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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:
 "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 2016-12-12 10:48:02 -08:00
commit 6cdf89b1ca
116 changed files with 678 additions and 1527 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
Documentation/virtual/kvm/msr.txt
View file

@ -208,7 +208,9 @@ MSR_KVM_STEAL_TIME: 0x4b564d03
__u64 steal;
__u32 version;
__u32 flags;
__u32 pad[12];
__u8 preempted;
__u8 u8_pad[3];
__u32 pad[11];
}
whose data will be filled in by the hypervisor periodically. Only one
@ -232,6 +234,11 @@ MSR_KVM_STEAL_TIME: 0x4b564d03
nanoseconds. Time during which the vcpu is idle, will not be
reported as steal time.
preempted: indicate the vCPU who owns this struct is running or
not. Non-zero values mean the vCPU has been preempted. Zero
means the vCPU is not preempted. NOTE, it is always zero if the
the hypervisor doesn't support this field.
MSR_KVM_EOI_EN: 0x4b564d04
data: Bit 0 is 1 when PV end of interrupt is enabled on the vcpu; 0
when disabled. Bit 1 is reserved and must be zero. When PV end of

9
arch/alpha/include/asm/mutex.h
View file

@ -1,9 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-dec.h>

1
arch/alpha/include/asm/processor.h
View file

@ -58,7 +58,6 @@ 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

18
arch/arc/include/asm/mutex.h
View file

@ -1,18 +0,0 @@
/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/*
* xchg() based mutex fast path maintains a state of 0 or 1, as opposed to
* atomic dec based which can "count" any number of lock contenders.
* This ideally needs to be fixed in core, but for now switching to dec ver.
*/
#if defined(CONFIG_SMP) && (CONFIG_NR_CPUS > 2)
#include <asm-generic/mutex-dec.h>
#else
#include <asm-generic/mutex-xchg.h>
#endif

3
arch/arc/include/asm/processor.h
View file

@ -60,15 +60,12 @@ struct task_struct;
#ifndef CONFIG_EZNPS_MTM_EXT
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#else
#define cpu_relax() \
__asm__ __volatile__ (".word %0" : : "i"(CTOP_INST_SCHD_RW) : "memory")
#define cpu_relax_lowlatency() barrier()
#endif
#define copy_segments(tsk, mm) do { } while (0)

21
arch/arm/include/asm/mutex.h
View file

@ -1,21 +0,0 @@
/*
* arch/arm/include/asm/mutex.h
*
* ARM optimized mutex locking primitives
*
* Please look into asm-generic/mutex-xchg.h for a formal definition.
*/
#ifndef _ASM_MUTEX_H
#define _ASM_MUTEX_H
/*
* On pre-ARMv6 hardware this results in a swp-based implementation,
* which is the most efficient. For ARMv6+, we have exclusive memory
* accessors and use atomic_dec to avoid the extra xchg operations
* on the locking slowpaths.
*/
#if __LINUX_ARM_ARCH__ < 6
#include <asm-generic/mutex-xchg.h>
#else
#include <asm-generic/mutex-dec.h>
#endif
#endif /* _ASM_MUTEX_H */

2
arch/arm/include/asm/processor.h
View file

@ -82,8 +82,6 @@ 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)

1
arch/arm64/include/asm/Kbuild
View file

@ -24,7 +24,6 @@ generic-y += mm-arch-hooks.h
generic-y += mman.h
generic-y += msgbuf.h
generic-y += msi.h
generic-y += mutex.h
generic-y += poll.h
generic-y += preempt.h
generic-y += resource.h

2
arch/arm64/include/asm/processor.h
View file

@ -149,8 +149,6 @@ static inline void cpu_relax(void)
asm volatile("yield" ::: "memory");
}
#define cpu_relax_lowlatency() cpu_relax()
/* Thread switching */
extern struct task_struct *cpu_switch_to(struct task_struct *prev,
struct task_struct *next);

9
arch/avr32/include/asm/mutex.h
View file

@ -1,9 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-dec.h>

1
arch/avr32/include/asm/processor.h
View file

@ -92,7 +92,6 @@ 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 {

1
arch/blackfin/include/asm/Kbuild
View file

@ -24,7 +24,6 @@ generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += mman.h
generic-y += msgbuf.h
generic-y += mutex.h
generic-y += param.h
generic-y += percpu.h
generic-y += pgalloc.h

1
arch/blackfin/include/asm/processor.h
View file

@ -92,7 +92,6 @@ 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)

6
arch/c6x/include/asm/mutex.h
View file

@ -1,6 +0,0 @@
#ifndef _ASM_C6X_MUTEX_H
#define _ASM_C6X_MUTEX_H
#include <asm-generic/mutex-null.h>
#endif /* _ASM_C6X_MUTEX_H */

1
arch/c6x/include/asm/processor.h
View file

@ -121,7 +121,6 @@ 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;

9
arch/cris/include/asm/mutex.h
View file

@ -1,9 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-dec.h>

1
arch/cris/include/asm/processor.h
View file

@ -63,7 +63,6 @@ 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);

9
arch/frv/include/asm/mutex.h
View file

@ -1,9 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-dec.h>

1
arch/frv/include/asm/processor.h
View file

@ -107,7 +107,6 @@ unsigned long get_wchan(struct task_struct *p);
#define KSTK_ESP(tsk) ((tsk)->thread.frame0->sp)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
/* data cache prefetch */
#define ARCH_HAS_PREFETCH

9
arch/h8300/include/asm/mutex.h
View file

@ -1,9 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-dec.h>

1
arch/h8300/include/asm/processor.h
View file

@ -127,7 +127,6 @@ unsigned long get_wchan(struct task_struct *p);
#define KSTK_ESP(tsk) ((tsk) == current ? rdusp() : (tsk)->thread.usp)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#define HARD_RESET_NOW() ({ \
local_irq_disable(); \

8
arch/hexagon/include/asm/mutex.h
View file

@ -1,8 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-xchg.h>

1
arch/hexagon/include/asm/processor.h
View file

@ -56,7 +56,6 @@ 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

90
arch/ia64/include/asm/mutex.h
View file

@ -1,90 +0,0 @@
/*
* ia64 implementation of the mutex fastpath.
*
* Copyright (C) 2006 Ken Chen <kenneth.w.chen@intel.com>
*
*/
#ifndef _ASM_MUTEX_H
#define _ASM_MUTEX_H
/**
* __mutex_fastpath_lock - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
* @fail_fn: function to call if the original value was not 1
*
* Change the count from 1 to a value lower than 1, and call <fail_fn> if
* it wasn't 1 originally. This function MUST leave the value lower than
* 1 even when the "1" assertion wasn't true.
*/
static inline void
__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
if (unlikely(ia64_fetchadd4_acq(count, -1) != 1))
fail_fn(count);
}
/**
* __mutex_fastpath_lock_retval - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
*
* Change the count from 1 to a value lower than 1. This function returns 0
* if the fastpath succeeds, or -1 otherwise.
*/
static inline int
__mutex_fastpath_lock_retval(atomic_t *count)
{
if (unlikely(ia64_fetchadd4_acq(count, -1) != 1))
return -1;
return 0;
}
/**
* __mutex_fastpath_unlock - try to promote the count from 0 to 1
* @count: pointer of type atomic_t
* @fail_fn: function to call if the original value was not 0
*
* Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
* In the failure case, this function is allowed to either set the value to
* 1, or to set it to a value lower than 1.
*
* If the implementation sets it to a value of lower than 1, then the
* __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
* to return 0 otherwise.
*/
static inline void
__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
int ret = ia64_fetchadd4_rel(count, 1);
if (unlikely(ret < 0))
fail_fn(count);
}
#define __mutex_slowpath_needs_to_unlock() 1
/**
* __mutex_fastpath_trylock - try to acquire the mutex, without waiting
*
* @count: pointer of type atomic_t
* @fail_fn: fallback function
*
* Change the count from 1 to a value lower than 1, and return 0 (failure)
* if it wasn't 1 originally, or return 1 (success) otherwise. This function
* MUST leave the value lower than 1 even when the "1" assertion wasn't true.
* Additionally, if the value was < 0 originally, this function must not leave
* it to 0 on failure.
*
* If the architecture has no effective trylock variant, it should call the
* <fail_fn> spinlock-based trylock variant unconditionally.
*/
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
if (atomic_read(count) == 1 && cmpxchg_acq(count, 1, 0) == 1)
return 1;
return 0;
}
#endif

