From: Ingo Molnar <mingo@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@us.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [GIT PULL] locking changes for v4.10
Date: Mon, 12 Dec 2016 09:17:11 +0100 [thread overview]
Message-ID: <20161212081711.GA10448@gmail.com> (raw)
Linus,
Please pull the latest locking-core-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-core-for-linus
# HEAD: 11f254dbb3a2e3f0d8552d0dd37f4faa432b6b16 x86/paravirt: Fix bool return type for PVOP_CALL()
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.
Thanks,
Ingo
------------------>
Christian Borntraeger (7):
locking/core: Introduce cpu_relax_yield()
locking/core, stop_machine: Yield the CPU during stop machine()
locking/core, s390: Make cpu_relax() a barrier again
locking/core: Remove cpu_relax_lowlatency() users
locking/core, arch: Remove cpu_relax_lowlatency()
locking/core: Provide common cpu_relax_yield() definition
locking/spinlocks, s390: Implement vcpu_is_preempted(cpu)
Ingo Molnar (2):
locking/drm: Fix i915_gem_shrinker_lock() locking
locking/mutex: Don't mark mutex_trylock_recursive() as deprecated, temporarily
Juergen Gross (1):
x86/xen: Support the vCPU preemption check
Pan Xinhui (9):
sched/core: Introduce the vcpu_is_preempted(cpu) interface
locking/core, powerpc: Implement vcpu_is_preempted(cpu)
locking/core, x86/paravirt: Implement vcpu_is_preempted(cpu) for KVM and Xen guests
kvm: Introduce kvm_write_guest_offset_cached()
x86/kvm: Support the vCPU preemption check
x86/kvm: Support the vCPU preemption check
Documentation/virtual/kvm: Support the vCPU preemption check
locking/osq: Break out of spin-wait busy waiting loop for a preempted vCPU in osq_lock()
locking/mutex: Break out of expensive busy-loop on {mutex,rwsem}_spin_on_owner() when owner vCPU is preempted
Peter Zijlstra (11):
locking/drm: Kill mutex trickery
locking/mutex: Rework mutex::owner
locking/mutex: Kill arch specific code
locking/mutex: Allow MUTEX_SPIN_ON_OWNER when DEBUG_MUTEXES
locking/mutex: Add lock handoff to avoid starvation
locking/mutex: Restructure wait loop
locking/mutex, drm: Introduce mutex_trylock_recursive()
x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted()
locking/ww_mutex: Use relaxed atomics
x86/paravirt: Fix native_patch()
x86/paravirt: Fix bool return type for PVOP_CALL()
Tahsin Erdogan (1):
locking/lockdep: Remove unused parameter from the add_lock_to_list() function
Thomas Gleixner (2):
locking/rtmutex: Get rid of RT_MUTEX_OWNER_MASKALL
locking/rtmutex: Explain locking rules for rt_mutex_proxy_unlock()/init_proxy_locked()
Waiman Long (3):
locking/mutex: Simplify some ww_mutex code in __mutex_lock_common()
locking/mutex: Enable optimistic spinning of woken waiter
sched/wake_q: Rename WAKE_Q to DEFINE_WAKE_Q
Documentation/virtual/kvm/msr.txt | 9 +-
arch/alpha/include/asm/mutex.h | 9 -
arch/alpha/include/asm/processor.h | 1 -
arch/arc/include/asm/mutex.h | 18 -
arch/arc/include/asm/processor.h | 3 -
arch/arm/include/asm/mutex.h | 21 --
arch/arm/include/asm/processor.h | 2 -
arch/arm64/include/asm/Kbuild | 1 -
arch/arm64/include/asm/processor.h | 2 -
arch/avr32/include/asm/mutex.h | 9 -
arch/avr32/include/asm/processor.h | 1 -
arch/blackfin/include/asm/Kbuild | 1 -
arch/blackfin/include/asm/processor.h | 1 -
arch/c6x/include/asm/mutex.h | 6 -
arch/c6x/include/asm/processor.h | 1 -
arch/cris/include/asm/mutex.h | 9 -
arch/cris/include/asm/processor.h | 1 -
