-3631 (-3370)
	function                                     old     new   delta
	coretemp_cpu_online                          450     512     +62
	rcu_init_one                                1234    1272     +38
	pci_device_probe                             374     399     +25

				...

	pgdat_reclaimable_pages                      628     556     -72
	select_fallback_rq                           446     369     -77
	task_numa_find_cpu                          1923    1807    -116

Link: http://lkml.kernel.org/r/20170819114959.GA30580@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
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
Peter Zijlstra 6c8557bdb2 smp, cpumask: Use non-atomic cpumask_{set,clear}_cpu()
The cpumasks in smp_call_function_many() are private and not subject
to concurrency, atomic bitops are pointless and expensive.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-23 10:01:32 +02:00
Peter Zijlstra c743f0a5c5 sched/fair, cpumask: Export for_each_cpu_wrap()
More users for for_each_cpu_wrap() have appeared. Promote the construct
to generic cpumask interface.

The implementation is slightly modified to reduce arguments.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Lauro Ramos Venancio <lvenanci@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: lwang@redhat.com
Link: http://lkml.kernel.org/r/20170414122005.o35me2h5nowqkxbv@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-15 10:15:23 +02:00
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
Matthias Kaehlcke f7e30f01a9 cpumask: Add helper cpumask_available()
With CONFIG_CPUMASK_OFFSTACK=y cpumask_var_t is a struct cpumask
pointer, otherwise a struct cpumask array with a single element.

Some code dealing with cpumasks needs to validate that a cpumask_var_t
is not a NULL pointer when CONFIG_CPUMASK_OFFSTACK=y. This is typically
done by performing the check always, regardless of the underlying type
of cpumask_var_t. This works in both cases, however clang raises a
warning like this when CONFIG_CPUMASK_OFFSTACK=n:

kernel/irq/manage.c:839:28: error: address of array
'desc->irq_common_data.affinity' will always evaluate to 'true'
[-Werror,-Wpointer-bool-conversion]

Add the inline helper cpumask_available() which only performs the
pointer check if CONFIG_CPUMASK_OFFSTACK=y.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Cc: Grant Grundler <grundler@chromium.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Hackmann <ghackmann@google.com>
Cc: Michael Davidson <md@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20170412182030.83657-1-mka@chromium.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-14 19:50:47 +02:00
Linus Torvalds 20dcfe1b7d Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
 "Nothing exciting, just the usual pile of fixes, updates and cleanups:

   - A bunch of clocksource driver updates

   - Removal of CONFIG_TIMER_STATS and the related /proc file

   - More posix timer slim down work

   - A scalability enhancement in the tick broadcast code

   - Math cleanups"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  hrtimer: Catch invalid clockids again
  math64, tile: Fix build failure
  clocksource/drivers/arm_arch_timer:: Mark cyclecounter __ro_after_init
  timerfd: Protect the might cancel mechanism proper
  timer_list: Remove useless cast when printing
  time: Remove CONFIG_TIMER_STATS
  clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101
  clocksource/drivers/arm_arch_timer: Introduce generic errata handling infrastructure
  clocksource/drivers/arm_arch_timer: Remove fsl-a008585 parameter
  clocksource/drivers/arm_arch_timer: Add dt binding for hisilicon-161010101 erratum
  clocksource/drivers/ostm: Add renesas-ostm timer driver
  clocksource/drivers/ostm: Document renesas-ostm timer DT bindings
  clocksource/drivers/tcb_clksrc: Use 32 bit tcb as sched_clock
  clocksource/drivers/gemini: Add driver for the Cortina Gemini
  clocksource: add DT bindings for Cortina Gemini
  clockevents: Add a clkevt-of mechanism like clksrc-of
  tick/broadcast: Reduce lock cacheline contention
  timers: Omit POSIX timer stuff from task_struct when disabled
  x86/timer: Make delay() work during early bootup
  delay: Add explanation of udelay() inaccuracy
  ...
2017-02-20 10:06:32 -08:00
Tejun Heo 4d59b6ccf0 cpumask: use nr_cpumask_bits for parsing functions
Commit 513e3d2d11 ("cpumask: always use nr_cpu_ids in formatting and
parsing functions") converted both cpumask printing and parsing
functions to use nr_cpu_ids instead of nr_cpumask_bits.  While this was
okay for the printing functions as it just picked one of the two output
formats that we were alternating between depending on a kernel config,
doing the same for parsing wasn't okay.

