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Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse Source 
Pull locking updates from Ingo Molnar:
 "Here are the locking changes in this cycle:

   - rwsem unification and simpler micro-optimizations to prepare for
     more intrusive (and more lucrative) scalability improvements in
     v5.3 (Waiman Long)

   - Lockdep irq state tracking flag usage cleanups (Frederic
     Weisbecker)

   - static key improvements (Jakub Kicinski, Peter Zijlstra)

   - misc updates, cleanups and smaller fixes"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
  locking/lockdep: Remove unnecessary unlikely()
  locking/static_key: Don't take sleeping locks in __static_key_slow_dec_deferred()
  locking/static_key: Factor out the fast path of static_key_slow_dec()
  locking/static_key: Add support for deferred static branches
  locking/lockdep: Test all incompatible scenarios at once in check_irq_usage()
  locking/lockdep: Avoid bogus Clang warning
  locking/lockdep: Generate LOCKF_ bit composites
  locking/lockdep: Use expanded masks on find_usage_*() functions
  locking/lockdep: Map remaining magic numbers to lock usage mask names
  locking/lockdep: Move valid_state() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING
  locking/rwsem: Prevent unneeded warning during locking selftest
  locking/rwsem: Optimize rwsem structure for uncontended lock acquisition
  locking/rwsem: Enable lock event counting
  locking/lock_events: Don't show pvqspinlock events on bare metal
  locking/lock_events: Make lock_events available for all archs & other locks
  locking/qspinlock_stat: Introduce generic lockevent_*() counting APIs
  locking/rwsem: Enhance DEBUG_RWSEMS_WARN_ON() macro
  locking/rwsem: Add debug check for __down_read*()
  locking/rwsem: Micro-optimize rwsem_try_read_lock_unqueued()
  locking/rwsem: Move rwsem internal function declarations to rwsem-xadd.h
  ...
This commit is contained in:
Linus Torvalds
2019-05-06 13:50:15 -07:00
parent 2f1835dffa d671002be6
commit 007dc78fea
62 changed files with 989 additions and 1931 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
arch/alpha/Kconfig
View File

@@ -50,13 +50,6 @@ config MMU
bool
default y
config RWSEM_GENERIC_SPINLOCK
bool
config RWSEM_XCHGADD_ALGORITHM
bool
default y
config ARCH_HAS_ILOG2_U32
bool
default n

