Commit 8efb90cf authored by Linus Torvalds's avatar Linus Torvalds

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

Pull locking updates from Ingo Molnar:
 "The main changes in this cycle are:

   - big rtmutex and futex cleanup and robustification from Thomas
     Gleixner
   - mutex optimizations and refinements from Jason Low
   - arch_mutex_cpu_relax() removal and related cleanups
   - smaller lockdep tweaks"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  arch, locking: Ciao arch_mutex_cpu_relax()
  locking/lockdep: Only ask for /proc/lock_stat output when available
  locking/mutexes: Optimize mutex trylock slowpath
  locking/mutexes: Try to acquire mutex only if it is unlocked
  locking/mutexes: Delete the MUTEX_SHOW_NO_WAITER macro
  locking/mutexes: Correct documentation on mutex optimistic spinning
  rtmutex: Make the rtmutex tester depend on BROKEN
  futex: Simplify futex_lock_pi_atomic() and make it more robust
  futex: Split out the first waiter attachment from lookup_pi_state()
  futex: Split out the waiter check from lookup_pi_state()
  futex: Use futex_top_waiter() in lookup_pi_state()
  futex: Make unlock_pi more robust
  rtmutex: Avoid pointless requeueing in the deadlock detection chain walk
  rtmutex: Cleanup deadlock detector debug logic
  rtmutex: Confine deadlock logic to futex
  rtmutex: Simplify remove_waiter()
  rtmutex: Document pi chain walk
  rtmutex: Clarify the boost/deboost part
  rtmutex: No need to keep task ref for lock owner check
  rtmutex: Simplify and document try_to_take_rtmutex()
  ...
parents 5bda4f63 3a6bfbc9
......@@ -57,6 +57,7 @@ unsigned long get_wchan(struct task_struct *p);
((tsk) == current ? rdusp() : task_thread_info(tsk)->pcb.usp)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#define ARCH_HAS_PREFETCH
#define ARCH_HAS_PREFETCHW
......
......@@ -62,6 +62,8 @@ unsigned long thread_saved_pc(struct task_struct *t);
#define cpu_relax() do { } while (0)
#endif
#define cpu_relax_lowlatency() cpu_relax()
#define copy_segments(tsk, mm) do { } while (0)
#define release_segments(mm) do { } while (0)
......
......@@ -82,6 +82,8 @@ unsigned long get_wchan(struct task_struct *p);
#define cpu_relax() barrier()
#endif
#define cpu_relax_lowlatency() cpu_relax()
#define task_pt_regs(p) \
((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)
......
......@@ -129,6 +129,7 @@ extern void release_thread(struct task_struct *);
unsigned long get_wchan(struct task_struct *p);
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
/* Thread switching */
extern struct task_struct *cpu_switch_to(struct task_struct *prev,
......
......@@ -92,6 +92,7 @@ extern struct avr32_cpuinfo boot_cpu_data;
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 3))
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#define cpu_sync_pipeline() asm volatile("sub pc, -2" : : : "memory")
struct cpu_context {
......
......@@ -99,7 +99,7 @@ unsigned long get_wchan(struct task_struct *p);
#define KSTK_ESP(tsk) ((tsk) == current ? rdusp() : (tsk)->thread.usp)
#define cpu_relax() smp_mb()
#define cpu_relax_lowlatency() cpu_relax()
/* Get the Silicon Revision of the chip */
static inline uint32_t __pure bfin_revid(void)
......
......@@ -121,6 +121,7 @@ extern unsigned long get_wchan(struct task_struct *p);
#define KSTK_ESP(task) (task_pt_regs(task)->sp)
#define cpu_relax() do { } while (0)
#define cpu_relax_lowlatency() cpu_relax()
extern const struct seq_operations cpuinfo_op;
......
......@@ -63,6 +63,7 @@ static inline void release_thread(struct task_struct *dead_task)
#define init_stack (init_thread_union.stack)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
void default_idle(void);
......
......@@ -56,6 +56,7 @@ struct thread_struct {
}
#define cpu_relax() __vmyield()
#define cpu_relax_lowlatency() cpu_relax()
/*
* Decides where the kernel will search for a free chunk of vm space during
......
