Commit graph

3 commits

Author SHA1 Message Date
Randy Dunlap 51e69e6551 Documentation/locking/locktypes: Minor copy editor fixes
Minor editorial fixes:
- remove 'enabled' from PREEMPT_RT enabled kernels for consistency
- add some periods for consistency
- add "'" for possessive CPU's
- spell out interrupts

[ tglx: Picked up Paul's suggestions ]

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/ac615f36-0b44-408d-aeab-d76e4241add4@infradead.org
2020-03-28 12:47:34 +01:00
Thomas Gleixner 7ecc6aa522 Documentation/locking/locktypes: Further clarifications and wordsmithing
The documentation of rw_semaphores is wrong as it claims that the non-owner
reader release is not supported by RT. That's just history biased memory
distortion.

Split the 'Owner semantics' section up and add separate sections for
semaphore and rw_semaphore to reflect reality.

Aside of that the following updates are done:

 - Add pseudo code to document the spinlock state preserving mechanism on
   PREEMPT_RT

 - Wordsmith the bitspinlock and lock nesting sections

Co-developed-by: Paul McKenney <paulmck@kernel.org>
Signed-off-by: Paul McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/87wo78y5yy.fsf@nanos.tec.linutronix.de
2020-03-28 12:47:34 +01:00
Thomas Gleixner 919e9e6395 Documentation: Add lock ordering and nesting documentation
The kernel provides a variety of locking primitives. The nesting of these
lock types and the implications of them on RT enabled kernels is nowhere
documented.

Add initial documentation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200321113242.026561244@linutronix.de
2020-03-21 16:00:23 +01:00