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  1. 16 2月, 2018 1 次提交
  3. 28 11月, 2017 1 次提交
  5. 02 11月, 2017 1 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      由 Greg Kroah-Hartman 提交于 
      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: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  7. 15 9月, 2017 2 次提交
    • T
      sched/wait: Introduce wakeup boomark in wake_up_page_bit · 11a19c7b
      由 Tim Chen 提交于 
      Now that we have added breaks in the wait queue scan and allow bookmark
on scan position, we put this logic in the wake_up_page_bit function.

We can have very long page wait list in large system where multiple
pages share the same wait list. We break the wake up walk here to allow
other cpus a chance to access the list, and not to disable the interrupts
when traversing the list for too long.  This reduces the interrupt and
rescheduling latency, and excessive page wait queue lock hold time.

[ v2: Remove bookmark_wake_function ]
Signed-off-by: NTim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      11a19c7b
    • T
      sched/wait: Break up long wake list walk · 2554db91
      由 Tim Chen 提交于 
      We encountered workloads that have very long wake up list on large
systems. A waker takes a long time to traverse the entire wake list and
execute all the wake functions.

We saw page wait list that are up to 3700+ entries long in tests of
large 4 and 8 socket systems. It took 0.8 sec to traverse such list
during wake up. Any other CPU that contends for the list spin lock will
spin for a long time. It is a result of the numa balancing migration of
hot pages that are shared by many threads.

Multiple CPUs waking are queued up behind the lock, and the last one
queued has to wait until all CPUs did all the wakeups.

The page wait list is traversed with interrupt disabled, which caused
various problems. This was the original cause that triggered the NMI
watch dog timer in: https://patchwork.kernel.org/patch/9800303/ . Only
extending the NMI watch dog timer there helped.

This patch bookmarks the waker's scan position in wake list and break
the wake up walk, to allow access to the list before the waker resume
its walk down the rest of the wait list. It lowers the interrupt and
rescheduling latency.

This patch also provides a performance boost when combined with the next
patch to break up page wakeup list walk. We saw 22% improvement in the
will-it-scale file pread2 test on a Xeon Phi system running 256 threads.

[ v2: Merged in Linus' changes to remove the bookmark_wake_function, and
  simply access to flags. ]
Reported-by: NKan Liang <kan.liang@intel.com>
Tested-by: NKan Liang <kan.liang@intel.com>
Signed-off-by: NTim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2554db91
  9. 19 8月, 2017 1 次提交
    • L
      wait: add wait_event_killable_timeout() · 8ada9279
      由 Luis R. Rodriguez 提交于 
      These are the few pending fixes I have queued up for v4.13-final.  One
is a a generic regression fix for recursive loops on kmod and the other
one is a trivial print out correction.

During the v4.13 development we assumed that recursive kmod loops were
no longer possible.  Clearly that is not true.  The regression fix makes
use of a new killable wait.  We use a killable wait to be paranoid in
how signals might be sent to modprobe and only accept a proper SIGKILL.
The signal will only be available to userspace to issue *iff* a thread
has already entered a wait state, and that happens only if we've already
throttled after 50 kmod threads have been hit.

Note that although it may seem excessive to trigger a failure afer 5
seconds if all kmod thread remain busy, prior to the series of changes
that went into v4.13 we would actually *always* fatally fail any request
which came in if the limit was already reached.  The new waiting
implemented in v4.13 actually gives us *more* breathing room -- the wait
for 5 seconds is a wait for *any* kmod thread to finish.  We give up and
fail *iff* no kmod thread has finished and they're *all* running
straight for 5 consecutive seconds.  If 50 kmod threads are running
consecutively for 5 seconds something else must be really bad.

Recursive loops with kmod are bad but they're also hard to implement
properly as a selftest without currently fooling current userspace tools
like kmod [1].  For instance kmod will complain when you run depmod if
it finds a recursive loop with symbol dependency between modules as such
this type of recursive loop cannot go upstream as the modules_install
target will fail after running depmod.

These tests already exist on userspace kmod upstream though (refer to
the testsuite/module-playground/mod-loop-*.c files).  The same is not
true if request_module() is used though, or worst if aliases are used.

Likewise the issue with 64-bit kernels booting 32-bit userspace without
a binfmt handler built-in is also currently not detected and proactively
avoided by userspace kmod tools, or kconfig for all architectures.
Although we could complain in the kernel when some of these individual
recursive issues creep up, proactively avoiding these situations in
userspace at build time is what we should keep striving for.

Lastly, since recursive loops could happen with kmod it may mean
recursive loops may also be possible with other kernel usermode helpers,
this should be investigated and long term if we can come up with a more
sensible generic solution even better!

[0] https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git/log/?h=20170809-kmod-for-v4.13-final
[1] https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git

This patch (of 3):

This wait is similar to wait_event_interruptible_timeout() but only
accepts SIGKILL interrupt signal.  Other signals are ignored.

Link: http://lkml.kernel.org/r/20170809234635.13443-2-mcgrof@kernel.orgSigned-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Daniel Mentz <danielmentz@google.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Matt Redfearn <matt.redfearn@imgetc.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8ada9279
  11. 25 7月, 2017 1 次提交
    • J
      sched/wait: Clean up some documentation warnings · 6c423f57
      由 Jonathan Corbet 提交于 
      A couple of kerneldoc comments in <linux/wait.h> had incorrect names for
macro parameters, with this unsightly result:

  ./include/linux/wait.h:555: warning: No description found for parameter 'wq'
  ./include/linux/wait.h:555: warning: Excess function parameter 'wq_head' description in 'wait_event_interruptible_hrtimeout'
  ./include/linux/wait.h:759: warning: No description found for parameter 'wq_head'
  ./include/linux/wait.h:759: warning: Excess function parameter 'wq' description in 'wait_event_killable'

Correct the comments and kill the warnings.
Signed-off-by: NJonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-doc@vger.kernel.org
Link: http://lkml.kernel.org/r/20170724135800.769c4042@lwn.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
      6c423f57
  13. 20 6月, 2017 9 次提交
    • I
      sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming · 2055da97
      由 Ingo Molnar 提交于 
      So I've noticed a number of instances where it was not obvious from the
code whether ->task_list was for a wait-queue head or a wait-queue entry.

Furthermore, there's a number of wait-queue users where the lists are
not for 'tasks' but other entities (poll tables, etc.), in which case
the 'task_list' name is actively confusing.

To clear this all up, name the wait-queue head and entry list structure
fields unambiguously:

	struct wait_queue_head::task_list	=> ::head
	struct wait_queue_entry::task_list	=> ::entry

For example, this code:

	rqw->wait.task_list.next != &wait->task_list

... is was pretty unclear (to me) what it's doing, while now it's written this way:

	rqw->wait.head.next != &wait->entry

... which makes it pretty clear that we are iterating a list until we see the head.

Other examples are:

	list_for_each_entry_safe(pos, next, &x->task_list, task_list) {
	list_for_each_entry(wq, &fence->wait.task_list, task_list) {

... where it's unclear (to me) what we are iterating, and during review it's
hard to tell whether it's trying to walk a wait-queue entry (which would be
a bug), while now it's written as:

	list_for_each_entry_safe(pos, next, &x->head, entry) {
	list_for_each_entry(wq, &fence->wait.head, entry) {

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: NIngo Molnar <mingo@kernel.org>
      2055da97
    • I
      sched/wait: Split out the wait_bit*() APIs from <linux/wait.h> into <linux/wait_bit.h> · 5dd43ce2
      由 Ingo Molnar 提交于 
      The wait_bit*() types and APIs are mixed into wait.h, but they
are a pretty orthogonal extension of wait-queues.

Furthermore, only about 50 kernel files use these APIs, while
over 1000 use the regular wait-queue functionality.