1
arch/ia64/include/asm/processor.h
View file

@ -547,7 +547,6 @@ 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)

9
arch/m32r/include/asm/mutex.h
View file

@ -1,9 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-dec.h>

1
arch/m32r/include/asm/processor.h
View file

@ -133,6 +133,5 @@ 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 */

1
arch/m68k/include/asm/Kbuild
View file

@ -20,7 +20,6 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += mman.h
generic-y += mutex.h
generic-y += percpu.h
generic-y += preempt.h
generic-y += resource.h

1
arch/m68k/include/asm/processor.h
View file

@ -156,6 +156,5 @@ 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

1
arch/metag/include/asm/Kbuild
View file

@ -27,7 +27,6 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += msgbuf.h
generic-y += mutex.h
generic-y += param.h
generic-y += pci.h
generic-y += percpu.h

1
arch/metag/include/asm/processor.h
View file

@ -152,7 +152,6 @@ 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);

1
arch/microblaze/include/asm/mutex.h
View file

@ -1 +0,0 @@
#include <asm-generic/mutex-dec.h>

1
arch/microblaze/include/asm/processor.h
View file

@ -22,7 +22,6 @@
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)

1
arch/mips/include/asm/Kbuild
View file

@ -9,7 +9,6 @@ generic-y += irq_work.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += mutex.h
generic-y += parport.h
generic-y += percpu.h
generic-y += preempt.h

1
arch/mips/include/asm/processor.h
View file

@ -389,7 +389,6 @@ 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)

16
arch/mn10300/include/asm/mutex.h
View file

@ -1,16 +0,0 @@
/* MN10300 Mutex fastpath
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-null.h>

1
arch/mn10300/include/asm/processor.h
View file

@ -69,7 +69,6 @@ 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).

1
arch/nios2/include/asm/mutex.h
View file

@ -1 +0,0 @@
#include <asm-generic/mutex-dec.h>

1
arch/nios2/include/asm/processor.h
View file

@ -88,7 +88,6 @@ extern unsigned long get_wchan(struct task_struct *p);
#define KSTK_ESP(tsk) ((tsk)->thread.kregs->sp)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#endif /* __ASSEMBLY__ */

27
arch/openrisc/include/asm/mutex.h
View file

@ -1,27 +0,0 @@
/*
* OpenRISC Linux
*
* Linux architectural port borrowing liberally from similar works of
* others. All original copyrights apply as per the original source
* declaration.
*
* OpenRISC implementation:
* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
* et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-dec.h>

1
arch/openrisc/include/asm/processor.h
View file

@ -92,7 +92,6 @@ 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 */

1
arch/parisc/include/asm/Kbuild
View file

@ -16,7 +16,6 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += mutex.h
generic-y += param.h
generic-y += percpu.h
generic-y += poll.h

1
arch/parisc/include/asm/processor.h
View file

@ -309,7 +309,6 @@ 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()
/*
* parisc_requires_coherency() is used to identify the combined VIPT/PIPT

132
arch/powerpc/include/asm/mutex.h
View file

@ -1,132 +0,0 @@
/*
* Optimised mutex implementation of include/asm-generic/mutex-dec.h algorithm
*/
#ifndef _ASM_POWERPC_MUTEX_H
#define _ASM_POWERPC_MUTEX_H
static inline int __mutex_cmpxchg_lock(atomic_t *v, int old, int new)
{
int t;
__asm__ __volatile__ (
"1: lwarx %0,0,%1 # mutex trylock\n\
cmpw 0,%0,%2\n\
bne- 2f\n"
PPC405_ERR77(0,%1)
" stwcx. %3,0,%1\n\
bne- 1b"
PPC_ACQUIRE_BARRIER
"\n\
2:"
: "=&r" (t)
: "r" (&v->counter), "r" (old), "r" (new)
: "cc", "memory");
return t;
}
static inline int __mutex_dec_return_lock(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%1 # mutex lock\n\
addic %0,%0,-1\n"
PPC405_ERR77(0,%1)
" stwcx. %0,0,%1\n\
bne- 1b"
PPC_ACQUIRE_BARRIER
: "=&r" (t)
: "r" (&v->counter)
: "cc", "memory");
return t;
}
static inline int __mutex_inc_return_unlock(atomic_t *v)
{
int t;
__asm__ __volatile__(
PPC_RELEASE_BARRIER
"1: lwarx %0,0,%1 # mutex unlock\n\
addic %0,%0,1\n"
PPC405_ERR77(0,%1)
" stwcx. %0,0,%1 \n\
bne- 1b"
: "=&r" (t)
: "r" (&v->counter)
: "cc", "memory");
return t;
}
/**
* __mutex_fastpath_lock - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
* @fail_fn: function to call if the original value was not 1
*
* Change the count from 1 to a value lower than 1, and call <fail_fn> if
* it wasn't 1 originally. This function MUST leave the value lower than
* 1 even when the "1" assertion wasn't true.
*/
static inline void
__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
if (unlikely(__mutex_dec_return_lock(count) < 0))
fail_fn(count);
}
/**
* __mutex_fastpath_lock_retval - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
*
* Change the count from 1 to a value lower than 1. This function returns 0
* if the fastpath succeeds, or -1 otherwise.
*/
static inline int
__mutex_fastpath_lock_retval(atomic_t *count)
{
if (unlikely(__mutex_dec_return_lock(count) < 0))
return -1;
return 0;
}
/**
* __mutex_fastpath_unlock - try to promote the count from 0 to 1
* @count: pointer of type atomic_t
* @fail_fn: function to call if the original value was not 0
*
* Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
* In the failure case, this function is allowed to either set the value to
* 1, or to set it to a value lower than 1.
*/
static inline void
__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
if (unlikely(__mutex_inc_return_unlock(count) <= 0))
fail_fn(count);
}
#define __mutex_slowpath_needs_to_unlock() 1
/**
* __mutex_fastpath_trylock - try to acquire the mutex, without waiting
*
* @count: pointer of type atomic_t
* @fail_fn: fallback function
*
* Change the count from 1 to 0, and return 1 (success), or if the count
* was not 1, then return 0 (failure).
*/
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
if (likely(atomic_read(count) == 1 && __mutex_cmpxchg_lock(count, 1, 0) == 1))
return 1;
return 0;
}
#endif

2
arch/powerpc/include/asm/processor.h
View file

@ -404,8 +404,6 @@ 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);

8
arch/powerpc/include/asm/spinlock.h
View file

@ -52,6 +52,14 @@
#define SYNC_IO
#endif
#ifdef CONFIG_PPC_PSERIES
#define vcpu_is_preempted vcpu_is_preempted
static inline bool vcpu_is_preempted(int cpu)
{
return !!(be32_to_cpu(lppaca_of(cpu).yield_count) & 1);
}
#endif
static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock)
{
return lock.slock == 0;

9
arch/s390/include/asm/mutex.h
View file

@ -1,9 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-dec.h>

5
arch/s390/include/asm/processor.h
View file

@ -234,9 +234,10 @@ static inline unsigned short stap(void)
/*
* Give up the time slice of the virtual PU.
*/
void cpu_relax(void);
#define cpu_relax_yield cpu_relax_yield
void cpu_relax_yield(void);
#define cpu_relax_lowlatency() barrier()
#define cpu_relax() barrier()
#define ECAG_CACHE_ATTRIBUTE 0
#define ECAG_CPU_ATTRIBUTE 1

8
arch/s390/include/asm/spinlock.h
View file

@ -23,6 +23,14 @@ _raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new)
return __sync_bool_compare_and_swap(lock, old, new);
}
#ifndef CONFIG_SMP
static inline bool arch_vcpu_is_preempted(int cpu) { return false; }
#else
bool arch_vcpu_is_preempted(int cpu);
#endif
#define vcpu_is_preempted arch_vcpu_is_preempted
/*
* Simple spin lock operations. There are two variants, one clears IRQ's
* on the local processor, one does not.