arch/frv/include/asm/mutex.h | 9 -
arch/frv/include/asm/processor.h | 1 -
arch/h8300/include/asm/mutex.h | 9 -
arch/h8300/include/asm/processor.h | 1 -
arch/hexagon/include/asm/mutex.h | 8 -
arch/hexagon/include/asm/processor.h | 1 -
arch/ia64/include/asm/mutex.h | 90 -----
arch/ia64/include/asm/processor.h | 1 -
arch/m32r/include/asm/mutex.h | 9 -
arch/m32r/include/asm/processor.h | 1 -
arch/m68k/include/asm/Kbuild | 1 -
arch/m68k/include/asm/processor.h | 1 -
arch/metag/include/asm/Kbuild | 1 -
arch/metag/include/asm/processor.h | 1 -
arch/microblaze/include/asm/mutex.h | 1 -
arch/microblaze/include/asm/processor.h | 1 -
arch/mips/include/asm/Kbuild | 1 -
arch/mips/include/asm/processor.h | 1 -
arch/mn10300/include/asm/mutex.h | 16 -
arch/mn10300/include/asm/processor.h | 1 -
arch/nios2/include/asm/mutex.h | 1 -
arch/nios2/include/asm/processor.h | 1 -
arch/openrisc/include/asm/mutex.h | 27 --
arch/openrisc/include/asm/processor.h | 1 -
arch/parisc/include/asm/Kbuild | 1 -
arch/parisc/include/asm/processor.h | 1 -
arch/powerpc/include/asm/mutex.h | 132 -------
arch/powerpc/include/asm/processor.h | 2 -
arch/powerpc/include/asm/spinlock.h | 8 +
arch/s390/include/asm/mutex.h | 9 -
arch/s390/include/asm/processor.h | 5 +-
arch/s390/include/asm/spinlock.h | 8 +
arch/s390/kernel/processor.c | 4 +-
arch/s390/kernel/smp.c | 9 +-
arch/s390/lib/spinlock.c | 25 +-
arch/score/include/asm/mutex.h | 6 -
arch/score/include/asm/processor.h | 1 -
arch/sh/include/asm/mutex-llsc.h | 109 ------
arch/sh/include/asm/mutex.h | 12 -
arch/sh/include/asm/processor.h | 1 -
arch/sparc/include/asm/Kbuild | 1 -
arch/sparc/include/asm/processor_32.h | 1 -
arch/sparc/include/asm/processor_64.h | 1 -
arch/tile/include/asm/Kbuild | 1 -
arch/tile/include/asm/processor.h | 2 -
arch/um/include/asm/Kbuild | 1 -
arch/unicore32/include/asm/mutex.h | 20 --
arch/unicore32/include/asm/processor.h | 1 -
arch/x86/include/asm/mutex.h | 5 -
arch/x86/include/asm/mutex_32.h | 110 ------
arch/x86/include/asm/mutex_64.h | 127 -------
arch/x86/include/asm/paravirt.h | 5 +
arch/x86/include/asm/paravirt_types.h | 16 +-
arch/x86/include/asm/processor.h | 2 -
arch/x86/include/asm/qspinlock.h | 6 +
arch/x86/include/uapi/asm/kvm_para.h | 4 +-
arch/x86/kernel/kvm.c | 13 +
arch/x86/kernel/paravirt-spinlocks.c | 14 +-
arch/x86/kernel/paravirt_patch_32.c | 12 +
arch/x86/kernel/paravirt_patch_64.c | 12 +
arch/x86/kvm/x86.c | 16 +
arch/x86/um/asm/processor.h | 1 -
arch/x86/xen/spinlock.c | 2 +
arch/xtensa/include/asm/mutex.h | 9 -
arch/xtensa/include/asm/processor.h | 1 -
drivers/gpu/drm/i915/i915_gem_request.c | 2 +-
drivers/gpu/drm/i915/i915_gem_shrinker.c | 30 +-
drivers/gpu/drm/msm/msm_gem_shrinker.c | 27 +-
drivers/vhost/net.c | 4 +-
include/asm-generic/mutex-dec.h | 88 -----
include/asm-generic/mutex-null.h | 19 -
include/asm-generic/mutex-xchg.h | 120 -------
include/asm-generic/mutex.h | 9 -
include/linux/kvm_host.h | 2 +
include/linux/mutex-debug.h | 24 --
include/linux/mutex.h | 77 +++-
include/linux/sched.h | 20 +-
include/linux/ww_mutex.h | 2 +-
ipc/mqueue.c | 4 +-
ipc/msg.c | 8 +-
kernel/Kconfig.locks | 2 +-
kernel/futex.c | 8 +-
kernel/locking/lockdep.c | 10 +-
kernel/locking/mcs_spinlock.h | 4 +-
kernel/locking/mutex-debug.c | 13 -
kernel/locking/mutex-debug.h | 10 -
kernel/locking/mutex.c | 588 ++++++++++++++++++-------------
kernel/locking/mutex.h | 26 --
kernel/locking/osq_lock.c | 15 +-