......@@ -548,6 +548,7 @@ ia64_eoi (void)
}
#define cpu_relax() ia64_hint(ia64_hint_pause)
#define cpu_relax_lowlatency() cpu_relax()
static inline int
ia64_get_irr(unsigned int vector)
......
......@@ -133,5 +133,6 @@ unsigned long get_wchan(struct task_struct *p);
#define KSTK_ESP(tsk) ((tsk)->thread.sp)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#endif /* _ASM_M32R_PROCESSOR_H */
......@@ -176,5 +176,6 @@ unsigned long get_wchan(struct task_struct *p);
#define task_pt_regs(tsk) ((struct pt_regs *) ((tsk)->thread.esp0))
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#endif
......@@ -155,6 +155,7 @@ unsigned long get_wchan(struct task_struct *p);
#define user_stack_pointer(regs) ((regs)->ctx.AX[0].U0)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
extern void setup_priv(void);
......
......@@ -22,6 +22,7 @@
extern const struct seq_operations cpuinfo_op;
# define cpu_relax() barrier()
# define cpu_relax_lowlatency() cpu_relax()
#define task_pt_regs(tsk) \
(((struct pt_regs *)(THREAD_SIZE + task_stack_page(tsk))) - 1)
......
......@@ -367,6 +367,7 @@ unsigned long get_wchan(struct task_struct *p);
#define KSTK_STATUS(tsk) (task_pt_regs(tsk)->cp0_status)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
/*
* Return_address is a replacement for __builtin_return_address(count)
......
......@@ -68,7 +68,9 @@ extern struct mn10300_cpuinfo cpu_data[];
extern void identify_cpu(struct mn10300_cpuinfo *);
extern void print_cpu_info(struct mn10300_cpuinfo *);
extern void dodgy_tsc(void);
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
/*
* User space process size: 1.75GB (default).
......
......@@ -101,6 +101,7 @@ extern unsigned long thread_saved_pc(struct task_struct *t);
#define init_stack (init_thread_union.stack)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#endif /* __ASSEMBLY__ */
#endif /* __ASM_OPENRISC_PROCESSOR_H */
......@@ -338,6 +338,7 @@ extern unsigned long get_wchan(struct task_struct *p);
#define KSTK_ESP(tsk) ((tsk)->thread.regs.gr[30])
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
/* Used as a macro to identify the combined VIPT/PIPT cached
* CPUs which require a guarantee of coherency (no inequivalent
......
......@@ -400,6 +400,8 @@ static inline unsigned long __pack_fe01(unsigned int fpmode)
#define cpu_relax() barrier()
#endif
#define cpu_relax_lowlatency() cpu_relax()
/* Check that a certain kernel stack pointer is valid in task_struct p */
int validate_sp(unsigned long sp, struct task_struct *p,
unsigned long nbytes);
......
......@@ -217,7 +217,7 @@ static inline void cpu_relax(void)
barrier();
}
#define arch_mutex_cpu_relax() barrier()
#define cpu_relax_lowlatency() barrier()
static inline void psw_set_key(unsigned int key)
{
......
......@@ -24,6 +24,7 @@ extern unsigned long get_wchan(struct task_struct *p);
#define current_text_addr() ({ __label__ _l; _l: &&_l; })
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#define release_thread(thread) do {} while (0)
/*
......
......@@ -97,6 +97,7 @@ extern struct sh_cpuinfo cpu_data[];
#define cpu_sleep() __asm__ __volatile__ ("sleep" : : : "memory")
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
void default_idle(void);
void stop_this_cpu(void *);
......
......@@ -119,6 +119,8 @@ extern struct task_struct *last_task_used_math;
int do_mathemu(struct pt_regs *regs, struct task_struct *fpt);
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
extern void (*sparc_idle)(void);
#endif
......
......@@ -216,6 +216,7 @@ unsigned long get_wchan(struct task_struct *task);
"nop\n\t" \
".previous" \
::: "memory")
#define cpu_relax_lowlatency() cpu_relax()
/* Prefetch support. This is tuned for UltraSPARC-III and later.
* UltraSPARC-I will treat these as nops, and UltraSPARC-II has
......
......@@ -266,6 +266,8 @@ static inline void cpu_relax(void)
barrier();
}
#define cpu_relax_lowlatency() cpu_relax()
/* Info on this processor (see fs/proc/cpuinfo.c) */
struct seq_operations;
extern const struct seq_operations cpuinfo_op;
......