4
arch/s390/kernel/processor.c
View file

@ -53,7 +53,7 @@ void s390_update_cpu_mhz(void)
on_each_cpu(update_cpu_mhz, NULL, 0);
}
void notrace cpu_relax(void)
void notrace cpu_relax_yield(void)
{
if (!smp_cpu_mtid && MACHINE_HAS_DIAG44) {
diag_stat_inc(DIAG_STAT_X044);
@ -61,7 +61,7 @@ void notrace cpu_relax(void)
}
barrier();
}
EXPORT_SYMBOL(cpu_relax);
EXPORT_SYMBOL(cpu_relax_yield);
/*
* cpu_init - initializes state that is per-CPU.

9
arch/s390/kernel/smp.c
View file

@ -368,10 +368,15 @@ int smp_find_processor_id(u16 address)
return -1;
}
int smp_vcpu_scheduled(int cpu)
bool arch_vcpu_is_preempted(int cpu)
{
return pcpu_running(pcpu_devices + cpu);
if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
return false;
if (pcpu_running(pcpu_devices + cpu))
return false;
return true;
}
EXPORT_SYMBOL(arch_vcpu_is_preempted);
void smp_yield_cpu(int cpu)
{

25
arch/s390/lib/spinlock.c
View file

@ -37,15 +37,6 @@ static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old)
asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock));
}
static inline int cpu_is_preempted(int cpu)
{
if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
return 0;
if (smp_vcpu_scheduled(cpu))
return 0;
return 1;
}
void arch_spin_lock_wait(arch_spinlock_t *lp)
{
unsigned int cpu = SPINLOCK_LOCKVAL;
@ -62,7 +53,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
continue;
}
/* First iteration: check if the lock owner is running. */
if (first_diag && cpu_is_preempted(~owner)) {
if (first_diag && arch_vcpu_is_preempted(~owner)) {
smp_yield_cpu(~owner);
first_diag = 0;
continue;
@ -81,7 +72,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
* yield the CPU unconditionally. For LPAR rely on the
* sense running status.
*/
if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) {
if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) {
smp_yield_cpu(~owner);
first_diag = 0;
}
@ -108,7 +99,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
continue;
}
/* Check if the lock owner is running. */
if (first_diag && cpu_is_preempted(~owner)) {
if (first_diag && arch_vcpu_is_preempted(~owner)) {
smp_yield_cpu(~owner);
first_diag = 0;
continue;
@ -127,7 +118,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
* yield the CPU unconditionally. For LPAR rely on the
* sense running status.
*/
if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) {
if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) {
smp_yield_cpu(~owner);
first_diag = 0;
}
@ -165,7 +156,7 @@ void _raw_read_lock_wait(arch_rwlock_t *rw)
owner = 0;
while (1) {
if (count-- <= 0) {
if (owner && cpu_is_preempted(~owner))
if (owner && arch_vcpu_is_preempted(~owner))
smp_yield_cpu(~owner);
count = spin_retry;
}
@ -211,7 +202,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev)
owner = 0;
while (1) {
if (count-- <= 0) {
if (owner && cpu_is_preempted(~owner))
if (owner && arch_vcpu_is_preempted(~owner))
smp_yield_cpu(~owner);
count = spin_retry;
}
@ -241,7 +232,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw)
owner = 0;
while (1) {
if (count-- <= 0) {
if (owner && cpu_is_preempted(~owner))
if (owner && arch_vcpu_is_preempted(~owner))
smp_yield_cpu(~owner);
count = spin_retry;
}
@ -285,7 +276,7 @@ void arch_lock_relax(unsigned int cpu)
{
if (!cpu)
return;
if (MACHINE_IS_LPAR && !cpu_is_preempted(~cpu))
if (MACHINE_IS_LPAR && !arch_vcpu_is_preempted(~cpu))
return;
smp_yield_cpu(~cpu);
}

6
arch/score/include/asm/mutex.h
View file

@ -1,6 +0,0 @@
#ifndef _ASM_SCORE_MUTEX_H
#define _ASM_SCORE_MUTEX_H
#include <asm-generic/mutex-dec.h>
#endif /* _ASM_SCORE_MUTEX_H */

1
arch/score/include/asm/processor.h
View file

@ -24,7 +24,6 @@ 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)
/*

109
arch/sh/include/asm/mutex-llsc.h
View file

@ -1,109 +0,0 @@
/*
* arch/sh/include/asm/mutex-llsc.h
*
* SH-4A optimized mutex locking primitives
*
* Please look into asm-generic/mutex-xchg.h for a formal definition.
*/
#ifndef __ASM_SH_MUTEX_LLSC_H
#define __ASM_SH_MUTEX_LLSC_H
/*
* Attempting to lock a mutex on SH4A is done like in ARMv6+ architecure.
* with a bastardized atomic decrement (it is not a reliable atomic decrement
* but it satisfies the defined semantics for our purpose, while being
* smaller and faster than a real atomic decrement or atomic swap.
* The idea is to attempt decrementing the lock value only once. If once
* decremented it isn't zero, or if its store-back fails due to a dispute
* on the exclusive store, we simply bail out immediately through the slow
* path where the lock will be reattempted until it succeeds.
*/
static inline void
__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
int __done, __res;
__asm__ __volatile__ (
"movli.l @%2, %0 \n"
"add #-1, %0 \n"
"movco.l %0, @%2 \n"
"movt %1 \n"
: "=&z" (__res), "=&r" (__done)
: "r" (&(count)->counter)
: "t");
if (unlikely(!__done || __res != 0))
fail_fn(count);
}
static inline int
__mutex_fastpath_lock_retval(atomic_t *count)
{
int __done, __res;
__asm__ __volatile__ (
"movli.l @%2, %0 \n"
"add #-1, %0 \n"
"movco.l %0, @%2 \n"
"movt %1 \n"
: "=&z" (__res), "=&r" (__done)
: "r" (&(count)->counter)
: "t");
if (unlikely(!__done || __res != 0))
__res = -1;
return __res;
}
static inline void
__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
int __done, __res;
__asm__ __volatile__ (
"movli.l @%2, %0 \n\t"
"add #1, %0 \n\t"
"movco.l %0, @%2 \n\t"
"movt %1 \n\t"
: "=&z" (__res), "=&r" (__done)
: "r" (&(count)->counter)
: "t");
if (unlikely(!__done || __res <= 0))
fail_fn(count);
}
/*
* If the unlock was done on a contended lock, or if the unlock simply fails
* then the mutex remains locked.
*/
#define __mutex_slowpath_needs_to_unlock() 1
/*
* For __mutex_fastpath_trylock we do an atomic decrement and check the
* result and put it in the __res variable.
*/
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
int __res, __orig;
__asm__ __volatile__ (
"1: movli.l @%2, %0 \n\t"
"dt %0 \n\t"
"movco.l %0,@%2 \n\t"
"bf 1b \n\t"
"cmp/eq #0,%0 \n\t"
"bt 2f \n\t"
"mov #0, %1 \n\t"
"bf 3f \n\t"
"2: mov #1, %1 \n\t"
"3: "
: "=&z" (__orig), "=&r" (__res)
: "r" (&count->counter)
: "t");
return __res;
}
#endif /* __ASM_SH_MUTEX_LLSC_H */

