linux-toradex.git/include/linux/spinlock_api_smp.h, branch v4.14-rc5

locking/spinlocks: Remove the unused spin_lock_bh_nested() API

2017-01-12T08:33:39+00:00

The spin_lock_bh_nested() API is defined but is not used anywhere
in the kernel. So all spin_lock_bh_nested() and related APIs are
now removed.

Signed-off-by: Waiman Long 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1483975612-16447-1-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar

spinlock: Add spin_lock_bh_nested()

2015-01-03T19:32:57+00:00

Signed-off-by: Thomas Graf 
Signed-off-by: David S. Miller

locking: Optimize lock_bh functions

2014-01-13T12:47:36+00:00

Currently all _bh_ lock functions do two preempt_count operations:

  local_bh_disable();
  preempt_disable();

and for the unlock:

  preempt_enable_no_resched();
  local_bh_enable();

Since its a waste of perfectly good cycles to modify the same variable
twice when you can do it in one go; use the new
__local_bh_{dis,en}able_ip() functions that allow us to provide a
preempt_count value to add/sub.

So define SOFTIRQ_LOCK_OFFSET as the offset a _bh_ lock needs to
add/sub to be done in one go.

As a bonus it gets rid of the preempt_enable_no_resched() usage.

This reduces a 1000 loops of:

  spin_lock_bh(&bh_lock);
  spin_unlock_bh(&bh_lock);

from 53596 cycles to 51995 cycles. I didn't do enough measurements to
say for absolute sure that the result is significant but the the few
runs I did for each suggest it is so.

Reviewed-by: Thomas Gleixner 
Signed-off-by: Peter Zijlstra 
Cc: jacob.jun.pan@linux.intel.com
Cc: Mike Galbraith 
Cc: hpa@zytor.com
Cc: Arjan van de Ven 
Cc: lenb@kernel.org
Cc: rjw@rjwysocki.net
Cc: rui.zhang@intel.com
Cc: Linus Torvalds 
Cc: Andrew Morton 
Link: http://lkml.kernel.org/r/20131119151338.GF3694@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar

spinlock_api_smp.h: fix preprocessor comments

2013-06-19T21:34:50+00:00

Correct the related comments for '#ifdef ... #endif'.

Signed-off-by: Chen Gang 
Signed-off-by: Jiri Kosina

locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage

2012-03-23T12:18:57+00:00

Get rid of INLINE_SPIN_UNLOCK entirely replacing it with
UNINLINE_SPIN_UNLOCK instead of the reverse meaning.

Whoever wants to change the default spinlock inlining
behavior and uninline the spinlocks for some weird reason,
such as spinlock debugging, paravirt etc. can now all just
select UNINLINE_SPIN_UNLOCK

Original discussion at: https://lkml.org/lkml/2012/3/21/357

Suggested-by: Linus Torvalds 
Signed-off-by: Raghavendra K T 
Cc: Linus Torvalds 
Cc: Ralf Baechle 
Cc: Chris Metcalf 
Cc: Chris Zankel 
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/20120322095502.30866.75756.sendpatchset@codeblue
[ tidied up the changelog a bit ]
Signed-off-by: Ingo Molnar

locking: Cleanup the name space completely

2009-12-14T22:55:33+00:00

Make the name space hierarchy of locking functions consistent:
     raw_spin* -> _raw_spin* -> __raw_spin*

No functional change.

Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra 
Acked-by: Ingo Molnar

locking: Further name space cleanups

2009-12-14T22:55:33+00:00

The name space hierarchy for the internal lock functions is now a bit
backwards. raw_spin* functions map to _spin* which use __spin*, while
we would like to have _raw_spin* and __raw_spin*.

_raw_spin* is already used by lock debugging, so rename those funtions
to do_raw_spin* to free up the _raw_spin* name space.

No functional change.

Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra 
Acked-by: Ingo Molnar

locking: Implement new raw_spinlock

2009-12-14T22:55:32+00:00

Now that the raw_spin name space is freed up, we can implement
raw_spinlock and the related functions which are used to annotate the
locks which are not converted to sleeping spinlocks in preempt-rt.

A side effect is that only such locks can be used with the low level
lock fsunctions which circumvent lockdep.

For !rt spin_* functions are mapped to the raw_spin* implementations.

Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra 
Acked-by: Ingo Molnar

locking: Separate rwlock api from spinlock api

2009-12-14T22:55:32+00:00

Move the rwlock smp api defines and functions into a separate header
file. Makes the -rt selection simpler and less intrusive.

No functional change.

Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra 
Acked-by: Ingo Molnar

locking: Make inlining decision Kconfig based

2009-11-13T19:53:28+00:00

commit 892a7c67 (locking: Allow arch-inlined spinlocks) implements the
selection of which lock functions are inlined based on defines in
arch/.../spinlock.h: #define __always_inline__LOCK_FUNCTION

Despite of the name __always_inline__* the lock functions can be built
out of line depending on config options. Also if the arch does not set
some inline defines the generic code might set them; again depending on
config options.

This makes it unnecessary hard to figure out when and which lock
functions are inlined. Aside of that it makes it way harder and
messier for -rt to manipulate the lock functions.

Convert the inlining decision to CONFIG switches. Each lock function
is inlined depending on CONFIG_INLINE_*. The configs implement the
existing dependencies. The architecture code can select ARCH_INLINE_*
to signal that it wants the corresponding lock function inlined.
ARCH_INLINE_* is necessary as Kconfig ignores "depends on"
restrictions when a config element is selected.

No functional change.

Signed-off-by: Thomas Gleixner 
LKML-Reference: <20091109151428.504477141@linutronix.de>
Acked-by: Heiko Carstens 
Reviewed-by: Ingo Molnar 
Acked-by: Peter Zijlstra