So clean up the main wait.h by moving the wait-bit functionality
out of it, into a separate .h and .c file:

  include/linux/wait_bit.h  for types and APIs
  kernel/sched/wait_bit.c   for the implementation

Update all header dependencies.

This reduces the size of wait.h rather significantly, by about 30%.

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: NIngo Molnar <mingo@kernel.org>
      5dd43ce2
    • I
      sched/wait: Re-adjust macro line continuation backslashes in <linux/wait.h> · 4b1c480b
      由 Ingo Molnar 提交于 
      So there's over 300 CPP macro line-continuation backslashes in
include/linux/wait.h (!!), which are aligned vertically to make
the macro maze a bit more navigable.

The recent renames and reorganization broke some of them, and
instead of re-aligning them in every patch (which would add
a lot of stylistic noise to the patches and make them less
readable), I just ignored them - and fixed them up in a single
go in this patch.

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: NIngo Molnar <mingo@kernel.org>
      4b1c480b
    • I
      sched/wait: Improve the bit-wait API parameter names in the API function prototypes · 939798a0
      由 Ingo Molnar 提交于 
      Contrary to kernel tradition, most of the bit-wait function prototypes
in <linux/wait.h> don't fully define the parameter names, they only
list the types:

	int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);

... which is pretty passive-aggressive in terms of informing the reader
about what these functions are doing.

Fill in the parameter names, such as:

	int out_of_line_wait_on_bit_timeout(void *word, int, wait_bit_action_f *action, unsigned int mode, unsigned long timeout);

Also turn spurious (and inconsistently utilized) cases of 'unsigned' into 'unsigned int'.

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: NIngo Molnar <mingo@kernel.org>
      939798a0
    • I
      sched/wait: Standardize wait_bit_queue naming · 76c85ddc
      由 Ingo Molnar 提交于 
      So wait-bit-queue head variables are often named:

	struct wait_bit_queue *q

... which is a bit ambiguous and super confusing, because
they clearly suggest wait-queue head semantics and behavior
(they rhyme with the old wait_queue_t *q naming), while they
are extended wait-queue _entries_, not heads!

They are misnomers in two ways:

 - the 'wait_bit_queue' leaves open the question of whether
   it's an entry or a head

 - the 'q' parameter and local variable naming falsely implies
   that it's a 'queue' - while it's an entry.

This resulted in sometimes confusing cases such as:

	finish_wait(wq, &q->wait);

where the 'q' is not a wait-queue head, but a wait-bit-queue entry.

So improve this all by standardizing wait-bit-queue nomenclature
similar to wait-queue head naming:

	struct wait_bit_queue   => struct wait_bit_queue_entry
	q			=> wbq_entry

Which makes it all a much clearer:

	struct wait_bit_queue_entry *wbq_entry

... and turns the former confusing piece of code into:

	finish_wait(wq_head, &wbq_entry->wq_entry;

which IMHO makes it apparently clear what we are doing,
without having to analyze the context of the code: we are
adding a wait-queue entry to a regular wait-queue head,
which entry is embedded in a wait-bit-queue entry.

I'm not a big fan of acronyms, but repeating wait_bit_queue_entry
in field and local variable names is too long, so Hopefully it's
clear enough that 'wq_' prefixes stand for wait-queues, while
'wbq_' prefixes stand for wait-bit-queues.

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: NIngo Molnar <mingo@kernel.org>
      76c85ddc
    • I
      sched/wait: Standardize 'struct wait_bit_queue' wait-queue entry field name · 21417136
      由 Ingo Molnar 提交于 
      Rename 'struct wait_bit_queue::wait' to ::wq_entry, to more clearly
name it as a wait-queue entry.

Propagate it to a couple of usage sites where the wait-bit-queue internals
are exposed.

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: NIngo Molnar <mingo@kernel.org>
      21417136
    • I
      sched/wait: Standardize internal naming of wait-queue heads · 9d9d676f
      由 Ingo Molnar 提交于 
      The wait-queue head parameters and variables are named in a
couple of ways, we have the following variants currently:

	wait_queue_head_t *q
	wait_queue_head_t *wq
	wait_queue_head_t *head

In particular the 'wq' naming is ambiguous in the sense whether it's
a wait-queue head or entry name - as entries were often named 'wait'.

( Not to mention the confusion of any readers coming over from
  workqueue-land. )

Standardize all this around a single, unambiguous parameter and
variable name:

	struct wait_queue_head *wq_head

which is easy to grep for and also rhymes nicely with the wait-queue
entry naming:

	struct wait_queue_entry *wq_entry

Also rename:

	struct __wait_queue_head => struct wait_queue_head

... and use this struct type to migrate from typedefs usage to 'struct'
usage, which is more in line with existing kernel practices.

Don't touch any external users and preserve the main wait_queue_head_t
typedef.

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: NIngo Molnar <mingo@kernel.org>
      9d9d676f
    • I
      sched/wait: Standardize internal naming of wait-queue entries · 50816c48
      由 Ingo Molnar 提交于 
      So the various wait-queue entry variables in include/linux/wait.h
and kernel/sched/wait.c are named in a colorfully inconsistent
way:

	wait_queue_entry_t *wait
	wait_queue_entry_t *__wait	(even in plain C code!)
	wait_queue_entry_t *q		(!)
	wait_queue_entry_t *new		(making anyone who knows C++ cringe)
	wait_queue_entry_t *old

I think part of the reason for the inconsistency is the constant
apparent confusion about what a wait queue 'head' versus 'entry' is.

( Some of the documentation talks about a 'wait descriptor', which is
  the wait-queue entry itself - further adding to the confusion. )

The most common name is 'wait', but that in itself is somewhat
ambiguous as well, as it does not really make it clear whether
it's a wait-queue entry or head.

To improve all this name the wait-queue entry structure parameters
and variables consistently and push through this naming into all
the wait.h and wait.c code:

	struct wait_queue_entry *wq_entry

The 'wq_' prefix makes it easy to grep for, and we also use the
opportunity to move away from the typedef to a plain 'struct' naming:
in the kernel we typically reserve typedefs for cases where a
C structure is really small and somewhat opaque - such as pte_t.

wait-queue entries are neither small nor opaque, so use the more
standard 'struct xxx_entry' list management code nomenclature instead.

( We don't touch external users, and we preserve the typedef as well
  for actual wait-queue users, to reduce unnecessary churn. )

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: NIngo Molnar <mingo@kernel.org>
      50816c48
    • I
      sched/wait: Rename wait_queue_t => wait_queue_entry_t · ac6424b9
      由 Ingo Molnar 提交于 
      Rename:

	wait_queue_t		=>	wait_queue_entry_t

'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue",
but in reality it's a queue *entry*. The 'real' queue is the wait queue head,
which had to carry the name.

Start sorting this out by renaming it to 'wait_queue_entry_t'.

This also allows the real structure name 'struct __wait_queue' to
lose its double underscore and become 'struct wait_queue_entry',
which is the more canonical nomenclature for such data types.

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: NIngo Molnar <mingo@kernel.org>
      ac6424b9
  15. 09 3月, 2017 1 次提交
    • L
      sched/headers: fix up header file dependency on <linux/sched/signal.h> · bd0f9b35
      由 Linus Torvalds 提交于 
      The scheduler header file split and cleanups ended up exposing a few
nasty header file dependencies, and in particular it showed how we in
<linux/wait.h> ended up depending on "signal_pending()", which now comes
from <linux/sched/signal.h>.

That's a very subtle and annoying dependency, which already caused a
semantic merge conflict (see commit e58bc927 "Pull overlayfs updates
from Miklos Szeredi", which added that fixup in the merge commit).

It turns out that we can avoid this dependency _and_ improve code
generation by moving the guts of the fairly nasty helper #define
__wait_event_interruptible_locked() to out-of-line code.  The code that
includes the signal_pending() check is all in the slow-path where we
actually go to sleep waiting for the event anyway, so using a helper
function is the right thing to do.