kernel/locking/qrwlock.c | 6 +-
kernel/locking/rtmutex.c | 18 +-
kernel/locking/rtmutex_common.h | 3 +-
kernel/locking/rwsem-xadd.c | 28 +-
kernel/sched/core.c | 2 +-
kernel/stop_machine.c | 2 +-
lib/lockref.c | 2 +-
scripts/checkpatch.pl | 6 +
virt/kvm/kvm_main.c | 20 +-
115 files changed, 673 insertions(+), 1522 deletions(-)
delete mode 100644 arch/alpha/include/asm/mutex.h
delete mode 100644 arch/arc/include/asm/mutex.h
delete mode 100644 arch/arm/include/asm/mutex.h
delete mode 100644 arch/avr32/include/asm/mutex.h
delete mode 100644 arch/c6x/include/asm/mutex.h
delete mode 100644 arch/cris/include/asm/mutex.h
delete mode 100644 arch/frv/include/asm/mutex.h
delete mode 100644 arch/h8300/include/asm/mutex.h
delete mode 100644 arch/hexagon/include/asm/mutex.h
delete mode 100644 arch/ia64/include/asm/mutex.h
delete mode 100644 arch/m32r/include/asm/mutex.h
delete mode 100644 arch/microblaze/include/asm/mutex.h
delete mode 100644 arch/mn10300/include/asm/mutex.h
delete mode 100644 arch/nios2/include/asm/mutex.h
delete mode 100644 arch/openrisc/include/asm/mutex.h
delete mode 100644 arch/powerpc/include/asm/mutex.h
delete mode 100644 arch/s390/include/asm/mutex.h
delete mode 100644 arch/score/include/asm/mutex.h
delete mode 100644 arch/sh/include/asm/mutex-llsc.h
delete mode 100644 arch/sh/include/asm/mutex.h
delete mode 100644 arch/unicore32/include/asm/mutex.h
delete mode 100644 arch/x86/include/asm/mutex.h
delete mode 100644 arch/x86/include/asm/mutex_32.h
delete mode 100644 arch/x86/include/asm/mutex_64.h
delete mode 100644 arch/xtensa/include/asm/mutex.h
delete mode 100644 include/asm-generic/mutex-dec.h
delete mode 100644 include/asm-generic/mutex-null.h
delete mode 100644 include/asm-generic/mutex-xchg.h
delete mode 100644 include/asm-generic/mutex.h
delete mode 100644 include/linux/mutex-debug.h
diff --git a/Documentation/virtual/kvm/msr.txt b/Documentation/virtual/kvm/msr.txt
index 2a71c8f29f68..0a9ea515512a 100644
--- a/Documentation/virtual/kvm/msr.txt
+++ b/Documentation/virtual/kvm/msr.txt
@@ -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
diff --git a/arch/alpha/include/asm/mutex.h b/arch/alpha/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/alpha/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/alpha/include/asm/processor.h b/arch/alpha/include/asm/processor.h
index 43a7559c448b..2fec2dee3020 100644
--- a/arch/alpha/include/asm/processor.h
+++ b/arch/alpha/include/asm/processor.h
@@ -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
diff --git a/arch/arc/include/asm/mutex.h b/arch/arc/include/asm/mutex.h
deleted file mode 100644
index a2f88ff9f506..000000000000
--- a/arch/arc/include/asm/mutex.h
+++ /dev/null
@@ -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
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 16b630fbeb6a..6e1242da0159 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -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)
diff --git a/arch/arm/include/asm/mutex.h b/arch/arm/include/asm/mutex.h
deleted file mode 100644
index 87c044910fe0..000000000000
--- a/arch/arm/include/asm/mutex.h
+++ /dev/null
@@ -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 */
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 8a1e8e995dae..c3d5fc124a05 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -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)
diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild
index 44e1d7f10add..b4ab238a59ec 100644
--- a/arch/arm64/include/asm/Kbuild
+++ b/arch/arm64/include/asm/Kbuild
@@ -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
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 60e34824e18c..747c65a616ed 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -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);
diff --git a/arch/avr32/include/asm/mutex.h b/arch/avr32/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/avr32/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/avr32/include/asm/processor.h b/arch/avr32/include/asm/processor.h
index 941593c7d9f3..972adcc1e8f4 100644
--- a/arch/avr32/include/asm/processor.h
+++ b/arch/avr32/include/asm/processor.h
@@ -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 {
diff --git a/arch/blackfin/include/asm/Kbuild b/arch/blackfin/include/asm/Kbuild
index 91d49c0a3118..2fb67b59d188 100644
--- a/arch/blackfin/include/asm/Kbuild
+++ b/arch/blackfin/include/asm/Kbuild
@@ -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
diff --git a/arch/blackfin/include/asm/processor.h b/arch/blackfin/include/asm/processor.h
index 0c265aba94ad..85d4af97c986 100644
--- a/arch/blackfin/include/asm/processor.h
+++ b/arch/blackfin/include/asm/processor.h
@@ -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)
diff --git a/arch/c6x/include/asm/mutex.h b/arch/c6x/include/asm/mutex.h
deleted file mode 100644
index 7a7248e0462d..000000000000
--- a/arch/c6x/include/asm/mutex.h
+++ /dev/null
@@ -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 */
diff --git a/arch/c6x/include/asm/processor.h b/arch/c6x/include/asm/processor.h
index f2ef31be2f8b..b9eb3da7f278 100644
--- a/arch/c6x/include/asm/processor.h
+++ b/arch/c6x/include/asm/processor.h
@@ -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;
diff --git a/arch/cris/include/asm/mutex.h b/arch/cris/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/cris/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/cris/include/asm/processor.h b/arch/cris/include/asm/processor.h
index 862126b58116..15b815df29c1 100644
--- a/arch/cris/include/asm/processor.h
+++ b/arch/cris/include/asm/processor.h
@@ -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);
diff --git a/arch/frv/include/asm/mutex.h b/arch/frv/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/frv/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/frv/include/asm/processor.h b/arch/frv/include/asm/processor.h
index 73f0a79ad8e6..ddaeb9cc9143 100644
--- a/arch/frv/include/asm/processor.h
+++ b/arch/frv/include/asm/processor.h
@@ -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
diff --git a/arch/h8300/include/asm/mutex.h b/arch/h8300/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/h8300/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/h8300/include/asm/processor.h b/arch/h8300/include/asm/processor.h
index 111df7397ac7..65132d7ae9e5 100644
--- a/arch/h8300/include/asm/processor.h
+++ b/arch/h8300/include/asm/processor.h
@@ -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(); \
diff --git a/arch/hexagon/include/asm/mutex.h b/arch/hexagon/include/asm/mutex.h
deleted file mode 100644
index 58b52de1bc22..000000000000
--- a/arch/hexagon/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/hexagon/include/asm/processor.h b/arch/hexagon/include/asm/processor.h
index d8501137c8d0..45a825402f63 100644
--- a/arch/hexagon/include/asm/processor.h