nr_cpumask_bits can be either nr_cpu_ids or NR_CPUS.  We can always use
nr_cpu_ids but that is a variable while NR_CPUS is a constant, so it can
be more efficient to use NR_CPUS when we can get away with it.
Converting the printing functions to nr_cpu_ids makes sense because it
affects how the masks get presented to userspace and doesn't break
anything; however, using nr_cpu_ids for parsing functions can
incorrectly leave the higher bits uninitialized while reading in these
masks from userland.  As all testing and comparison functions use
nr_cpumask_bits which can be larger than nr_cpu_ids, the parsed cpumasks
can erroneously yield false negative results.

This made the taskstats interface incorrectly return -EINVAL even when
the inputs were correct.

Fix it by restoring the parse functions to use nr_cpumask_bits instead
of nr_cpu_ids.

Link: http://lkml.kernel.org/r/20170206182442.GB31078@htj.duckdns.org
Fixes: 513e3d2d11 ("cpumask: always use nr_cpu_ids in formatting and parsing functions")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Martin Steigerwald <martin.steigerwald@teamix.de>
Debugged-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-08 15:41:43 -08:00
Waiman Long 668802c257 tick/broadcast: Reduce lock cacheline contention
It was observed that on an Intel x86 system without the ARAT (Always
running APIC timer) feature and with fairly large number of CPUs as
well as CPUs coming in and out of intel_idle frequently, the lock
contention on the tick_broadcast_lock can become significant.

To reduce contention, the lock is put into its own cacheline and all
the cpumask_var_t variables are put into the __read_mostly section.

Running the SP benchmark of the NAS Parallel Benchmarks on a 4-socket
16-core 32-thread Nehalam system, the performance number improved
from 3353.94 Mop/s to 3469.31 Mop/s when this patch was applied on
a 4.9.6 kernel.  This is a 3.4% improvement.

Signed-off-by: Waiman Long <longman@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1485799063-20857-1-git-send-email-longman@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-02-04 08:54:46 +01:00
Thomas Gleixner 427d77a323 x86/smpboot: Prevent false positive out of bounds cpumask access warning
prefill_possible_map() reinitializes the cpu_possible_map by setting the
possible cpu bits and clearing all other bits up to NR_CPUS.

This is technically always correct because cpu_possible_map is statically
allocated and sized NR_CPUS. With CPUMASK_OFFSTACK and DEBUG_PER_CPU_MAPS
enabled the bounds check of cpu masks happens on nr_cpu_ids. nr_cpu_ids is
initialized to NR_CPUS and only limited after the set/clear bit loops have
been executed. 

But if the system was booted with "nr_cpus=N" on the command line, where N
is < NR_CPUS then nr_cpu_ids is limited in the parameter parsing function
before prefill_possible_map() is invoked. As a consequence the cpumask
bounds check triggers when clearing the bits past nr_cpu_ids.

Add a helper which allows to reset cpu_possible_map w/o the bounds check
and then set only the possible bits which are well inside bounds.

Reported-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: 0x7f454c46@gmail.com
Cc: Jan Beulich <JBeulich@novell.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1612131836050.3415@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-15 11:32:31 +01:00
Geliang Tang b06fb41533 cpumask: fix code comment
Fix code comment for cpumask_parse().

Link: http://lkml.kernel.org/r/71aae2c60ae5dae0cf554199ce6aea8f88c69347.1465380581.git.geliangtang@gmail.com
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:24 -04:00
Peter Zijlstra (Intel) e9d867a67f sched: Allow per-cpu kernel threads to run on online && !active
In order to enable symmetric hotplug, we must mirror the online &&
!active state of cpu-down on the cpu-up side.

However, to retain sanity, limit this state to per-cpu kthreads.

Aside from the change to set_cpus_allowed_ptr(), which allow moving
the per-cpu kthreads on, the other critical piece is the cpu selection
for pinned tasks in select_task_rq(). This avoids dropping into
select_fallback_rq().

select_fallback_rq() cannot be allowed to select !active cpus because
its used to migrate user tasks away. And we do not want to move user
tasks onto cpus that are in transition.

Requested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160301152303.GV6356@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-06 14:58:22 +02:00
Eric Biggers 95f27356e4 cpumask: remove incorrect information from comment
Since commit cdfdef75e7 ("cpumask: only allocate nr_cpumask_bits."),
this comment above cpumask_size() is no longer relevant.

