| From | Waiman Long <> | Subject | Re: [patch 30/63] locking/spinlock: Provide RT variant | Date | Wed, 4 Aug 2021 19:34:42 -0400 |
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On 7/30/21 9:50 AM, Thomas Gleixner wrote: > From: Thomas Gleixner <tglx@linutronix.de> > > Provide the actual locking functions which make use of the general and > spinlock specific rtmutex code. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > kernel/locking/Makefile | 1 > kernel/locking/spinlock_rt.c | 128 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 129 insertions(+) > create mode 100644 kernel/locking/spinlock_rt.c > --- > --- a/kernel/locking/Makefile > +++ b/kernel/locking/Makefile > @@ -25,6 +25,7 @@ obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_ > obj-$(CONFIG_PROVE_LOCKING) += spinlock.o > obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o > obj-$(CONFIG_RT_MUTEXES) += rtmutex_api.o > +obj-$(CONFIG_PREEMPT_RT) += spinlock_rt.o > obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o > obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o > obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o > --- /dev/null > +++ b/kernel/locking/spinlock_rt.c > @@ -0,0 +1,128 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * PREEMPT_RT substitution for spin/rw_locks > + * > + * spin_lock and rw_lock on RT are based on rtmutex with a few twists to > + * resemble the non RT semantics > + * > + * - Contrary to a plain rtmutex, spin_lock and rw_lock are state > + * preserving. The task state is saved before blocking on the underlying > + * rtmutex and restored when the lock has been acquired. Regular wakeups > + * during that time are redirected to the saved state so no wake up is > + * missed. > + * > + * - Non RT spin/rw_locks disable preemption and evtl. interrupts.
"evtl."?
Cheers, Longman
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