......@@ -71,6 +71,7 @@ extern void release_thread(struct task_struct *);
unsigned long get_wchan(struct task_struct *p);
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#define task_pt_regs(p) \
((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)
......
......@@ -99,7 +99,7 @@
#if defined(CONFIG_X86_PPRO_FENCE)
/*
* For either of these options x86 doesn't have a strong TSO memory
* For this option x86 doesn't have a strong TSO memory
* model and we should fall back to full barriers.
*/
......
......@@ -696,6 +696,8 @@ static inline void cpu_relax(void)
rep_nop();
}
#define cpu_relax_lowlatency() cpu_relax()
/* Stop speculative execution and prefetching of modified code. */
static inline void sync_core(void)
{
......
......@@ -3,7 +3,7 @@
#include <asm-generic/qrwlock_types.h>
#if !defined(CONFIG_X86_OOSTORE) && !defined(CONFIG_X86_PPRO_FENCE)
#ifndef CONFIG_X86_PPRO_FENCE
#define queue_write_unlock queue_write_unlock
static inline void queue_write_unlock(struct qrwlock *lock)
{
......
......@@ -26,6 +26,7 @@ static inline void rep_nop(void)
}
#define cpu_relax() rep_nop()
#define cpu_relax_lowlatency() cpu_relax()
#include <asm/processor-generic.h>
......
......@@ -182,6 +182,7 @@ extern unsigned long get_wchan(struct task_struct *p);
#define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1])
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
/* Special register access. */
......
......@@ -176,8 +176,4 @@ extern void mutex_unlock(struct mutex *lock);
extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
#ifndef arch_mutex_cpu_relax
# define arch_mutex_cpu_relax() cpu_relax()
#endif
#endif /* __LINUX_MUTEX_H */
......@@ -90,11 +90,9 @@ extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
extern void rt_mutex_destroy(struct rt_mutex *lock);
extern void rt_mutex_lock(struct rt_mutex *lock);
extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
int detect_deadlock);
extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
extern int rt_mutex_timed_lock(struct rt_mutex *lock,
struct hrtimer_sleeper *timeout,
int detect_deadlock);
struct hrtimer_sleeper *timeout);
extern int rt_mutex_trylock(struct rt_mutex *lock);
......
......@@ -164,8 +164,6 @@ static inline unsigned read_seqcount_begin(const seqcount_t *s)
static inline unsigned raw_seqcount_begin(const seqcount_t *s)
{
unsigned ret = ACCESS_ONCE(s->sequence);
seqcount_lockdep_reader_access(s);
smp_rmb();
return ret & ~1;
}
......
This diff is collapsed.
......@@ -384,7 +384,9 @@ static void print_lockdep_off(const char *bug_msg)
{
printk(KERN_DEBUG "%s\n", bug_msg);
printk(KERN_DEBUG "turning off the locking correctness validator.\n");
#ifdef CONFIG_LOCK_STAT
printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
#endif
}
static int save_trace(struct stack_trace *trace)
......
#include <linux/percpu.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include "mcs_spinlock.h"
......@@ -79,7 +77,7 @@ osq_wait_next(struct optimistic_spin_queue *lock,
break;
}
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
}
return next;
......@@ -120,7 +118,7 @@ bool osq_lock(struct optimistic_spin_queue *lock)
if (need_resched())
goto unqueue;
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
}
return true;
......@@ -146,7 +144,7 @@ bool osq_lock(struct optimistic_spin_queue *lock)
if (smp_load_acquire(&node->locked))
return true;
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
/*
* Or we race against a concurrent unqueue()'s step-B, in which
......
......@@ -27,7 +27,7 @@ struct mcs_spinlock {
#define arch_mcs_spin_lock_contended(l) \
do { \
while (!(smp_load_acquire(l))) \
arch_mutex_cpu_relax(); \
cpu_relax_lowlatency(); \
} while (0)
#endif
......@@ -104,7 +104,7 @@ void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node)
return;
/* Wait until the next pointer is set */
while (!(next = ACCESS_ONCE(node->next)))
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
}
/* Pass lock to next waiter. */
......