+++ b/arch/hexagon/include/asm/processor.h
@@ -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
diff --git a/arch/ia64/include/asm/mutex.h b/arch/ia64/include/asm/mutex.h
deleted file mode 100644
index 28cb819e0ff9..000000000000
--- a/arch/ia64/include/asm/mutex.h
+++ /dev/null
@@ -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
diff --git a/arch/ia64/include/asm/processor.h b/arch/ia64/include/asm/processor.h
index ce53c50d0ba4..03911a336406 100644
--- a/arch/ia64/include/asm/processor.h
+++ b/arch/ia64/include/asm/processor.h
@@ -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)
diff --git a/arch/m32r/include/asm/mutex.h b/arch/m32r/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/m32r/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/m32r/include/asm/processor.h b/arch/m32r/include/asm/processor.h
index 9f8fd9bef70f..5767367550c6 100644
--- a/arch/m32r/include/asm/processor.h
+++ b/arch/m32r/include/asm/processor.h
@@ -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 */
diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild
index eb85bd9c6180..1f2e5d31cb24 100644
--- a/arch/m68k/include/asm/Kbuild
+++ b/arch/m68k/include/asm/Kbuild
@@ -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
diff --git a/arch/m68k/include/asm/processor.h b/arch/m68k/include/asm/processor.h
index c84a2183b3f0..f5f790c31bf8 100644
--- a/arch/m68k/include/asm/processor.h
+++ b/arch/m68k/include/asm/processor.h
@@ -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
diff --git a/arch/metag/include/asm/Kbuild b/arch/metag/include/asm/Kbuild
index 29acb89daaaa..167150c701d1 100644
--- a/arch/metag/include/asm/Kbuild
+++ b/arch/metag/include/asm/Kbuild
@@ -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
diff --git a/arch/metag/include/asm/processor.h b/arch/metag/include/asm/processor.h
index a0333ebcac35..ec6a49076980 100644
--- a/arch/metag/include/asm/processor.h
+++ b/arch/metag/include/asm/processor.h
@@ -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);
diff --git a/arch/microblaze/include/asm/mutex.h b/arch/microblaze/include/asm/mutex.h
deleted file mode 100644
index ff6101aa2c71..000000000000
--- a/arch/microblaze/include/asm/mutex.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/microblaze/include/asm/processor.h b/arch/microblaze/include/asm/processor.h
index c38d0dd91134..37ef196e4519 100644
--- a/arch/microblaze/include/asm/processor.h
+++ b/arch/microblaze/include/asm/processor.h
@@ -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)
diff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild
index 9740066cc631..3269b742a75e 100644
--- a/arch/mips/include/asm/Kbuild
+++ b/arch/mips/include/asm/Kbuild
@@ -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
diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index 0d36c87acbe2..95b8c471f572 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -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)
diff --git a/arch/mn10300/include/asm/mutex.h b/arch/mn10300/include/asm/mutex.h
deleted file mode 100644
index 84f5490c6fb4..000000000000
--- a/arch/mn10300/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/mn10300/include/asm/processor.h b/arch/mn10300/include/asm/processor.h
index b10ba121c849..18e17abf7664 100644
--- a/arch/mn10300/include/asm/processor.h
+++ b/arch/mn10300/include/asm/processor.h
@@ -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).