Signed-off-by: Eric Biggers <ebiggers3@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Rasmus Villemoes 9425676a36 kernel/cpu.c: make set_cpu_* static inlines
Almost all callers of the set_cpu_* functions pass an explicit true or
false.  Making them static inline thus replaces the function calls with a
simple set_bit/clear_bit, saving some .text.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 17:09:18 -08:00
Rasmus Villemoes 5aec01b834 kernel/cpu.c: eliminate cpu_*_mask
Replace the variables cpu_possible_mask, cpu_online_mask, cpu_present_mask
and cpu_active_mask with macros expanding to expressions of the same type
and value, eliminating some indirection.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 17:09:18 -08:00
Rasmus Villemoes 4b804c85dc kernel/cpu.c: export __cpu_*_mask
Exporting the cpumasks __cpu_possible_mask and friends will allow us to
remove the extra indirection through the cpu_*_mask variables.  It will
also allow the set_cpu_* functions to become static inlines, which will
give a .text reduction.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 17:09:18 -08:00
Rusty Russell f36963c9d3 cpumask_set_cpu_local_first => cpumask_local_spread, lament
da91309e0a (cpumask: Utility function to set n'th cpu...) created a
genuinely weird function.  I never saw it before, it went through DaveM.
(He only does this to make us other maintainers feel better about our own
mistakes.)

cpumask_set_cpu_local_first's purpose is say "I need to spread things
across N online cpus, choose the ones on this numa node first"; you call
it in a loop.

It can fail.  One of the two callers ignores this, the other aborts and
fails the device open.

It can fail in two ways: allocating the off-stack cpumask, or through a
convoluted codepath which AFAICT can only occur if cpu_online_mask
changes.  Which shouldn't happen, because if cpu_online_mask can change
while you call this, it could return a now-offline cpu anyway.

It contains a nonsensical test "!cpumask_of_node(numa_node)".  This was
drawn to my attention by Geert, who said this causes a warning on Sparc.
It sets a single bit in a cpumask instead of returning a cpu number,
because that's what the callers want.

It could be made more efficient by passing the previous cpu rather than
an index, but that would be more invasive to the callers.

Fixes: da91309e0a
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (then rebased)
Tested-by: Amir Vadai <amirv@mellanox.com>
Acked-by: Amir Vadai <amirv@mellanox.com>
Acked-by: David S. Miller <davem@davemloft.net>
2015-05-28 11:05:20 +09:30
Rusty Russell 1527781d22 cpumask: resurrect CPU_MASK_CPU0
We removed it in 2f0f267ea0 (cpumask: remove deprecated functions.),
but grep shows it still used by MIPS, and not unreasonably.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-04-16 12:33:51 +09:30
Rasmus Villemoes 3bbf7f4624 linux/cpumask.h: add typechecking to cpumask_test_cpu
The Subtlety (1) referred to vanished with 6ba2ef7baa ("cpumask:
Move deprecated functions to end of header."). That used to mention
some suboptimal code generation by a, by now, rather ancient gcc. With
gcc 4.7, I don't see any change in the generated code by making it a
static inline, so let's add type checking and get rid of the ghost
reference.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-03-31 13:55:31 +10:30
Rusty Russell cdfdef75e7 cpumask: only allocate nr_cpumask_bits.
Now we'll find out the hard way if anyone has CPUMASK_OFFSTACK and is
returning these or assigning them.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-03-10 13:54:42 +10:30
Rusty Russell 2f0f267ea0 cpumask: remove deprecated functions.
Using these functions with offstack cpus is unsafe.  They use all NR_CPUS
bits, unstead of nr_cpumask_bits.

In particular, lustre (in staging) used cpus_ and that caused a bug.

Reported-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-03-10 13:54:41 +10:30
Rusty Russell 9941a383df CPU_MASK_ALL/CPU_MASK_NONE: remove from deprecated region.
They're used to initialize various static fields, though static
cpumasks should generally be avoided.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-03-05 15:27:06 +10:30
Tejun Heo 46385326cc bitmap, cpumask, nodemask: remove dedicated formatting functions
Now that all bitmap formatting usages have been converted to
'%*pb[l]', the separate formatting functions are unnecessary.  The
following functions are removed.