12
arch/sh/include/asm/mutex.h
View file

@ -1,12 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#if defined(CONFIG_CPU_SH4A)
#include <asm/mutex-llsc.h>
#else
#include <asm-generic/mutex-dec.h>
#endif

1
arch/sh/include/asm/processor.h
View file

@ -97,7 +97,6 @@ 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 *);

1
arch/sparc/include/asm/Kbuild
View file

@ -15,7 +15,6 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += module.h
generic-y += mutex.h
generic-y += preempt.h
generic-y += rwsem.h
generic-y += serial.h

1
arch/sparc/include/asm/processor_32.h
View file

@ -119,7 +119,6 @@ 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);

1
arch/sparc/include/asm/processor_64.h
View file

@ -216,7 +216,6 @@ 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

1
arch/tile/include/asm/Kbuild
View file

@ -21,7 +21,6 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += msgbuf.h
generic-y += mutex.h
generic-y += param.h
generic-y += parport.h
generic-y += poll.h

2
arch/tile/include/asm/processor.h
View file

@ -264,8 +264,6 @@ 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;

1
arch/um/include/asm/Kbuild
View file

@ -17,7 +17,6 @@ generic-y += irq_work.h
generic-y += kdebug.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += mutex.h
generic-y += param.h
generic-y += pci.h
generic-y += percpu.h

20
arch/unicore32/include/asm/mutex.h
View file

@ -1,20 +0,0 @@
/*
* linux/arch/unicore32/include/asm/mutex.h
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Copyright (C) 2001-2010 GUAN Xue-tao
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* UniCore optimized mutex locking primitives
*
* Please look into asm-generic/mutex-xchg.h for a formal definition.
*/
#ifndef __UNICORE_MUTEX_H__
#define __UNICORE_MUTEX_H__
# include <asm-generic/mutex-xchg.h>
#endif

1
arch/unicore32/include/asm/processor.h
View file

@ -71,7 +71,6 @@ 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)

5
arch/x86/include/asm/mutex.h
View file

@ -1,5 +0,0 @@
#ifdef CONFIG_X86_32
# include <asm/mutex_32.h>
#else
# include <asm/mutex_64.h>
#endif

110
arch/x86/include/asm/mutex_32.h
View file

@ -1,110 +0,0 @@
/*
* Assembly implementation of the mutex fastpath, based on atomic
* decrement/increment.
*
* started by Ingo Molnar:
*
* Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
#ifndef _ASM_X86_MUTEX_32_H
#define _ASM_X86_MUTEX_32_H
#include <asm/alternative.h>
/**
* __mutex_fastpath_lock - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
* @fn: function to call if the original value was not 1
*
* Change the count from 1 to a value lower than 1, and call <fn> if it
* wasn't 1 originally. This function MUST leave the value lower than 1
* even when the "1" assertion wasn't true.
*/
#define __mutex_fastpath_lock(count, fail_fn) \
do { \
unsigned int dummy; \
\
typecheck(atomic_t *, count); \
typecheck_fn(void (*)(atomic_t *), fail_fn); \
\
asm volatile(LOCK_PREFIX " decl (%%eax)\n" \
" jns 1f \n" \
" call " #fail_fn "\n" \
"1:\n" \
: "=a" (dummy) \
: "a" (count) \
: "memory", "ecx", "edx"); \
} while (0)
/**
* __mutex_fastpath_lock_retval - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
*
* Change the count from 1 to a value lower than 1. This function returns 0
* if the fastpath succeeds, or -1 otherwise.
*/
static inline int __mutex_fastpath_lock_retval(atomic_t *count)
{
if (unlikely(atomic_dec_return(count) < 0))
return -1;
else
return 0;
}
/**
* __mutex_fastpath_unlock - try to promote the mutex from 0 to 1
* @count: pointer of type atomic_t
* @fail_fn: function to call if the original value was not 0
*
* try to promote the mutex from 0 to 1. if it wasn't 0, call <fail_fn>.
* In the failure case, this function is allowed to either set the value
* to 1, or to set it to a value lower than 1.
*
* If the implementation sets it to a value of lower than 1, the
* __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
* to return 0 otherwise.
*/
#define __mutex_fastpath_unlock(count, fail_fn) \
do { \
unsigned int dummy; \
\
typecheck(atomic_t *, count); \
typecheck_fn(void (*)(atomic_t *), fail_fn); \
\
asm volatile(LOCK_PREFIX " incl (%%eax)\n" \
" jg 1f\n" \
" call " #fail_fn "\n" \
"1:\n" \
: "=a" (dummy) \
: "a" (count) \
: "memory", "ecx", "edx"); \
} while (0)
#define __mutex_slowpath_needs_to_unlock() 1
/**
* __mutex_fastpath_trylock - try to acquire the mutex, without waiting
*
* @count: pointer of type atomic_t
* @fail_fn: fallback function
*
* Change the count from 1 to a value lower than 1, and return 0 (failure)
* if it wasn't 1 originally, or return 1 (success) otherwise. This function
* MUST leave the value lower than 1 even when the "1" assertion wasn't true.
* Additionally, if the value was < 0 originally, this function must not leave
* it to 0 on failure.
*/
static inline int __mutex_fastpath_trylock(atomic_t *count,
int (*fail_fn)(atomic_t *))
{
/* cmpxchg because it never induces a false contention state. */
if (likely(atomic_read(count) == 1 && atomic_cmpxchg(count, 1, 0) == 1))
return 1;
return 0;
}
#endif /* _ASM_X86_MUTEX_32_H */

127
arch/x86/include/asm/mutex_64.h
View file

@ -1,127 +0,0 @@
/*
* Assembly implementation of the mutex fastpath, based on atomic
* decrement/increment.
*
* started by Ingo Molnar:
*
* Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
#ifndef _ASM_X86_MUTEX_64_H
#define _ASM_X86_MUTEX_64_H
/**
* __mutex_fastpath_lock - decrement and call function if negative
* @v: pointer of type atomic_t
* @fail_fn: function to call if the result is negative
*
* Atomically decrements @v and calls <fail_fn> if the result is negative.
*/
#ifdef CC_HAVE_ASM_GOTO
static inline void __mutex_fastpath_lock(atomic_t *v,
void (*fail_fn)(atomic_t *))
{
asm_volatile_goto(LOCK_PREFIX " decl %0\n"
" jns %l[exit]\n"
: : "m" (v->counter)
: "memory", "cc"
: exit);
fail_fn(v);
exit:
return;
}
#else
#define __mutex_fastpath_lock(v, fail_fn) \
do { \
unsigned long dummy; \
\
typecheck(atomic_t *, v); \
typecheck_fn(void (*)(atomic_t *), fail_fn); \
\
asm volatile(LOCK_PREFIX " decl (%%rdi)\n" \
" jns 1f \n" \
" call " #fail_fn "\n" \
"1:" \
: "=D" (dummy) \
: "D" (v) \
: "rax", "rsi", "rdx", "rcx", \
"r8", "r9", "r10", "r11", "memory"); \
} while (0)
#endif
/**
* __mutex_fastpath_lock_retval - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
*
* Change the count from 1 to a value lower than 1. This function returns 0
* if the fastpath succeeds, or -1 otherwise.
*/
static inline int __mutex_fastpath_lock_retval(atomic_t *count)
{
if (unlikely(atomic_dec_return(count) < 0))
return -1;
else
return 0;
}
/**
* __mutex_fastpath_unlock - increment and call function if nonpositive
* @v: pointer of type atomic_t
* @fail_fn: function to call if the result is nonpositive
*
* Atomically increments @v and calls <fail_fn> if the result is nonpositive.
*/
#ifdef CC_HAVE_ASM_GOTO
static inline void __mutex_fastpath_unlock(atomic_t *v,
void (*fail_fn)(atomic_t *))
{
asm_volatile_goto(LOCK_PREFIX " incl %0\n"
" jg %l[exit]\n"
: : "m" (v->counter)
: "memory", "cc"
: exit);
fail_fn(v);
exit:
return;
}
#else
#define __mutex_fastpath_unlock(v, fail_fn) \
do { \
unsigned long dummy; \
\
typecheck(atomic_t *, v); \
typecheck_fn(void (*)(atomic_t *), fail_fn); \
\
asm volatile(LOCK_PREFIX " incl (%%rdi)\n" \
" jg 1f\n" \
" call " #fail_fn "\n" \
"1:" \
: "=D" (dummy) \
: "D" (v) \
: "rax", "rsi", "rdx", "rcx", \
"r8", "r9", "r10", "r11", "memory"); \
} while (0)
#endif
#define __mutex_slowpath_needs_to_unlock() 1
/**
* __mutex_fastpath_trylock - try to acquire the mutex, without waiting
*
* @count: pointer of type atomic_t
* @fail_fn: fallback function
*
* Change the count from 1 to 0 and return 1 (success), or return 0 (failure)
* if it wasn't 1 originally. [the fallback function is never used on
* x86_64, because all x86_64 CPUs have a CMPXCHG instruction.]
*/
static inline int __mutex_fastpath_trylock(atomic_t *count,
int (*fail_fn)(atomic_t *))
{
if (likely(atomic_read(count) == 1 && atomic_cmpxchg(count, 1, 0) == 1))
return 1;
return 0;
}
#endif /* _ASM_X86_MUTEX_64_H */