diff --git a/arch/nios2/include/asm/mutex.h b/arch/nios2/include/asm/mutex.h
deleted file mode 100644
index ff6101aa2c71..000000000000
--- a/arch/nios2/include/asm/mutex.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm-generic/mutex-dec.h>
diff --git a/arch/nios2/include/asm/processor.h b/arch/nios2/include/asm/processor.h
index 1c953f0cadbf..3bbbc3d798e5 100644
--- a/arch/nios2/include/asm/processor.h
+++ b/arch/nios2/include/asm/processor.h
@@ -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__ */
diff --git a/arch/openrisc/include/asm/mutex.h b/arch/openrisc/include/asm/mutex.h
deleted file mode 100644
index b85a0cfa9fc9..000000000000
--- a/arch/openrisc/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/openrisc/include/asm/processor.h b/arch/openrisc/include/asm/processor.h
index 70334c9f7d24..a908e6c30a00 100644
--- a/arch/openrisc/include/asm/processor.h
+++ b/arch/openrisc/include/asm/processor.h
@@ -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 */
diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild
index f9b3a81aefcd..91f53c07f410 100644
--- a/arch/parisc/include/asm/Kbuild
+++ b/arch/parisc/include/asm/Kbuild
@@ -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
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index 2e674e13e005..ca40741378be 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -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
diff --git a/arch/powerpc/include/asm/mutex.h b/arch/powerpc/include/asm/mutex.h
deleted file mode 100644
index 078155fa1189..000000000000
--- a/arch/powerpc/include/asm/mutex.h
+++ /dev/null
@@ -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
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index c07c31b0e89e..dac83fcb9445 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -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);
diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
index fa37fe93bc02..8c1b913de6d7 100644
--- a/arch/powerpc/include/asm/spinlock.h
+++ b/arch/powerpc/include/asm/spinlock.h
@@ -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;
diff --git a/arch/s390/include/asm/mutex.h b/arch/s390/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/s390/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 602af692efdc..9d3a21aedc97 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -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
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index 7e9e09f600fa..7ecd8902a5c3 100644
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -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.
diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c
index 81d0808085e6..9e60ef144d03 100644
--- a/arch/s390/kernel/processor.c
+++ b/arch/s390/kernel/processor.c
@@ -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.
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 35531fe1c5ea..b988ed1d75ad 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -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)
{
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index e5f50a7d2f4e..e48a48ec24bc 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -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);
}
diff --git a/arch/score/include/asm/mutex.h b/arch/score/include/asm/mutex.h
deleted file mode 100644
index 10d48fe4db97..000000000000
--- a/arch/score/include/asm/mutex.h
+++ /dev/null
@@ -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 */
diff --git a/arch/score/include/asm/processor.h b/arch/score/include/asm/processor.h
index 851f441991d2..d9a922d8711b 100644
--- a/arch/score/include/asm/processor.h
+++ b/arch/score/include/asm/processor.h
@@ -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)
/*
diff --git a/arch/sh/include/asm/mutex-llsc.h b/arch/sh/include/asm/mutex-llsc.h
deleted file mode 100644
index dad29b687bd3..000000000000
--- a/arch/sh/include/asm/mutex-llsc.h
+++ /dev/null
@@ -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 */
diff --git a/arch/sh/include/asm/mutex.h b/arch/sh/include/asm/mutex.h
deleted file mode 100644
index d8e37716a4a0..000000000000
--- a/arch/sh/include/asm/mutex.h
+++ /dev/null
@@ -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
diff --git a/arch/sh/include/asm/processor.h b/arch/sh/include/asm/processor.h
index f9a09942a32d..5addd69f70ef 100644
--- a/arch/sh/include/asm/processor.h
+++ b/arch/sh/include/asm/processor.h
@@ -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 *);
diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild
index cfc918067f80..0569bfac4afb 100644
--- a/arch/sparc/include/asm/Kbuild
+++ b/arch/sparc/include/asm/Kbuild
@@ -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
diff --git a/arch/sparc/include/asm/processor_32.h b/arch/sparc/include/asm/processor_32.h
index 812fd08f3e62..365d4cb267b4 100644
--- a/arch/sparc/include/asm/processor_32.h
+++ b/arch/sparc/include/asm/processor_32.h
@@ -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);