Using a helper function is also what we already did for the non-locked
versions, see the "__wait_event*()" macros and the "prepare_to_wait*()"
set of helper functions.

We might want to try to unify all these macro games, we have a _lot_ of
subtly different wait-event loops.  But this is the minimal patch to fix
the annoying header dependency.
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      bd0f9b35
  17. 02 3月, 2017 1 次提交
  19. 26 12月, 2016 1 次提交
    • T
      ktime: Get rid of the union · 2456e855
      由 Thomas Gleixner 提交于 
      ktime is a union because the initial implementation stored the time in
scalar nanoseconds on 64 bit machine and in a endianess optimized timespec
variant for 32bit machines. The Y2038 cleanup removed the timespec variant
and switched everything to scalar nanoseconds. The union remained, but
become completely pointless.

Get rid of the union and just keep ktime_t as simple typedef of type s64.

The conversion was done with coccinelle and some manual mopping up.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
      2456e855
  21. 30 9月, 2016 4 次提交
  23. 19 7月, 2016 1 次提交
  25. 24 2月, 2016 1 次提交
  27. 14 12月, 2015 1 次提交
  29. 01 12月, 2015 1 次提交
  31. 23 11月, 2015 1 次提交
  33. 23 9月, 2015 1 次提交
  35. 05 9月, 2015 1 次提交
  37. 17 6月, 2015 1 次提交
    • Y
      wait: introduce wait_event_exclusive_cmd · 9f3520c3
      由 Yuanhan Liu 提交于 
      It's just a variant of wait_event_cmd(), with exclusive flag being set.

For cases like RAID5, which puts many processes to sleep until 1/4
resources are free, a wake_up wakes up all processes to run, but
there is one process being able to get the resource as it's protected
by a spin lock. That ends up introducing heavy lock contentions, and
hurts performance badly.

Here introduce wait_event_exclusive_cmd to relieve the lock contention
naturally by letting wake_up just wake up one process.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
v2: its assumed that wait*() and __wait*() have the same arguments - peterz
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NYuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: NNeilBrown <neilb@suse.de>
      9f3520c3
  39. 08 5月, 2015 1 次提交
  41. 05 2月, 2015 1 次提交
    • P
      block: Simplify bsg complete all · 2c561246
      由 Peter Zijlstra 提交于 
      It took me a few tries to figure out what this code did; lets rewrite
it into a more regular form.

The thing that makes this one 'special' is the BSG_F_BLOCK flag, if
that is not set we're not supposed/allowed to block and should spin
wait for completion.

The (new) io_wait_event() will never see a false condition in case of
the spinning and we will therefore not block.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NJens Axboe <axboe@fb.com>
      2c561246
  43. 04 2月, 2015 1 次提交
  45. 03 2月, 2015 1 次提交
  47. 04 11月, 2014 1 次提交
  49. 28 10月, 2014 2 次提交
  51. 25 9月, 2014 1 次提交
    • N
      SCHED: add some "wait..on_bit...timeout()" interfaces. · cbbce822
      由 NeilBrown 提交于 
      In commit c1221321
   sched: Allow wait_on_bit_action() functions to support a timeout

I suggested that a "wait_on_bit_timeout()" interface would not meet my
need.  This isn't true - I was just over-engineering.

Including a 'private' field in wait_bit_key instead of a focused
"timeout" field was just premature generalization.  If some other
use is ever found, it can be generalized or added later.

So this patch renames "private" to "timeout" with a meaning "stop
waiting when "jiffies" reaches or passes "timeout",
and adds two of the many possible wait..bit..timeout() interfaces:

wait_on_page_bit_killable_timeout(), which is the one I want to use,
and out_of_line_wait_on_bit_timeout() which is a reasonably general
example.  Others can be added as needed.
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NNeilBrown <neilb@suse.de>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      cbbce822
  53. 05 9月, 2014 1 次提交