......@@ -46,12 +46,6 @@
# include <asm/mutex.h>
#endif
/*
* A negative mutex count indicates that waiters are sleeping waiting for the
* mutex.
*/
#define MUTEX_SHOW_NO_WAITER(mutex) (atomic_read(&(mutex)->count) >= 0)
void
__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
{
......@@ -152,7 +146,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
if (need_resched())
break;
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
}
rcu_read_unlock();
......@@ -388,12 +382,10 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
/*
* Optimistic spinning.
*
* We try to spin for acquisition when we find that there are no
* pending waiters and the lock owner is currently running on a
* (different) CPU.
*
* The rationale is that if the lock owner is running, it is likely to
* release the lock soon.
* We try to spin for acquisition when we find that the lock owner
* is currently running on a (different) CPU and while we don't
* need to reschedule. The rationale is that if the lock owner is
* running, it is likely to release the lock soon.
*
* Since this needs the lock owner, and this mutex implementation
* doesn't track the owner atomically in the lock field, we need to
......@@ -440,7 +432,8 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
if (owner && !mutex_spin_on_owner(lock, owner))
break;
if ((atomic_read(&lock->count) == 1) &&
/* Try to acquire the mutex if it is unlocked. */
if (!mutex_is_locked(lock) &&
(atomic_cmpxchg(&lock->count, 1, 0) == 1)) {
lock_acquired(&lock->dep_map, ip);
if (use_ww_ctx) {
......@@ -471,7 +464,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* memory barriers as we'll eventually observe the right
* values at the cost of a few extra spins.
*/
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
}
osq_unlock(&lock->osq);
slowpath:
......@@ -485,8 +478,11 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
#endif
spin_lock_mutex(&lock->wait_lock, flags);
/* once more, can we acquire the lock? */
if (MUTEX_SHOW_NO_WAITER(lock) && (atomic_xchg(&lock->count, 0) == 1))
/*
* Once more, try to acquire the lock. Only try-lock the mutex if
* it is unlocked to reduce unnecessary xchg() operations.
*/
if (!mutex_is_locked(lock) && (atomic_xchg(&lock->count, 0) == 1))
goto skip_wait;
debug_mutex_lock_common(lock, &waiter);
......@@ -506,9 +502,10 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* it's unlocked. Later on, if we sleep, this is the
* operation that gives us the lock. We xchg it to -1, so
* that when we release the lock, we properly wake up the
* other waiters:
* other waiters. We only attempt the xchg if the count is
* non-negative in order to avoid unnecessary xchg operations:
*/
if (MUTEX_SHOW_NO_WAITER(lock) &&
if (atomic_read(&lock->count) >= 0 &&
(atomic_xchg(&lock->count, -1) == 1))
break;
......@@ -823,6 +820,10 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
unsigned long flags;
int prev;
/* No need to trylock if the mutex is locked. */
if (mutex_is_locked(lock))
return 0;
spin_lock_mutex(&lock->wait_lock, flags);
prev = atomic_xchg(&lock->count, -1);
......
......@@ -20,7 +20,6 @@
#include <linux/cpumask.h>
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/mutex.h>
#include <asm/qrwlock.h>
/**
......@@ -35,7 +34,7 @@ static __always_inline void
rspin_until_writer_unlock(struct qrwlock *lock, u32 cnts)
{
while ((cnts & _QW_WMASK) == _QW_LOCKED) {
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
cnts = smp_load_acquire((u32 *)&lock->cnts);
}
}
......@@ -75,7 +74,7 @@ void queue_read_lock_slowpath(struct qrwlock *lock)
* to make sure that the write lock isn't taken.
*/
while (atomic_read(&lock->cnts) & _QW_WMASK)
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
cnts = atomic_add_return(_QR_BIAS, &lock->cnts) - _QR_BIAS;
rspin_until_writer_unlock(lock, cnts);
......@@ -114,7 +113,7 @@ void queue_write_lock_slowpath(struct qrwlock *lock)
cnts | _QW_WAITING) == cnts))
break;
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
}
/* When no more readers, set the locked flag */
......@@ -125,7 +124,7 @@ void queue_write_lock_slowpath(struct qrwlock *lock)
_QW_LOCKED) == _QW_WAITING))
break;
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
}
unlock:
arch_spin_unlock(&lock->lock);
......
