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 tree got pretty big in this development cycle, but the net effect
is pretty good:
115 files changed, 673 insertions(+), 1522 deletions(-)
The main changes were:
- Rework and generalize the mutex code to remove per arch mutex
primitives. (Peter Zijlstra)
- Add vCPU preemption support: add an interface to query the
preemption status of vCPUs and use it in locking primitives - this
optimizes paravirt performance. (Pan Xinhui, Juergen Gross,
Christian Borntraeger)
- Introduce cpu_relax_yield() and remov cpu_relax_lowlatency() to
clean up and improve the s390 lock yielding machinery and its core
kernel impact. (Christian Borntraeger)
- Micro-optimize mutexes some more. (Waiman Long)
- Reluctantly add the to-be-deprecated mutex_trylock_recursive()
interface on a temporary basis, to give the DRM code more time to
get rid of its locking hacks. Any other users will be NAK-ed on
sight. (We turned off the deprecation warning for the time being to
not pollute the build log.) (Peter Zijlstra)
- Improve the rtmutex code a bit, in light of recent long lived
bugs/races. (Thomas Gleixner)
- Misc fixes, cleanups"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
x86/paravirt: Fix bool return type for PVOP_CALL()
x86/paravirt: Fix native_patch()
locking/ww_mutex: Use relaxed atomics
locking/rtmutex: Explain locking rules for rt_mutex_proxy_unlock()/init_proxy_locked()
locking/rtmutex: Get rid of RT_MUTEX_OWNER_MASKALL
x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted()
locking/mutex: Break out of expensive busy-loop on {mutex,rwsem}_spin_on_owner() when owner vCPU is preempted
locking/osq: Break out of spin-wait busy waiting loop for a preempted vCPU in osq_lock()
Documentation/virtual/kvm: Support the vCPU preemption check
x86/xen: Support the vCPU preemption check
x86/kvm: Support the vCPU preemption check
x86/kvm: Support the vCPU preemption check
kvm: Introduce kvm_write_guest_offset_cached()
locking/core, x86/paravirt: Implement vcpu_is_preempted(cpu) for KVM and Xen guests
locking/spinlocks, s390: Implement vcpu_is_preempted(cpu)
locking/core, powerpc: Implement vcpu_is_preempted(cpu)
sched/core: Introduce the vcpu_is_preempted(cpu) interface
sched/wake_q: Rename WAKE_Q to DEFINE_WAKE_Q
locking/core: Provide common cpu_relax_yield() definition
locking/mutex: Don't mark mutex_trylock_recursive() as deprecated, temporarily
...
This commit is contained in:
Linus Torvalds
@@ -1,132 +0,0 @@
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/*
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* Optimised mutex implementation of include/asm-generic/mutex-dec.h algorithm
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*/
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#ifndef _ASM_POWERPC_MUTEX_H
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#define _ASM_POWERPC_MUTEX_H
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static inline int __mutex_cmpxchg_lock(atomic_t *v, int old, int new)
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{
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int t;
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__asm__ __volatile__ (
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"1: lwarx %0,0,%1 # mutex trylock\n\
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cmpw 0,%0,%2\n\
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bne- 2f\n"
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PPC405_ERR77(0,%1)
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" stwcx. %3,0,%1\n\
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bne- 1b"
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PPC_ACQUIRE_BARRIER
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"\n\
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2:"
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: "=&r" (t)
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: "r" (&v->counter), "r" (old), "r" (new)
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: "cc", "memory");
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return t;
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}
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static inline int __mutex_dec_return_lock(atomic_t *v)
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{
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int t;
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__asm__ __volatile__(
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"1: lwarx %0,0,%1 # mutex lock\n\
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addic %0,%0,-1\n"
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PPC405_ERR77(0,%1)
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" stwcx. %0,0,%1\n\
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bne- 1b"
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PPC_ACQUIRE_BARRIER
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: "=&r" (t)
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: "r" (&v->counter)
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: "cc", "memory");
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return t;
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}
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static inline int __mutex_inc_return_unlock(atomic_t *v)
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{
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int t;
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__asm__ __volatile__(
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PPC_RELEASE_BARRIER
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"1: lwarx %0,0,%1 # mutex unlock\n\
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addic %0,%0,1\n"
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PPC405_ERR77(0,%1)
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" stwcx. %0,0,%1 \n\
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bne- 1b"
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: "=&r" (t)
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: "r" (&v->counter)
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: "cc", "memory");
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return t;
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}
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/**
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* __mutex_fastpath_lock - try to take the lock by moving the count
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* from 1 to a 0 value
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* @count: pointer of type atomic_t
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* @fail_fn: function to call if the original value was not 1
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*
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* Change the count from 1 to a value lower than 1, and call <fail_fn> if
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* it wasn't 1 originally. This function MUST leave the value lower than
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* 1 even when the "1" assertion wasn't true.
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*/
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static inline void
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__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
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{
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if (unlikely(__mutex_dec_return_lock(count) < 0))
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fail_fn(count);
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}
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/**
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* __mutex_fastpath_lock_retval - try to take the lock by moving the count
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* from 1 to a 0 value
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* @count: pointer of type atomic_t
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*
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* Change the count from 1 to a value lower than 1. This function returns 0
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* if the fastpath succeeds, or -1 otherwise.
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*/
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static inline int
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__mutex_fastpath_lock_retval(atomic_t *count)
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{
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if (unlikely(__mutex_dec_return_lock(count) < 0))
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return -1;
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return 0;
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}
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/**
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* __mutex_fastpath_unlock - try to promote the count from 0 to 1
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* @count: pointer of type atomic_t
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* @fail_fn: function to call if the original value was not 0
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*
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* Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
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* In the failure case, this function is allowed to either set the value to
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* 1, or to set it to a value lower than 1.
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*/
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static inline void
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__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
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{
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if (unlikely(__mutex_inc_return_unlock(count) <= 0))
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fail_fn(count);
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}
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#define __mutex_slowpath_needs_to_unlock() 1
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/**
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* __mutex_fastpath_trylock - try to acquire the mutex, without waiting
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*
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* @count: pointer of type atomic_t
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* @fail_fn: fallback function
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*
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* Change the count from 1 to 0, and return 1 (success), or if the count
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* was not 1, then return 0 (failure).
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*/
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static inline int
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__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
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{
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if (likely(atomic_read(count) == 1 && __mutex_cmpxchg_lock(count, 1, 0) == 1))
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return 1;
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return 0;
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}
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#endif
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@@ -404,8 +404,6 @@ static inline unsigned long __pack_fe01(unsigned int fpmode)
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#define cpu_relax() barrier()
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#endif
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#define cpu_relax_lowlatency() cpu_relax()
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/* Check that a certain kernel stack pointer is valid in task_struct p */
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int validate_sp(unsigned long sp, struct task_struct *p,
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unsigned long nbytes);
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@@ -52,6 +52,14 @@
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#define SYNC_IO
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#endif
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#ifdef CONFIG_PPC_PSERIES
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#define vcpu_is_preempted vcpu_is_preempted
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static inline bool vcpu_is_preempted(int cpu)
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{
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return !!(be32_to_cpu(lppaca_of(cpu).yield_count) & 1);
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}
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#endif
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static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock)
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{
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return lock.slock == 0;
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