Commit c7eba51c 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:

 - improve rwsem scalability

 - add uninitialized rwsem debugging check

 - reduce lockdep's stacktrace memory usage and add diagnostics

 - misc cleanups, code consolidation and constification

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  mutex: Fix up mutex_waiter usage
  locking/mutex: Use mutex flags macro instead of hard code
  locking/mutex: Make __mutex_owner static to mutex.c
  locking/qspinlock,x86: Clarify virt_spin_lock_key
  locking/rwsem: Check for operations on an uninitialized rwsem
  locking/rwsem: Make handoff writer optimistically spin on owner
  locking/lockdep: Report more stack trace statistics
  locking/lockdep: Reduce space occupied by stack traces
  stacktrace: Constify 'entries' arguments
  locking/lockdep: Make it clear that what lock_class::key points at is not modified
parents cc9b499a e57d1430

arch/x86/include/asm/qspinlock.h

+15 −0
Original line number Diff line number Diff line
@@ -63,10 +63,25 @@ static inline bool vcpu_is_preempted(long cpu) 
#endif



#ifdef CONFIG_PARAVIRT

/*

 * virt_spin_lock_key - enables (by default) the virt_spin_lock() hijack.

 *

 * Native (and PV wanting native due to vCPU pinning) should disable this key.

 * It is done in this backwards fashion to only have a single direction change,

 * which removes ordering between native_pv_spin_init() and HV setup.

 */

DECLARE_STATIC_KEY_TRUE(virt_spin_lock_key);



void native_pv_lock_init(void) __init;



/*

 * Shortcut for the queued_spin_lock_slowpath() function that allows

 * virt to hijack it.

 *

 * Returns:

 *   true - lock has been negotiated, all done;

 *   false - queued_spin_lock_slowpath() will do its thing.

 */

#define virt_spin_lock virt_spin_lock

static inline bool virt_spin_lock(struct qspinlock *lock)

{

include/linux/lockdep.h

+4 −7
Original line number Diff line number Diff line
@@ -66,10 +66,7 @@ struct lock_class_key { 


extern struct lock_class_key __lockdep_no_validate__;



struct lock_trace {

	unsigned int		nr_entries;

	unsigned int		offset;

};

struct lock_trace;



#define LOCKSTAT_POINTS		4
@@ -97,7 +94,7 @@ struct lock_class { 
	 */

	struct list_head		locks_after, locks_before;



	struct lockdep_subclass_key	*key;

	const struct lockdep_subclass_key *key;

	unsigned int			subclass;

	unsigned int			dep_gen_id;
@@ -105,7 +102,7 @@ struct lock_class { 
	 * IRQ/softirq usage tracking bits:

	 */

	unsigned long			usage_mask;

	struct lock_trace		usage_traces[XXX_LOCK_USAGE_STATES];

	const struct lock_trace		*usage_traces[XXX_LOCK_USAGE_STATES];



	/*

	 * Generation counter, when doing certain classes of graph walking,
@@ -193,7 +190,7 @@ struct lock_list { 
	struct list_head		entry;

	struct lock_class		*class;

	struct lock_class		*links_to;

	struct lock_trace		trace;

	const struct lock_trace		*trace;

	int				distance;



	/*

include/linux/mutex.h

+3 −22
Original line number Diff line number Diff line
@@ -65,16 +65,6 @@ struct mutex { 
#endif

};



/*

 * Internal helper function; C doesn't allow us to hide it :/

 *

 * DO NOT USE (outside of mutex code).

 */

static inline struct task_struct *__mutex_owner(struct mutex *lock)

{

	return (struct task_struct *)(atomic_long_read(&lock->owner) & ~0x07);

}



/*

 * This is the control structure for tasks blocked on mutex,

 * which resides on the blocked task's kernel stack:
@@ -144,10 +134,7 @@ extern void __mutex_init(struct mutex *lock, const char *name, 
 *

 * Returns true if the mutex is locked, false if unlocked.

 */

static inline bool mutex_is_locked(struct mutex *lock)

{

	return __mutex_owner(lock) != NULL;

}

extern bool mutex_is_locked(struct mutex *lock);



/*

 * See kernel/locking/mutex.c for detailed documentation of these APIs.
@@ -220,13 +207,7 @@ enum mutex_trylock_recursive_enum { 
 *  - MUTEX_TRYLOCK_SUCCESS   - lock acquired,

 *  - MUTEX_TRYLOCK_RECURSIVE - we already owned the lock.

 */

static inline /* __deprecated */ __must_check enum mutex_trylock_recursive_enum

mutex_trylock_recursive(struct mutex *lock)

{

	if (unlikely(__mutex_owner(lock) == current))

		return MUTEX_TRYLOCK_RECURSIVE;



	return mutex_trylock(lock);

}

extern /* __deprecated */ __must_check enum mutex_trylock_recursive_enum

mutex_trylock_recursive(struct mutex *lock);



#endif /* __LINUX_MUTEX_H */

include/linux/rwsem.h

+10 −0
Original line number Diff line number Diff line
@@ -45,6 +45,9 @@ struct rw_semaphore { 
#endif

	raw_spinlock_t wait_lock;

	struct list_head wait_list;

#ifdef CONFIG_DEBUG_RWSEMS

	void *magic;

#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC

	struct lockdep_map	dep_map;

#endif
@@ -73,6 +76,12 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) 
# define __RWSEM_DEP_MAP_INIT(lockname)

#endif



#ifdef CONFIG_DEBUG_RWSEMS

# define __DEBUG_RWSEM_INITIALIZER(lockname) , .magic = &lockname

#else

# define __DEBUG_RWSEM_INITIALIZER(lockname)

#endif



#ifdef CONFIG_RWSEM_SPIN_ON_OWNER

#define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED

#else
@@ -85,6 +94,7 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) 
	  .wait_list = LIST_HEAD_INIT((name).wait_list),	\

	  .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock)	\

	  __RWSEM_OPT_INIT(name)				\

	  __DEBUG_RWSEM_INITIALIZER(name)			\

	  __RWSEM_DEP_MAP_INIT(name) }



#define DECLARE_RWSEM(name) \

include/linux/stacktrace.h

+2 −2
Original line number Diff line number Diff line
@@ -9,9 +9,9 @@ struct task_struct; 
struct pt_regs;



#ifdef CONFIG_STACKTRACE

void stack_trace_print(unsigned long *trace, unsigned int nr_entries,

void stack_trace_print(const unsigned long *trace, unsigned int nr_entries,

		       int spaces);

int stack_trace_snprint(char *buf, size_t size, unsigned long *entries,

int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,

			unsigned int nr_entries, int spaces);

unsigned int stack_trace_save(unsigned long *store, unsigned int size,

			      unsigned int skipnr);

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