211
arch/alpha/include/asm/rwsem.h
View File

@@ -1,211 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ALPHA_RWSEM_H
#define _ALPHA_RWSEM_H
/*
* Written by Ivan Kokshaysky <ink@jurassic.park.msu.ru>, 2001.
* Based on asm-alpha/semaphore.h and asm-i386/rwsem.h
*/
#ifndef _LINUX_RWSEM_H
#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
#endif
#ifdef __KERNEL__
#include <linux/compiler.h>
#define RWSEM_UNLOCKED_VALUE 0x0000000000000000L
#define RWSEM_ACTIVE_BIAS 0x0000000000000001L
#define RWSEM_ACTIVE_MASK 0x00000000ffffffffL
#define RWSEM_WAITING_BIAS (-0x0000000100000000L)
#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
static inline int ___down_read(struct rw_semaphore *sem)
{
long oldcount;
#ifndef CONFIG_SMP
oldcount = sem->count.counter;
sem->count.counter += RWSEM_ACTIVE_READ_BIAS;
#else
long temp;
__asm__ __volatile__(
"1: ldq_l %0,%1\n"
" addq %0,%3,%2\n"
" stq_c %2,%1\n"
" beq %2,2f\n"
" mb\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
:"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory");
#endif
return (oldcount < 0);
}
static inline void __down_read(struct rw_semaphore *sem)
{
if (unlikely(___down_read(sem)))
rwsem_down_read_failed(sem);
}
static inline int __down_read_killable(struct rw_semaphore *sem)
{
if (unlikely(___down_read(sem)))
if (IS_ERR(rwsem_down_read_failed_killable(sem)))
return -EINTR;
return 0;
}
/*
* trylock for reading -- returns 1 if successful, 0 if contention
*/
static inline int __down_read_trylock(struct rw_semaphore *sem)
{
long old, new, res;
res = atomic_long_read(&sem->count);
do {
new = res + RWSEM_ACTIVE_READ_BIAS;
if (new <= 0)
break;
old = res;
res = atomic_long_cmpxchg(&sem->count, old, new);
} while (res != old);
return res >= 0 ? 1 : 0;
}
static inline long ___down_write(struct rw_semaphore *sem)
{
long oldcount;
#ifndef CONFIG_SMP
oldcount = sem->count.counter;
sem->count.counter += RWSEM_ACTIVE_WRITE_BIAS;
#else
long temp;
__asm__ __volatile__(
"1: ldq_l %0,%1\n"
" addq %0,%3,%2\n"
" stq_c %2,%1\n"
" beq %2,2f\n"
" mb\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
:"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory");
#endif
return oldcount;
}
static inline void __down_write(struct rw_semaphore *sem)
{
if (unlikely(___down_write(sem)))
rwsem_down_write_failed(sem);
}
static inline int __down_write_killable(struct rw_semaphore *sem)
{
if (unlikely(___down_write(sem))) {
if (IS_ERR(rwsem_down_write_failed_killable(sem)))
return -EINTR;
}
return 0;
}
/*
* trylock for writing -- returns 1 if successful, 0 if contention
*/
static inline int __down_write_trylock(struct rw_semaphore *sem)
{
long ret = atomic_long_cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
RWSEM_ACTIVE_WRITE_BIAS);
if (ret == RWSEM_UNLOCKED_VALUE)
return 1;
return 0;
}
static inline void __up_read(struct rw_semaphore *sem)
{
long oldcount;
#ifndef CONFIG_SMP
oldcount = sem->count.counter;
sem->count.counter -= RWSEM_ACTIVE_READ_BIAS;
#else
long temp;
__asm__ __volatile__(
" mb\n"
"1: ldq_l %0,%1\n"
" subq %0,%3,%2\n"
" stq_c %2,%1\n"
" beq %2,2f\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
:"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory");
#endif
if (unlikely(oldcount < 0))
if ((int)oldcount - RWSEM_ACTIVE_READ_BIAS == 0)
rwsem_wake(sem);
}
static inline void __up_write(struct rw_semaphore *sem)
{
long count;
#ifndef CONFIG_SMP
sem->count.counter -= RWSEM_ACTIVE_WRITE_BIAS;
count = sem->count.counter;
#else
long temp;
__asm__ __volatile__(
" mb\n"
"1: ldq_l %0,%1\n"
" subq %0,%3,%2\n"
" stq_c %2,%1\n"
" beq %2,2f\n"
" subq %0,%3,%0\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (count), "=m" (sem->count), "=&r" (temp)
:"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory");
#endif
if (unlikely(count))
if ((int)count == 0)
rwsem_wake(sem);
}
/*
* downgrade write lock to read lock
*/
static inline void __downgrade_write(struct rw_semaphore *sem)
{
long oldcount;
#ifndef CONFIG_SMP
oldcount = sem->count.counter;
sem->count.counter -= RWSEM_WAITING_BIAS;
#else
long temp;
__asm__ __volatile__(
"1: ldq_l %0,%1\n"
" addq %0,%3,%2\n"
" stq_c %2,%1\n"
" beq %2,2f\n"
" mb\n"
".subsection 2\n"
"2: br 1b\n"
".previous"
:"=&r" (oldcount), "=m" (sem->count), "=&r" (temp)
:"Ir" (-RWSEM_WAITING_BIAS), "m" (sem->count) : "memory");
#endif
if (unlikely(oldcount < 0))
rwsem_downgrade_wake(sem);
}
#endif /* __KERNEL__ */
#endif /* _ALPHA_RWSEM_H */