......@@ -66,12 +66,13 @@ void rt_mutex_debug_task_free(struct task_struct *task)
* the deadlock. We print when we return. act_waiter can be NULL in
* case of a remove waiter operation.
*/
void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter,
void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk,
struct rt_mutex_waiter *act_waiter,
struct rt_mutex *lock)
{
struct task_struct *task;
if (!debug_locks || detect || !act_waiter)
if (!debug_locks || chwalk == RT_MUTEX_FULL_CHAINWALK || !act_waiter)
return;
task = rt_mutex_owner(act_waiter->lock);
......
......@@ -20,14 +20,15 @@ extern void debug_rt_mutex_unlock(struct rt_mutex *lock);
extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
struct task_struct *powner);
extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
extern void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *waiter,
extern void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk,
struct rt_mutex_waiter *waiter,
struct rt_mutex *lock);
extern void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter);
# define debug_rt_mutex_reset_waiter(w) \
do { (w)->deadlock_lock = NULL; } while (0)
static inline int debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
int detect)
static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
enum rtmutex_chainwalk walk)
{
return (waiter != NULL);
}
......
This diff is collapsed.
......@@ -22,10 +22,15 @@
#define debug_rt_mutex_init(m, n) do { } while (0)
#define debug_rt_mutex_deadlock(d, a ,l) do { } while (0)
#define debug_rt_mutex_print_deadlock(w) do { } while (0)
#define debug_rt_mutex_detect_deadlock(w,d) (d)
#define debug_rt_mutex_reset_waiter(w) do { } while (0)
static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
{
WARN(1, "rtmutex deadlock detected\n");
}
static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *w,
enum rtmutex_chainwalk walk)
{
return walk == RT_MUTEX_FULL_CHAINWALK;
}
......@@ -101,6 +101,21 @@ static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
}
/*
* Constants for rt mutex functions which have a selectable deadlock
* detection.
*
* RT_MUTEX_MIN_CHAINWALK: Stops the lock chain walk when there are
* no further PI adjustments to be made.
*
* RT_MUTEX_FULL_CHAINWALK: Invoke deadlock detection with a full
* walk of the lock chain.
*/
enum rtmutex_chainwalk {
RT_MUTEX_MIN_CHAINWALK,
RT_MUTEX_FULL_CHAINWALK,
};
/*
* PI-futex support (proxy locking functions, etc.):
*/
......@@ -111,12 +126,11 @@ extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
struct task_struct *proxy_owner);
extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter,
struct task_struct *task,
int detect_deadlock);
struct task_struct *task);
extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
struct hrtimer_sleeper *to,
struct rt_mutex_waiter *waiter,
int detect_deadlock);
struct rt_mutex_waiter *waiter);
extern int rt_mutex_timed_futex_lock(struct rt_mutex *l, struct hrtimer_sleeper *to);
#ifdef CONFIG_DEBUG_RT_MUTEXES
# include "rtmutex-debug.h"
......
......@@ -329,7 +329,7 @@ bool rwsem_spin_on_owner(struct rw_semaphore *sem, struct task_struct *owner)
if (need_resched())
break;
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
}
rcu_read_unlock();
......@@ -381,7 +381,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
* memory barriers as we'll eventually observe the right
* values at the cost of a few extra spins.
*/
arch_mutex_cpu_relax();
cpu_relax_lowlatency();
}
osq_unlock(&sem->osq);
done:
......
......@@ -835,7 +835,7 @@ config DEBUG_RT_MUTEXES
config RT_MUTEX_TESTER
bool "Built-in scriptable tester for rt-mutexes"
depends on DEBUG_KERNEL && RT_MUTEXES
depends on DEBUG_KERNEL && RT_MUTEXES && BROKEN
help
This option enables a rt-mutex tester.
......
#include <linux/export.h>
#include <linux/lockref.h>
#include <linux/mutex.h>
#if USE_CMPXCHG_LOCKREF
......@@ -29,7 +28,7 @@
if (likely(old.lock_count == prev.lock_count)) { \
SUCCESS; \
} \
arch_mutex_cpu_relax(); \
cpu_relax_lowlatency(); \
} \
} while (0)
......
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