5
arch/x86/include/asm/paravirt.h
View file

@ -678,6 +678,11 @@ static __always_inline void pv_kick(int cpu)
PVOP_VCALL1(pv_lock_ops.kick, cpu);
}
static __always_inline bool pv_vcpu_is_preempted(int cpu)
{
return PVOP_CALLEE1(bool, pv_lock_ops.vcpu_is_preempted, cpu);
}
#endif /* SMP && PARAVIRT_SPINLOCKS */
#ifdef CONFIG_X86_32

16
arch/x86/include/asm/paravirt_types.h
View file

@ -310,6 +310,8 @@ struct pv_lock_ops {
void (*wait)(u8 *ptr, u8 val);
void (*kick)(int cpu);
struct paravirt_callee_save vcpu_is_preempted;
};
/* This contains all the paravirt structures: we get a convenient
@ -508,6 +510,18 @@ int paravirt_disable_iospace(void);
#define PVOP_TEST_NULL(op) ((void)op)
#endif
#define PVOP_RETMASK(rettype) \
({ unsigned long __mask = ~0UL; \
switch (sizeof(rettype)) { \
case 1: __mask = 0xffUL; break; \
case 2: __mask = 0xffffUL; break; \
case 4: __mask = 0xffffffffUL; break; \
default: break; \
} \
__mask; \
})
#define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr, \
pre, post, ...) \
({ \
@ -535,7 +549,7 @@ int paravirt_disable_iospace(void);
paravirt_clobber(clbr), \
##__VA_ARGS__ \
: "memory", "cc" extra_clbr); \
__ret = (rettype)__eax; \
__ret = (rettype)(__eax & PVOP_RETMASK(rettype)); \
} \
__ret; \
})

2
arch/x86/include/asm/processor.h
View file

@ -588,8 +588,6 @@ static __always_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)
{

6
arch/x86/include/asm/qspinlock.h
View file

@ -32,6 +32,12 @@ static inline void queued_spin_unlock(struct qspinlock *lock)
{
pv_queued_spin_unlock(lock);
}
#define vcpu_is_preempted vcpu_is_preempted
static inline bool vcpu_is_preempted(int cpu)
{
return pv_vcpu_is_preempted(cpu);
}
#else
static inline void queued_spin_unlock(struct qspinlock *lock)
{

4
arch/x86/include/uapi/asm/kvm_para.h
View file

@ -45,7 +45,9 @@ struct kvm_steal_time {
__u64 steal;
__u32 version;
__u32 flags;
__u32 pad[12];
__u8 preempted;
__u8 u8_pad[3];
__u32 pad[11];
};
#define KVM_STEAL_ALIGNMENT_BITS 5

13
arch/x86/kernel/kvm.c
View file

@ -592,6 +592,14 @@ static void kvm_wait(u8 *ptr, u8 val)
local_irq_restore(flags);
}
__visible bool __kvm_vcpu_is_preempted(int cpu)
{
struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
return !!src->preempted;
}
PV_CALLEE_SAVE_REGS_THUNK(__kvm_vcpu_is_preempted);
/*
* Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
*/
@ -608,6 +616,11 @@ void __init kvm_spinlock_init(void)
pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock);
pv_lock_ops.wait = kvm_wait;
pv_lock_ops.kick = kvm_kick_cpu;
if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
pv_lock_ops.vcpu_is_preempted =
PV_CALLEE_SAVE(__kvm_vcpu_is_preempted);
}
}
static __init int kvm_spinlock_init_jump(void)

14
arch/x86/kernel/paravirt-spinlocks.c
View file

@ -12,7 +12,6 @@ __visible void __native_queued_spin_unlock(struct qspinlock *lock)
{
native_queued_spin_unlock(lock);
}
PV_CALLEE_SAVE_REGS_THUNK(__native_queued_spin_unlock);
bool pv_is_native_spin_unlock(void)
@ -21,12 +20,25 @@ bool pv_is_native_spin_unlock(void)
__raw_callee_save___native_queued_spin_unlock;
}
__visible bool __native_vcpu_is_preempted(int cpu)
{
return false;
}
PV_CALLEE_SAVE_REGS_THUNK(__native_vcpu_is_preempted);
bool pv_is_native_vcpu_is_preempted(void)
{
return pv_lock_ops.vcpu_is_preempted.func ==
__raw_callee_save___native_vcpu_is_preempted;
}
struct pv_lock_ops pv_lock_ops = {
#ifdef CONFIG_SMP
.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
.queued_spin_unlock = PV_CALLEE_SAVE(__native_queued_spin_unlock),
.wait = paravirt_nop,
.kick = paravirt_nop,
.vcpu_is_preempted = PV_CALLEE_SAVE(__native_vcpu_is_preempted),
#endif /* SMP */
};
EXPORT_SYMBOL(pv_lock_ops);

12
arch/x86/kernel/paravirt_patch_32.c
View file

@ -12,6 +12,7 @@ DEF_NATIVE(pv_cpu_ops, clts, "clts");
#if defined(CONFIG_PARAVIRT_SPINLOCKS)
DEF_NATIVE(pv_lock_ops, queued_spin_unlock, "movb $0, (%eax)");
DEF_NATIVE(pv_lock_ops, vcpu_is_preempted, "xor %eax, %eax");
#endif
unsigned paravirt_patch_ident_32(void *insnbuf, unsigned len)
@ -27,6 +28,7 @@ unsigned paravirt_patch_ident_64(void *insnbuf, unsigned len)
}
extern bool pv_is_native_spin_unlock(void);
extern bool pv_is_native_vcpu_is_preempted(void);
unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
unsigned long addr, unsigned len)
@ -56,9 +58,19 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
end = end_pv_lock_ops_queued_spin_unlock;
goto patch_site;
}
goto patch_default;
case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
if (pv_is_native_vcpu_is_preempted()) {
start = start_pv_lock_ops_vcpu_is_preempted;
end = end_pv_lock_ops_vcpu_is_preempted;
goto patch_site;
}
goto patch_default;
#endif
default:
patch_default:
ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
break;

