linux-toradex.git/kernel/sched/wait_bit.c, branch v5.16-rc3

sched/wait: fix ___wait_var_event(exclusive)

2019-12-17T12:32:50+00:00

init_wait_var_entry() forgets to initialize wq_entry->flags.

Currently not a problem, we don't have wait_var_event_exclusive().

Signed-off-by: Oleg Nesterov 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Vincent Guittot 
Cc: Ingo Molnar 
Cc: Felipe Balbi 
Cc: Linus Torvalds 
Cc: Miklos Szeredi 
Cc: Juri Lelli 
Link: https://lkml.kernel.org/r/20191210191902.GB14449@redhat.com

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45+00:00

Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

sched/wait: Improve __var_waitqueue() code generation

2018-03-20T07:23:25+00:00

Since we fixed hash_64() to not suck there is no need to play games to
attempt to improve the hash value on 64-bit.

Also, since we don't use the bit value for the variables, use hash_ptr()
directly.

No change in functionality.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: George Spelvin 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/wait: Remove the wait_on_atomic_t() API

2018-03-20T07:23:24+00:00

There are no users left (everyone got converted to wait_var_event()), remove it.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/wait: Introduce wait_var_event()

2018-03-20T07:23:17+00:00

As a replacement for the wait_on_atomic_t() API provide the
wait_var_event() API.

The wait_var_event() API is based on the very same hashed-waitqueue
idea, but doesn't care about the type (atomic_t) or the specific
condition (atomic_read() == 0). IOW. it's much more widely
applicable/flexible.

It shares all the benefits/disadvantages of a hashed-waitqueue
approach with the existing wait_on_atomic_t/wait_on_bit() APIs.

The API is modeled after the existing wait_event() API, but instead of
taking a wait_queue_head, it takes an address. This addresses is
hashed to obtain a wait_queue_head from the bit_wait_table.

Similar to the wait_event() API, it takes a condition expression as
second argument and will wait until this expression becomes true.

The following are (mostly) identical replacements:

	wait_on_atomic_t(&my_atomic, atomic_t_wait, TASK_UNINTERRUPTIBLE);
	wake_up_atomic_t(&my_atomic);

	wait_var_event(&my_atomic, !atomic_read(&my_atomic));
	wake_up_var(&my_atomic);

The only difference is that wake_up_var() is an unconditional wakeup
and doesn't check the previously hard-coded (atomic_read() == 0)
condition here. This is of little concequence, since most callers are
already conditional on atomic_dec_and_test() and the ones that are
not, are trivial to make so.

Tested-by: Dan Williams 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: David Howells 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/headers: Simplify and clean up header usage in the scheduler

2018-03-04T11:39:29+00:00

Do the following cleanups and simplifications:

 - sched/sched.h already includes , so no need to
   include it in sched/core.c again.

 - order the  headers alphabetically

 - add all  headers to kernel/sched/sched.h

 - remove all unnecessary includes from the .c files that
   are already included in kernel/sched/sched.h.

Finally, make all scheduler .c files use a single common header:

  #include "sched.h"

... which now contains a union of the relied upon headers.

This makes the various .c files easier to read and easier to handle.

Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched: Clean up and harmonize the coding style of the scheduler code base

2018-03-03T14:50:21+00:00

A good number of small style inconsistencies have accumulated
in the scheduler core, so do a pass over them to harmonize
all these details:

 - fix speling in comments,

 - use curly braces for multi-line statements,

 - remove unnecessary parentheses from integer literals,

 - capitalize consistently,

 - remove stray newlines,

 - add comments where necessary,

 - remove invalid/unnecessary comments,

 - align structure definitions and other data types vertically,

 - add missing newlines for increased readability,

 - fix vertical tabulation where it's misaligned,

 - harmonize preprocessor conditional block labeling
   and vertical alignment,

 - remove line-breaks where they uglify the code,

 - add newline after local variable definitions,

No change in functionality:

  md5:
     1191fa0a890cfa8132156d2959d7e9e2  built-in.o.before.asm
     1191fa0a890cfa8132156d2959d7e9e2  built-in.o.after.asm

Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

Pass mode to wait_on_atomic_t() action funcs and provide default actions

2017-11-13T15:38:16+00:00

Make wait_on_atomic_t() pass the TASK_* mode onto its action function as an
extra argument and make it 'unsigned int throughout.

Also, consolidate a bunch of identical action functions into a default
function that can do the appropriate thing for the mode.

Also, change the argument name in the bit_wait*() function declarations to
reflect the fact that it's the mode and not the bit number.

[Peter Z gives this a grudging ACK, but thinks that the whole atomic_t wait
should be done differently, though he's not immediately sure as to how]

Signed-off-by: David Howells 
Acked-by: Peter Zijlstra 
cc: Ingo Molnar

sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming

2017-06-20T10:19:14+00:00

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 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/wait: Move bit_wait_table[] and related functionality from sched/core.c to sched/wait_bit.c

2017-06-20T10:19:14+00:00

The key hashed waitqueue data structures and their initialization
was done in the main scheduler file for no good reason, move them
to sched/wait_bit.c instead.

Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar