Commit 007dc78f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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

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
  ...
parents 2f1835df d671002b

MAINTAINERS

+0 −1
Original line number Diff line number Diff line
@@ -9100,7 +9100,6 @@ F: arch/*/include/asm/spinlock*.h 
F:	include/linux/rwlock*.h

F:	include/linux/mutex*.h

F:	include/linux/rwsem*.h

F:	arch/*/include/asm/rwsem.h

F:	include/linux/seqlock.h

F:	lib/locking*.[ch]

F:	kernel/locking/

arch/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -907,6 +907,15 @@ config HAVE_ARCH_PREL32_RELOCATIONS 
config ARCH_USE_MEMREMAP_PROT

	bool



config LOCK_EVENT_COUNTS

	bool "Locking event counts collection"

	depends on DEBUG_FS

	---help---

	  Enable light-weight counting of various locking related events

	  in the system with minimal performance impact. This reduces

	  the chance of application behavior change because of timing

	  differences. The counts are reported via debugfs.



source "kernel/gcov/Kconfig"



source "scripts/gcc-plugins/Kconfig"

arch/alpha/Kconfig

+0 −7
Original line number Diff line number Diff line
@@ -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

arch/alpha/include/asm/rwsem.h

deleted100644 → 0
+0 −211
Original line number Diff line number Diff line 
/* 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 */

arch/arc/Kconfig

+0 −3
Original line number Diff line number Diff line
@@ -63,9 +63,6 @@ config SCHED_OMIT_FRAME_POINTER 
config GENERIC_CSUM

	def_bool y



config RWSEM_GENERIC_SPINLOCK

	def_bool y



config ARCH_DISCONTIGMEM_ENABLE

	def_bool n

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