12
arch/x86/kernel/paravirt_patch_64.c
View file

@ -21,6 +21,7 @@ DEF_NATIVE(, mov64, "mov %rdi, %rax");
#if defined(CONFIG_PARAVIRT_SPINLOCKS)
DEF_NATIVE(pv_lock_ops, queued_spin_unlock, "movb $0, (%rdi)");
DEF_NATIVE(pv_lock_ops, vcpu_is_preempted, "xor %rax, %rax");
#endif
unsigned paravirt_patch_ident_32(void *insnbuf, unsigned len)
@ -36,6 +37,7 @@ unsigned paravirt_patch_ident_64(void *insnbuf, unsigned len)
}
extern bool pv_is_native_spin_unlock(void);
extern bool pv_is_native_vcpu_is_preempted(void);
unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
unsigned long addr, unsigned len)
@ -68,9 +70,19 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
end = end_pv_lock_ops_queued_spin_unlock;
goto patch_site;
}
goto patch_default;
case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
if (pv_is_native_vcpu_is_preempted()) {
start = start_pv_lock_ops_vcpu_is_preempted;
end = end_pv_lock_ops_vcpu_is_preempted;
goto patch_site;
}
goto patch_default;
#endif
default:
patch_default:
ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
break;

16
arch/x86/kvm/x86.c
View file

@ -2071,6 +2071,8 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
&vcpu->arch.st.steal, sizeof(struct kvm_steal_time))))
return;
vcpu->arch.st.steal.preempted = 0;
if (vcpu->arch.st.steal.version & 1)
vcpu->arch.st.steal.version += 1; /* first time write, random junk */
@ -2826,8 +2828,22 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
}
static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu)
{
if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
return;
vcpu->arch.st.steal.preempted = 1;
kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime,
&vcpu->arch.st.steal.preempted,
offsetof(struct kvm_steal_time, preempted),
sizeof(vcpu->arch.st.steal.preempted));
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
kvm_steal_time_set_preempted(vcpu);
kvm_x86_ops->vcpu_put(vcpu);
kvm_put_guest_fpu(vcpu);
vcpu->arch.last_host_tsc = rdtsc();

1
arch/x86/um/asm/processor.h
View file

@ -26,7 +26,6 @@ static inline void rep_nop(void)
}
#define cpu_relax() rep_nop()
#define cpu_relax_lowlatency() cpu_relax()
#define task_pt_regs(t) (&(t)->thread.regs)

2
arch/x86/xen/spinlock.c
View file

@ -114,6 +114,7 @@ void xen_uninit_lock_cpu(int cpu)
per_cpu(irq_name, cpu) = NULL;
}
PV_CALLEE_SAVE_REGS_THUNK(xen_vcpu_stolen);
/*
* Our init of PV spinlocks is split in two init functions due to us
@ -137,6 +138,7 @@ void __init xen_init_spinlocks(void)
pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock);
pv_lock_ops.wait = xen_qlock_wait;
pv_lock_ops.kick = xen_qlock_kick;
pv_lock_ops.vcpu_is_preempted = PV_CALLEE_SAVE(xen_vcpu_stolen);
}
/*

9
arch/xtensa/include/asm/mutex.h
View file

@ -1,9 +0,0 @@
/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*/
#include <asm-generic/mutex-dec.h>

1
arch/xtensa/include/asm/processor.h
View file

@ -206,7 +206,6 @@ 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. */

2
drivers/gpu/drm/i915/i915_gem_request.c
View file

@ -723,7 +723,7 @@ bool __i915_spin_request(const struct drm_i915_gem_request *req,
if (busywait_stop(timeout_us, cpu))
break;
cpu_relax_lowlatency();
cpu_relax();
} while (!need_resched());
return false;

30
drivers/gpu/drm/i915/i915_gem_shrinker.c
View file

@ -35,19 +35,6 @@
#include "i915_drv.h"
#include "i915_trace.h"
static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
{
if (!mutex_is_locked(mutex))
return false;
#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER)
return mutex->owner == task;
#else
/* Since UP may be pre-empted, we cannot assume that we own the lock */
return false;
#endif
}
static bool any_vma_pinned(struct drm_i915_gem_object *obj)
{
struct i915_vma *vma;
@ -240,15 +227,20 @@ unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
{
if (!mutex_trylock(&dev->struct_mutex)) {
if (!mutex_is_locked_by(&dev->struct_mutex, current))
return false;
switch (mutex_trylock_recursive(&dev->struct_mutex)) {
case MUTEX_TRYLOCK_FAILED:
return false;
*unlock = false;
} else
case MUTEX_TRYLOCK_SUCCESS:
*unlock = true;
return true;
return true;
case MUTEX_TRYLOCK_RECURSIVE:
*unlock = false;
return true;
}
BUG();
}
static unsigned long

31
drivers/gpu/drm/msm/msm_gem_shrinker.c
View file

@ -18,33 +18,24 @@
#include "msm_drv.h"
#include "msm_gem.h"
static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
{
if (!mutex_is_locked(mutex))
return false;
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_MUTEXES)
return mutex->owner == task;
#else
/* Since UP may be pre-empted, we cannot assume that we own the lock */
return false;
#endif
}
static bool msm_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
{
if (!mutex_trylock(&dev->struct_mutex)) {
if (!mutex_is_locked_by(&dev->struct_mutex, current))
return false;
*unlock = false;
} else {
switch (mutex_trylock_recursive(&dev->struct_mutex)) {
case MUTEX_TRYLOCK_FAILED:
return false;
case MUTEX_TRYLOCK_SUCCESS:
*unlock = true;
return true;
case MUTEX_TRYLOCK_RECURSIVE:
*unlock = false;
return true;
}
return true;
BUG();
}
static unsigned long
msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
{

4
drivers/vhost/net.c
View file

@ -342,7 +342,7 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
endtime = busy_clock() + vq->busyloop_timeout;
while (vhost_can_busy_poll(vq->dev, endtime) &&
vhost_vq_avail_empty(vq->dev, vq))
cpu_relax_lowlatency();
cpu_relax();
preempt_enable();
r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
out_num, in_num, NULL, NULL);
@ -533,7 +533,7 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk)
while (vhost_can_busy_poll(&net->dev, endtime) &&
!sk_has_rx_data(sk) &&
vhost_vq_avail_empty(&net->dev, vq))
cpu_relax_lowlatency();
cpu_relax();
preempt_enable();

88
include/asm-generic/mutex-dec.h
View file

@ -1,88 +0,0 @@
/*
* include/asm-generic/mutex-dec.h
*
* Generic implementation of the mutex fastpath, based on atomic
* decrement/increment.
*/
#ifndef _ASM_GENERIC_MUTEX_DEC_H
#define _ASM_GENERIC_MUTEX_DEC_H
/**
* __mutex_fastpath_lock - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
* @fail_fn: function to call if the original value was not 1
*
* Change the count from 1 to a value lower than 1, and call <fail_fn> if
* it wasn't 1 originally. This function MUST leave the value lower than
* 1 even when the "1" assertion wasn't true.
*/
static inline void
__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
if (unlikely(atomic_dec_return_acquire(count) < 0))
fail_fn(count);
}
/**
* __mutex_fastpath_lock_retval - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
*
* Change the count from 1 to a value lower than 1. This function returns 0
* if the fastpath succeeds, or -1 otherwise.
*/
static inline int
__mutex_fastpath_lock_retval(atomic_t *count)
{
if (unlikely(atomic_dec_return_acquire(count) < 0))
return -1;
return 0;
}
/**
* __mutex_fastpath_unlock - try to promote the count from 0 to 1
* @count: pointer of type atomic_t
* @fail_fn: function to call if the original value was not 0
*
* Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
* In the failure case, this function is allowed to either set the value to
* 1, or to set it to a value lower than 1.
*
* If the implementation sets it to a value of lower than 1, then the
* __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
* to return 0 otherwise.
*/
static inline void
__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
if (unlikely(atomic_inc_return_release(count) <= 0))
fail_fn(count);
}
#define __mutex_slowpath_needs_to_unlock() 1
/**
* __mutex_fastpath_trylock - try to acquire the mutex, without waiting
*
* @count: pointer of type atomic_t
* @fail_fn: fallback function
*
* Change the count from 1 to a value lower than 1, and return 0 (failure)
* if it wasn't 1 originally, or return 1 (success) otherwise. This function
* MUST leave the value lower than 1 even when the "1" assertion wasn't true.
* Additionally, if the value was < 0 originally, this function must not leave
* it to 0 on failure.
*
* If the architecture has no effective trylock variant, it should call the
* <fail_fn> spinlock-based trylock variant unconditionally.
*/
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
if (likely(atomic_read(count) == 1 && atomic_cmpxchg_acquire(count, 1, 0) == 1))
return 1;
return 0;
}
#endif