* bitmap_scn[list]printf()
* cpumask_scnprintf(), cpulist_scnprintf()
* [__]nodemask_scnprintf(), [__]nodelist_scnprintf()
* seq_bitmap[_list](), seq_cpumask[_list](), seq_nodemask[_list]()
* seq_buf_bitmask()

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:39 -08:00
Tejun Heo f1bbc032e4 cpumask, nodemask: implement cpumask/nodemask_pr_args()
printf family of functions can now format bitmaps using '%*pb[l]' and
all cpumask and nodemask formatting will be converted to use it.  To
ease printing these masks with '%*pb[l]' which require two params -
the number of bits and the actual bitmap, this patch implement
cpumask_pr_args() and nodemask_pr_args() which can be used to provide
arguments for '%*pb[l]'

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:36 -08:00
Tejun Heo 513e3d2d11 cpumask: always use nr_cpu_ids in formatting and parsing functions
bitmap implements two variants of scnprintf functions to format a bitmap
into a string and cpumask and nodemask wrap them to provide equivalent
interfaces.  The scnprintf family of functions require a string buffer as
an output target which complicates code paths which just want to print out
the mask through printk for informational or debug purposes as they have
to worry about how large the buffer should be and whether it's too large
to allocate on stack.

Neither cpumask or nodemask provides a guildeline on how large the target
buffer should be forcing users come up with their own solutions - some
allocate an arbitrarily sized buffer which is small enough to allocate on
stack but may be too short in corner cases, other come up with a custom
upper limit calculation considering the output format, some allocate the
buffer dynamically while one resorted to using lock to synchronize access
to a static buffer.

This is an artificial problem which is being solved repeatedly for no
benefit.  In a lot of cases, the output area already exists and can be
targeted directly making the intermediate buffer unnecessary.  This
patchset teaches printf family of functions how to format bitmaps and
replace the dedicated formatting functions with it.

Pointer formatting is extended to cover bitmap formatting.  It uses the
field width for the number of bits instead of precision.  The format used
is '%*pb[l]', with the optional trailing 'l' specifying list format
instead of hex masks.  For more details, please see 0002.

This patch (of 31):

Currently, the formatting and parsing functions in cpumask.h use
nr_cpumask_bits like other cpumask functions; however, nr_cpumask_bits
is either NR_CPUS or nr_cpu_ids depending on CONFIG_CPUMASK_OFFSTACK.
This leads to inconsistent behaviors.

With CONFIG_NR_CPUS=512 and !CONFIG_CPUMASK_OFFSTACK

  # cat /sys/devices/virtual/net/lo/queues/rx-0/rps_cpus
  00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000
  # cat /proc/self/status | grep Cpus_allowed:
  Cpus_allowed:   f

With CONFIG_NR_CPUS=1024 and CONFIG_CPUMASK_OFFSTACK (fedora default)

  # cat /sys/devices/virtual/net/lo/queues/rx-0/rps_cpus
  0
  # cat /proc/self/status | grep Cpus_allowed:
  Cpus_allowed:   f

Note that /proc/self/status is always using nr_cpu_ids regardless of
config.  This is because seq cpumask formattings functions always use
nr_cpu_ids.

Given that the same output fields may switch between the two forms,
converging on nr_cpu_ids always isn't too likely to surprise userland.
This patch updates the formatting and parsing functions in cpumask.h
to always use nr_cpu_ids.  There's no point in dealing with CPUs which
aren't even possible on the machine.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:36 -08:00
Rasmus Villemoes f5ac1f5520 linux/cpumask.h: update bitmap wrappers to take unsigned int
Since the various bitmap_* functions now take an unsigned int as nbits
parameter, it makes sense to also update the various wrappers, even though
they're marked as obsolete.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-12 18:54:14 -08:00
Sudeep Holla 5aaba36318 cpumask: factor out show_cpumap into separate helper function
Many sysfs *_show function use cpu{list,mask}_scnprintf to copy cpumap
to the buffer aligned to PAGE_SIZE, append '\n' and '\0' to return null
terminated buffer with newline.

This patch creates a new helper function cpumap_print_to_pagebuf in
cpumask.h using newly added bitmap_print_to_pagebuf and consolidates
most of those sysfs functions using the new helper function.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: x86@kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-07 11:45:00 -08:00
Christoph Lameter 4ba2968420 percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
__get_cpu_var can paper over differences in the definitions of
cpumask_var_t and either use the address of the cpumask variable
directly or perform a fetch of the address of the struct cpumask
allocated elsewhere. This is important particularly when using per cpu
cpumask_var_t declarations because in one case we have an offset into
a per cpu area to handle and in the other case we need to fetch a
pointer from the offset.