19
include/asm-generic/mutex-null.h
View file

@ -1,19 +0,0 @@
/*
* include/asm-generic/mutex-null.h
*
* Generic implementation of the mutex fastpath, based on NOP :-)
*
* This is used by the mutex-debugging infrastructure, but it can also
* be used by architectures that (for whatever reason) want to use the
* spinlock based slowpath.
*/
#ifndef _ASM_GENERIC_MUTEX_NULL_H
#define _ASM_GENERIC_MUTEX_NULL_H
#define __mutex_fastpath_lock(count, fail_fn) fail_fn(count)
#define __mutex_fastpath_lock_retval(count) (-1)
#define __mutex_fastpath_unlock(count, fail_fn) fail_fn(count)
#define __mutex_fastpath_trylock(count, fail_fn) fail_fn(count)
#define __mutex_slowpath_needs_to_unlock() 1
#endif

120
include/asm-generic/mutex-xchg.h
View file

@ -1,120 +0,0 @@
/*
* include/asm-generic/mutex-xchg.h
*
* Generic implementation of the mutex fastpath, based on xchg().
*
* NOTE: An xchg based implementation might be less optimal than an atomic
* decrement/increment based implementation. If your architecture
* has a reasonable atomic dec/inc then you should probably use
* asm-generic/mutex-dec.h instead, or you could open-code an
* optimized version in asm/mutex.h.
*/
#ifndef _ASM_GENERIC_MUTEX_XCHG_H
#define _ASM_GENERIC_MUTEX_XCHG_H
/**
* __mutex_fastpath_lock - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
* @fail_fn: function to call if the original value was not 1
*
* Change the count from 1 to a value lower than 1, and call <fail_fn> if it
* wasn't 1 originally. This function MUST leave the value lower than 1
* even when the "1" assertion wasn't true.
*/
static inline void
__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
if (unlikely(atomic_xchg(count, 0) != 1))
/*
* We failed to acquire the lock, so mark it contended
* to ensure that any waiting tasks are woken up by the
* unlock slow path.
*/
if (likely(atomic_xchg_acquire(count, -1) != 1))
fail_fn(count);
}
/**
* __mutex_fastpath_lock_retval - try to take the lock by moving the count
* from 1 to a 0 value
* @count: pointer of type atomic_t
*
* Change the count from 1 to a value lower than 1. This function returns 0
* if the fastpath succeeds, or -1 otherwise.
*/
static inline int
__mutex_fastpath_lock_retval(atomic_t *count)
{
if (unlikely(atomic_xchg_acquire(count, 0) != 1))
if (likely(atomic_xchg(count, -1) != 1))
return -1;
return 0;
}
/**
* __mutex_fastpath_unlock - try to promote the mutex from 0 to 1
* @count: pointer of type atomic_t
* @fail_fn: function to call if the original value was not 0
*
* try to promote the mutex from 0 to 1. if it wasn't 0, call <function>
* In the failure case, this function is allowed to either set the value to
* 1, or to set it to a value lower than one.
* If the implementation sets it to a value of lower than one, the
* __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
* to return 0 otherwise.
*/
static inline void
__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
if (unlikely(atomic_xchg_release(count, 1) != 0))
fail_fn(count);
}
#define __mutex_slowpath_needs_to_unlock() 0
/**
* __mutex_fastpath_trylock - try to acquire the mutex, without waiting
*
* @count: pointer of type atomic_t
* @fail_fn: spinlock based trylock implementation
*
* Change the count from 1 to a value lower than 1, and return 0 (failure)
* if it wasn't 1 originally, or return 1 (success) otherwise. This function
* MUST leave the value lower than 1 even when the "1" assertion wasn't true.
* Additionally, if the value was < 0 originally, this function must not leave
* it to 0 on failure.
*
* If the architecture has no effective trylock variant, it should call the
* <fail_fn> spinlock-based trylock variant unconditionally.
*/
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
int prev;
if (atomic_read(count) != 1)
return 0;
prev = atomic_xchg_acquire(count, 0);
if (unlikely(prev < 0)) {
/*
* The lock was marked contended so we must restore that
* state. If while doing so we get back a prev value of 1
* then we just own it.
*
* [ In the rare case of the mutex going to 1, to 0, to -1
* and then back to 0 in this few-instructions window,
* this has the potential to trigger the slowpath for the
* owner's unlock path needlessly, but that's not a problem
* in practice. ]
*/
prev = atomic_xchg_acquire(count, prev);
if (prev < 0)
prev = 0;
}
return prev;
}
#endif

9
include/asm-generic/mutex.h
View file

@ -1,9 +0,0 @@
#ifndef __ASM_GENERIC_MUTEX_H
#define __ASM_GENERIC_MUTEX_H
/*
* Pull in the generic implementation for the mutex fastpath,
* which is a reasonable default on many architectures.
*/
#include <asm-generic/mutex-dec.h>
#endif /* __ASM_GENERIC_MUTEX_H */

2
include/linux/kvm_host.h
View file

@ -645,6 +645,8 @@ int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
unsigned long len);
int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
void *data, unsigned long len);
int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
void *data, int offset, unsigned long len);
int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
gpa_t gpa, unsigned long len);
int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len);

24
include/linux/mutex-debug.h
View file

@ -1,24 +0,0 @@
#ifndef __LINUX_MUTEX_DEBUG_H
#define __LINUX_MUTEX_DEBUG_H
#include <linux/linkage.h>
#include <linux/lockdep.h>
#include <linux/debug_locks.h>
/*
* Mutexes - debugging helpers:
*/
#define __DEBUG_MUTEX_INITIALIZER(lockname) \
, .magic = &lockname
#define mutex_init(mutex) \
do { \
static struct lock_class_key __key; \
\
__mutex_init((mutex), #mutex, &__key); \
} while (0)
extern void mutex_destroy(struct mutex *lock);
#endif

77
include/linux/mutex.h
View file

@ -18,6 +18,7 @@
#include <linux/atomic.h>
#include <asm/processor.h>
#include <linux/osq_lock.h>
#include <linux/debug_locks.h>
/*
* Simple, straightforward mutexes with strict semantics:
@ -48,16 +49,12 @@
* locks and tasks (and only those tasks)
*/
struct mutex {
/* 1: unlocked, 0: locked, negative: locked, possible waiters */
atomic_t count;
atomic_long_t owner;
spinlock_t wait_lock;
struct list_head wait_list;
#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER)
struct task_struct *owner;
#endif
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
struct optimistic_spin_queue osq; /* Spinner MCS lock */
#endif
struct list_head wait_list;
#ifdef CONFIG_DEBUG_MUTEXES
void *magic;
#endif
@ -66,6 +63,11 @@ struct mutex {
#endif
};
static inline struct task_struct *__mutex_owner(struct mutex *lock)
{
return (struct task_struct *)(atomic_long_read(&lock->owner) & ~0x03);
}
/*
* This is the control structure for tasks blocked on mutex,
* which resides on the blocked task's kernel stack:
@ -79,9 +81,20 @@ struct mutex_waiter {
};
#ifdef CONFIG_DEBUG_MUTEXES
# include <linux/mutex-debug.h>
#define __DEBUG_MUTEX_INITIALIZER(lockname) \
, .magic = &lockname
extern void mutex_destroy(struct mutex *lock);
#else
# define __DEBUG_MUTEX_INITIALIZER(lockname)
static inline void mutex_destroy(struct mutex *lock) {}
#endif
/**
* mutex_init - initialize the mutex
* @mutex: the mutex to be initialized
@ -90,14 +103,12 @@ struct mutex_waiter {
*
* It is not allowed to initialize an already locked mutex.
*/
# define mutex_init(mutex) \
do { \
static struct lock_class_key __key; \
\
__mutex_init((mutex), #mutex, &__key); \
#define mutex_init(mutex) \
do { \
static struct lock_class_key __key; \
\
__mutex_init((mutex), #mutex, &__key); \
} while (0)
static inline void mutex_destroy(struct mutex *lock) {}
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
@ -107,7 +118,7 @@ static inline void mutex_destroy(struct mutex *lock) {}
#endif
#define __MUTEX_INITIALIZER(lockname) \
{ .count = ATOMIC_INIT(1) \
{ .owner = ATOMIC_LONG_INIT(0) \
, .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
, .wait_list = LIST_HEAD_INIT(lockname.wait_list) \
__DEBUG_MUTEX_INITIALIZER(lockname) \
@ -127,7 +138,10 @@ extern void __mutex_init(struct mutex *lock, const char *name,
*/
static inline int mutex_is_locked(struct mutex *lock)
{
return atomic_read(&lock->count) != 1;
/*
* XXX think about spin_is_locked
*/
return __mutex_owner(lock) != NULL;
}
/*
@ -175,4 +189,35 @@ extern void mutex_unlock(struct mutex *lock);
extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
/*
* These values are chosen such that FAIL and SUCCESS match the
* values of the regular mutex_trylock().
*/
enum mutex_trylock_recursive_enum {
MUTEX_TRYLOCK_FAILED = 0,
MUTEX_TRYLOCK_SUCCESS = 1,
MUTEX_TRYLOCK_RECURSIVE,
};
/**
* mutex_trylock_recursive - trylock variant that allows recursive locking
* @lock: mutex to be locked
*
* This function should not be used, _ever_. It is purely for hysterical GEM
* raisins, and once those are gone this will be removed.
*
* Returns:
* MUTEX_TRYLOCK_FAILED - trylock failed,
* 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);
}
#endif /* __LINUX_MUTEX_H */

20
include/linux/sched.h
View file

@ -989,7 +989,7 @@ enum cpu_idle_type {
* already in a wake queue, the wakeup will happen soon and the second
* waker can just skip it.
*
* The WAKE_Q macro declares and initializes the list head.
* The DEFINE_WAKE_Q macro declares and initializes the list head.
* wake_up_q() does NOT reinitialize the list; it's expected to be
* called near the end of a function, where the fact that the queue is
* not used again will be easy to see by inspection.
@ -1009,7 +1009,7 @@ struct wake_q_head {
#define WAKE_Q_TAIL ((struct wake_q_node *) 0x01)
#define WAKE_Q(name) \
#define DEFINE_WAKE_Q(name) \
struct wake_q_head name = { WAKE_Q_TAIL, &name.first }
extern void wake_q_add(struct wake_q_head *head,
@ -2444,6 +2444,10 @@ static inline void calc_load_enter_idle(void) { }
static inline void calc_load_exit_idle(void) { }
#endif /* CONFIG_NO_HZ_COMMON */
#ifndef cpu_relax_yield
#define cpu_relax_yield() cpu_relax()
#endif
/*
* Do not use outside of architecture code which knows its limitations.
*
@ -3508,6 +3512,18 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
#endif /* CONFIG_SMP */
/*
* In order to reduce various lock holder preemption latencies provide an
* interface to see if a vCPU is currently running or not.
*
* This allows us to terminate optimistic spin loops and block, analogous to
* the native optimistic spin heuristic of testing if the lock owner task is
* running or not.
*/
#ifndef vcpu_is_preempted
# define vcpu_is_preempted(cpu) false
#endif
extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
extern long sched_getaffinity(pid_t pid, struct cpumask *mask);

2
include/linux/ww_mutex.h
View file

@ -120,7 +120,7 @@ static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
struct ww_class *ww_class)
{
ctx->task = current;
ctx->stamp = atomic_long_inc_return(&ww_class->stamp);
ctx->stamp = atomic_long_inc_return_relaxed(&ww_class->stamp);
ctx->acquired = 0;
#ifdef CONFIG_DEBUG_MUTEXES
ctx->ww_class = ww_class;

4
ipc/mqueue.c
View file

@ -967,7 +967,7 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
struct timespec ts;
struct posix_msg_tree_node *new_leaf = NULL;
int ret = 0;
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
if (u_abs_timeout) {
int res = prepare_timeout(u_abs_timeout, &expires, &ts);
@ -1151,7 +1151,7 @@ SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
msg_ptr = wait.msg;
}
} else {
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
msg_ptr = msg_get(info);

8
ipc/msg.c
View file

@ -235,7 +235,7 @@ static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
{
struct msg_msg *msg, *t;
struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
expunge_all(msq, -EIDRM, &wake_q);
ss_wakeup(msq, &wake_q, true);
@ -397,7 +397,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
goto out_up;
case IPC_SET:
{
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
!capable(CAP_SYS_RESOURCE)) {
@ -634,7 +634,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
struct msg_msg *msg;
int err;
struct ipc_namespace *ns;
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
ns = current->nsproxy->ipc_ns;
@ -850,7 +850,7 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgfl
struct msg_queue *msq;
struct ipc_namespace *ns;
struct msg_msg *msg, *copy = NULL;
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
ns = current->nsproxy->ipc_ns;

2
kernel/Kconfig.locks
View file

@ -225,7 +225,7 @@ config ARCH_SUPPORTS_ATOMIC_RMW
config MUTEX_SPIN_ON_OWNER
def_bool y
depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW
depends on SMP && ARCH_SUPPORTS_ATOMIC_RMW
config RWSEM_SPIN_ON_OWNER
def_bool y

8
kernel/futex.c
View file

@ -1298,7 +1298,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this,
struct task_struct *new_owner;
struct futex_pi_state *pi_state = this->pi_state;
u32 uninitialized_var(curval), newval;
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
bool deboost;
int ret = 0;
@ -1415,7 +1415,7 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
struct futex_q *this, *next;
union futex_key key = FUTEX_KEY_INIT;
int ret;
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
if (!bitset)
return -EINVAL;
@ -1469,7 +1469,7 @@ futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
struct futex_hash_bucket *hb1, *hb2;
struct futex_q *this, *next;
int ret, op_ret;
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
retry:
ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, VERIFY_READ);
@ -1708,7 +1708,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
struct futex_pi_state *pi_state = NULL;
struct futex_hash_bucket *hb1, *hb2;
struct futex_q *this, *next;
WAKE_Q(wake_q);
DEFINE_WAKE_Q(wake_q);
if (requeue_pi) {
/*

10
kernel/locking/lockdep.c
View file

@ -840,9 +840,9 @@ static struct lock_list *alloc_list_entry(void)
/*
* Add a new dependency to the head of the list:
*/
static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
struct list_head *head, unsigned long ip,
int distance, struct stack_trace *trace)
static int add_lock_to_list(struct lock_class *this, struct list_head *head,
unsigned long ip, int distance,
struct stack_trace *trace)
{
struct lock_list *entry;
/*
@ -1868,14 +1868,14 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
* Ok, all validations passed, add the new lock
* to the previous lock's dependency list:
*/
ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
ret = add_lock_to_list(hlock_class(next),
&hlock_class(prev)->locks_after,
next->acquire_ip, distance, &trace);
if (!ret)
return 0;
ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
ret = add_lock_to_list(hlock_class(prev),
&hlock_class(next)->locks_before,
next->acquire_ip, distance, &trace);
if (!ret)

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