This patch introduces a new macro

this_cpu_cpumask_var_ptr()

that is defined where cpumask_var_t is defined and performs the proper
actions. All use cases where __get_cpu_var is used with cpumask_var_t
are converted to the use of this_cpu_cpumask_var_ptr().

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-28 08:58:57 -04:00
Linus Torvalds f9da455b93 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:

 1) Seccomp BPF filters can now be JIT'd, from Alexei Starovoitov.

 2) Multiqueue support in xen-netback and xen-netfront, from Andrew J
    Benniston.

 3) Allow tweaking of aggregation settings in cdc_ncm driver, from Bjørn
    Mork.

 4) BPF now has a "random" opcode, from Chema Gonzalez.

 5) Add more BPF documentation and improve test framework, from Daniel
    Borkmann.

 6) Support TCP fastopen over ipv6, from Daniel Lee.

 7) Add software TSO helper functions and use them to support software
    TSO in mvneta and mv643xx_eth drivers.  From Ezequiel Garcia.

 8) Support software TSO in fec driver too, from Nimrod Andy.

 9) Add Broadcom SYSTEMPORT driver, from Florian Fainelli.

10) Handle broadcasts more gracefully over macvlan when there are large
    numbers of interfaces configured, from Herbert Xu.

11) Allow more control over fwmark used for non-socket based responses,
    from Lorenzo Colitti.

12) Do TCP congestion window limiting based upon measurements, from Neal
    Cardwell.

13) Support busy polling in SCTP, from Neal Horman.

14) Allow RSS key to be configured via ethtool, from Venkata Duvvuru.

15) Bridge promisc mode handling improvements from Vlad Yasevich.

16) Don't use inetpeer entries to implement ID generation any more, it
    performs poorly, from Eric Dumazet.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1522 commits)
  rtnetlink: fix userspace API breakage for iproute2 < v3.9.0
  tcp: fixing TLP's FIN recovery
  net: fec: Add software TSO support
  net: fec: Add Scatter/gather support
  net: fec: Increase buffer descriptor entry number
  net: fec: Factorize feature setting
  net: fec: Enable IP header hardware checksum
  net: fec: Factorize the .xmit transmit function
  bridge: fix compile error when compiling without IPv6 support
  bridge: fix smatch warning / potential null pointer dereference
  via-rhine: fix full-duplex with autoneg disable
  bnx2x: Enlarge the dorq threshold for VFs
  bnx2x: Check for UNDI in uncommon branch
  bnx2x: Fix 1G-baseT link
  bnx2x: Fix link for KR with swapped polarity lane
  sctp: Fix sk_ack_backlog wrap-around problem
  net/core: Add VF link state control policy
  net/fsl: xgmac_mdio is dependent on OF_MDIO
  net/fsl: Make xgmac_mdio read error message useful
  net_sched: drr: warn when qdisc is not work conserving
  ...
2014-06-12 14:27:40 -07:00
Amir Vadai da91309e0a cpumask: Utility function to set n'th cpu - local cpu first
This function sets the n'th cpu - local cpu's first.
For example: in a 16 cores server with even cpu's local, will get the
following values:
cpumask_set_cpu_local_first(0, numa, cpumask) => cpu 0 is set
cpumask_set_cpu_local_first(1, numa, cpumask) => cpu 2 is set
...
cpumask_set_cpu_local_first(7, numa, cpumask) => cpu 14 is set
cpumask_set_cpu_local_first(8, numa, cpumask) => cpu 1 is set
cpumask_set_cpu_local_first(9, numa, cpumask) => cpu 3 is set
...
cpumask_set_cpu_local_first(15, numa, cpumask) => cpu 15 is set

Curently this function will be used by multi queue networking devices to
calculate the irq affinity mask, such that as many local cpu's as
possible will be utilized to handle the mq device irq's.

Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-11 14:58:16 -07:00
David S. Miller ee39facbf8 net: Revert mlx4 cpumask changes.
This reverts commit 70a640d0da
("net/mlx4_en: Use affinity hint") and commit
c8865b64b0 ("cpumask: Utility function
to set n'th cpu - local cpu first") because these changes break
the build when SMP is disabled amongst other things.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-01 21:58:02 -07:00
Amir Vadai c8865b64b0 cpumask: Utility function to set n'th cpu - local cpu first
This function sets the n'th cpu - local cpu's first.
For example: in a 16 cores server with even cpu's local, will get the
following values:
cpumask_set_cpu_local_first(0, numa, cpumask) => cpu 0 is set
cpumask_set_cpu_local_first(1, numa, cpumask) => cpu 2 is set
...
cpumask_set_cpu_local_first(7, numa, cpumask) => cpu 14 is set
cpumask_set_cpu_local_first(8, numa, cpumask) => cpu 1 is set
cpumask_set_cpu_local_first(9, numa, cpumask) => cpu 3 is set
...
cpumask_set_cpu_local_first(15, numa, cpumask) => cpu 15 is set

Curently this function will be used by multi queue networking devices to
calculate the irq affinity mask, such that as many local cpu's as
possible will be utilized to handle the mq device irq's.

Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-01 19:16:29 -07:00
Brian W Hart cea092c948 cpumask.h: silence warning with -Wsign-compare
Silence the warning when building with -Wsign-compare when cpumask.h
is included:

include/linux/cpumask.h: In function ‘cpumask_parse’:
include/linux/cpumask.h:603:26: warning: signed and unsigned type in conditional expression [-Wsign-compare]
  int len = nl ? nl - buf : strlen(buf);
                          ^

V2: Rusty pointed out that unsigned should be used instead.

Signed-off-by: Brian W Hart <hartb@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-05-14 10:50:06 +09:30
Tejun Heo ba630e4940 cpumask: implement cpumask_parse()
We have cpulist_parse() but not cpumask_parse().  Implement it using
bitmap_parse().

bitmap_parse() is weird in that it takes @len for a string in
kernel-memory which also is inconsistent with bitmap_parselist().
Make cpumask_parse() calculate the length and don't expose the
inconsistency to cpumask users.  Maybe we can fix up bitmap_parse()
later.

This will be used to expose workqueue cpumask knobs to userland via
sysfs.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
2013-03-12 11:30:04 -07:00
Alex Shi 231daf0751 cpumask: cpulist_parse() comments correction
As introduced in Rusty's commit 29c0177e6a, the function has no
parameter @len, so need to remove it from comments to avoid kernel-doc
warning:

alexs@debian:~/linux-next$ scripts/kernel-doc -man
include/linux/cpumask.h | split-man.pl /tmp/man
....
Warning(include/linux/cpumask.h:602): Excess function parameter 'len'
description in 'cpulist_parse'

and correct the function name in comments to cpulist_parse.

Signed-off-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-07-27 09:29:42 +09:30
Alex Shi c777ad6918 cpumask: add a few comments of cpumask functions
Current few cpumask functions' purposes are not quite clear. Stupid
user like myself needs to dig into details for clear function
purpose and return value.
Add few explanation for them is helpful.

Thanks for Srivatsa's comments and correction!

Signed-off-by: Alex Shi <alex.shi@intel.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-07-27 09:29:40 +09:30
Rusty Russell 615399c84d cpumask: remove old cpu_*_map.
These are obsolete: cpu_*_mask provides (const) pointers.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-03-29 15:38:31 +10:30
Srivatsa S. Bhat 38b93780a5 lib/cpumask.c: remove __any_online_cpu()
__any_online_cpu() is not optimal and also unnecessary.  So, replace its
use by faster cpumask_* operations.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-28 17:14:35 -07:00
Paul Gortmaker 187f1882b5 BUG: headers with BUG/BUG_ON etc. need linux/bug.h
If a header file is making use of BUG, BUG_ON, BUILD_BUG_ON, or any
other BUG variant in a static inline (i.e. not in a #define) then
that header really should be including <linux/bug.h> and not just
expecting it to be implicitly present.

We can make this change risk-free, since if the files using these
headers didn't have exposure to linux/bug.h already, they would have
been causing compile failures/warnings.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-03-04 17:54:34 -05:00
KOSAKI Motohiro a64a26e822 cpumask: add cpumask_var_t documentation
cpumask_var_t has one notable difference from cpumask_t.  Add the
explanation.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Thiago Farina <tfransosi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26 16:49:44 -07:00
Mike Travis 4b060420a5 bitmap, irq: add smp_affinity_list interface to /proc/irq
Manually adjusting the smp_affinity for IRQ's becomes unwieldy when the
cpu count is large.

Setting smp affinity to cpus 256 to 263 would be:

	echo 000000ff,00000000,00000000,00000000,00000000,00000000,00000000,00000000 > smp_affinity

instead of:

	echo 256-263 > smp_affinity_list

Think about what it looks like for cpus around say, 4088 to 4095.

We already have many alternate "list" interfaces:

/sys/devices/system/cpu/cpuX/indexY/shared_cpu_list
/sys/devices/system/cpu/cpuX/topology/thread_siblings_list
/sys/devices/system/cpu/cpuX/topology/core_siblings_list
/sys/devices/system/node/nodeX/cpulist
/sys/devices/pci***/***/local_cpulist

Add a companion interface, smp_affinity_list to use cpu lists instead of
cpu maps.  This conforms to other companion interfaces where both a map
and a list interface exists.

This required adding a bitmap_parselist_user() function in a manner
similar to the bitmap_parse_user() function.

[akpm@linux-foundation.org: make __bitmap_parselist() static]
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:45 -07:00
Heiko Carstens 221e3ebf6d cpumask: let num_*_cpus() function always return unsigned values
Dependent on CONFIG_SMP the num_*_cpus() functions return unsigned or
signed values.  Let them always return unsigned values to avoid strange
casts.

Fixes at least one warning:

 kernel/kprobes.c: In function 'register_kretprobe':
 kernel/kprobes.c:1038: warning: comparison of distinct pointer types lacks a cast

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 11:26:29 -08:00
Paul E. McKenney 8bd93a2c5d rcu: Accelerate grace period if last non-dynticked CPU
Currently, rcu_needs_cpu() simply checks whether the current CPU
has an outstanding RCU callback, which means that the last CPU
to go into dyntick-idle mode might wait a few ticks for the
relevant grace periods to complete.  However, if all the other
CPUs are in dyntick-idle mode, and if this CPU is in a quiescent
state (which it is for RCU-bh and RCU-sched any time that we are
considering going into dyntick-idle mode), then the grace period
is instantly complete.

This patch therefore repeatedly invokes the RCU grace-period
machinery in order to force any needed grace periods to complete
quickly.  It does so a limited number of times in order to
prevent starvation by an RCU callback function that might pass
itself to call_rcu().

However, if any CPU other than the current one is not in
dyntick-idle mode, fall back to simply checking (with fix to bug
noted by Lai Jiangshan).  Also, take advantage of last
grace-period forcing, the opportunity to do so noted by Steve
Rostedt.  And apply simplified #ifdef condition suggested by
Frederic Weisbecker.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-15-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 10:34:55 +01:00
Peter Zijlstra 6ad4c18884 sched: Fix balance vs hotplug race
Since (e761b77: cpu hotplug, sched: Introduce cpu_active_map and redo
sched domain managment) we have cpu_active_mask which is suppose to rule
scheduler migration and load-balancing, except it never (fully) did.

The particular problem being solved here is a crash in try_to_wake_up()
where select_task_rq() ends up selecting an offline cpu because
select_task_rq_fair() trusts the sched_domain tree to reflect the
current state of affairs, similarly select_task_rq_rt() trusts the
root_domain.

However, the sched_domains are updated from CPU_DEAD, which is after the
cpu is taken offline and after stop_machine is done. Therefore it can
race perfectly well with code assuming the domains are right.

Cure this by building the domains from cpu_active_mask on
CPU_DOWN_PREPARE.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-06 21:10:56 +01:00
Rusty Russell 6ba2ef7baa cpumask: Move deprecated functions to end of header.
The new ones have pretty kerneldoc.  Move the old ones to the end to
avoid confusing people.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: benh@kernel.crashing.org
2009-09-24 09:34:53 +09:30
Rusty Russell 4b805b1738 cpumask: remove unused deprecated functions, avoid accusations of insanity
We're not forcing removal of the old cpu_ functions, but we might as
well delete the now-unused ones.

Especially CPUMASK_ALLOC and friends.  I actually got a phone call (!)
from a hacker who thought I had introduced them as the new cpumask
API.  He seemed bewildered that I had lost all taste.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: benh@kernel.crashing.org
2009-09-24 09:34:53 +09:30