diff --git a/arch/sparc/include/asm/processor_64.h b/arch/sparc/include/asm/processor_64.h
index ce2595c89471..6448cfc8292f 100644
--- a/arch/sparc/include/asm/processor_64.h
+++ b/arch/sparc/include/asm/processor_64.h
@@ -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
diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild
index ba35c41c71ff..2d1f5638974c 100644
--- a/arch/tile/include/asm/Kbuild
+++ b/arch/tile/include/asm/Kbuild
@@ -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
diff --git a/arch/tile/include/asm/processor.h b/arch/tile/include/asm/processor.h
index 0684e88aacd8..0bc9968b97a1 100644
--- a/arch/tile/include/asm/processor.h
+++ b/arch/tile/include/asm/processor.h
@@ -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;
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index 904f3ebf4220..052f7f6d0551 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -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
diff --git a/arch/unicore32/include/asm/mutex.h b/arch/unicore32/include/asm/mutex.h
deleted file mode 100644
index fab7d0e8adf6..000000000000
--- a/arch/unicore32/include/asm/mutex.h
+++ /dev/null
@@ -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
diff --git a/arch/unicore32/include/asm/processor.h b/arch/unicore32/include/asm/processor.h
index 8d21b7adf26b..4eaa42167667 100644
--- a/arch/unicore32/include/asm/processor.h
+++ b/arch/unicore32/include/asm/processor.h
@@ -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)
diff --git a/arch/x86/include/asm/mutex.h b/arch/x86/include/asm/mutex.h
deleted file mode 100644
index 7d3a48275394..000000000000
--- a/arch/x86/include/asm/mutex.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#ifdef CONFIG_X86_32
-# include <asm/mutex_32.h>
-#else
-# include <asm/mutex_64.h>
-#endif
diff --git a/arch/x86/include/asm/mutex_32.h b/arch/x86/include/asm/mutex_32.h
deleted file mode 100644
index e9355a84fc67..000000000000
--- a/arch/x86/include/asm/mutex_32.h
+++ /dev/null
@@ -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 */
diff --git a/arch/x86/include/asm/mutex_64.h b/arch/x86/include/asm/mutex_64.h
deleted file mode 100644
index d9850758464e..000000000000
--- a/arch/x86/include/asm/mutex_64.h
+++ /dev/null
@@ -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 */
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index ce932812f142..6108b1fada2b 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -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
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 0f400c0e4979..3f2bc0f0d3e8 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -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; \
})
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 984a7bf17f6a..c84605bb2a15 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -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)
{
diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h
index eaba08076030..c343ab52579f 100644
--- a/arch/x86/include/asm/qspinlock.h
+++ b/arch/x86/include/asm/qspinlock.h
@@ -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)
{
diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 94dc8ca434e0..1421a6585126 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -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
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index edbbfc854e39..52e90d6054fb 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -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)
diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 2c55a003b793..6d4bf812af45 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -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);
diff --git a/arch/x86/kernel/paravirt_patch_32.c b/arch/x86/kernel/paravirt_patch_32.c
index 920c6ae08592..33cdec221f3d 100644
--- a/arch/x86/kernel/paravirt_patch_32.c
+++ b/arch/x86/kernel/paravirt_patch_32.c
@@ -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;
diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
index bb3840cedb4f..b0fceff502b3 100644
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -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;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 04c5d96b1d67..59c2d6f1b131 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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();
diff --git a/arch/x86/um/asm/processor.h b/arch/x86/um/asm/processor.h
index 233ee09c1ce8..c77db2288982 100644
--- a/arch/x86/um/asm/processor.h
+++ b/arch/x86/um/asm/processor.h
@@ -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)
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 3d6e0064cbfc..e8a9ea7d7a21 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -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);
}
/*
diff --git a/arch/xtensa/include/asm/mutex.h b/arch/xtensa/include/asm/mutex.h
deleted file mode 100644
index 458c1f7fbc18..000000000000
--- a/arch/xtensa/include/asm/mutex.h
+++ /dev/null
@@ -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>
diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h
index b42d68bfe3cf..86ffcd68e496 100644
--- a/arch/xtensa/include/asm/processor.h
+++ b/arch/xtensa/include/asm/processor.h
@@ -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. */
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 8832f8ec1583..383d13416442 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -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;
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 1c237d02f30b..c450076d2f9b 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -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
diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index 192b2d3a79cb..ab1dd020eb04 100644
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -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)
+static bool msm_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
{
- if (!mutex_is_locked(mutex))
+ switch (mutex_trylock_recursive(&dev->struct_mutex)) {
+ case MUTEX_TRYLOCK_FAILED:
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
-}
+ case MUTEX_TRYLOCK_SUCCESS:
+ *unlock = true;
+ return true;
-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;
+ case MUTEX_TRYLOCK_RECURSIVE:
*unlock = false;
- } else {
- *unlock = true;
+ return true;
}
- return true;
+ BUG();
}
-
static unsigned long
msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
{
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 5dc128a8da83..5dc34653274a 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -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();
diff --git a/include/asm-generic/mutex-dec.h b/include/asm-generic/mutex-dec.h
deleted file mode 100644
index c54829d3de37..000000000000
--- a/include/asm-generic/mutex-dec.h
+++ /dev/null
@@ -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
diff --git a/include/asm-generic/mutex-null.h b/include/asm-generic/mutex-null.h
deleted file mode 100644
index 61069ed334e2..000000000000
--- a/include/asm-generic/mutex-null.h
+++ /dev/null
@@ -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
diff --git a/include/asm-generic/mutex-xchg.h b/include/asm-generic/mutex-xchg.h
deleted file mode 100644
index 3269ec4e195f..000000000000
--- a/include/asm-generic/mutex-xchg.h
+++ /dev/null
@@ -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
diff --git a/include/asm-generic/mutex.h b/include/asm-generic/mutex.h
deleted file mode 100644
index fe91ab502793..000000000000
--- a/include/asm-generic/mutex.h
+++ /dev/null
@@ -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 */
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 01c0b9cc3915..6f0023797b33 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -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);
diff --git a/include/linux/mutex-debug.h b/include/linux/mutex-debug.h
deleted file mode 100644
index 4ac8b1977b73..000000000000
--- a/include/linux/mutex-debug.h
+++ /dev/null
@@ -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
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 2cb7531e7d7a..b97870f2debd 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -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 */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index e9c009dc3a4a..8863bdf582d5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -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);
diff --git a/include/linux/ww_mutex.h b/include/linux/ww_mutex.h
index 2bb5deb0012e..7b0066814fa0 100644
--- a/include/linux/ww_mutex.h
+++ b/include/linux/ww_mutex.h
@@ -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;
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 8cbd6e6894d5..7a2d8f0c8ae5 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -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);
diff --git a/ipc/msg.c b/ipc/msg.c
index e12307d0c920..32e9bd837cde 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -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;
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index ebdb0043203a..84d882f3e299 100644
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -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
diff --git a/kernel/futex.c b/kernel/futex.c
index 2c4be467fecd..9246d9f593d1 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -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) {
/*
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 4d7ffc0a0d00..7bd265f6b098 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -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)
diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h
index c835270f0c2f..6a385aabcce7 100644
--- a/kernel/locking/mcs_spinlock.h
+++ b/kernel/locking/mcs_spinlock.h
@@ -28,7 +28,7 @@ struct mcs_spinlock {
#define arch_mcs_spin_lock_contended(l) \
do { \
while (!(smp_load_acquire(l))) \
- cpu_relax_lowlatency(); \
+ cpu_relax(); \
} while (0)
#endif
@@ -108,7 +108,7 @@ void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node)
return;
/* Wait until the next pointer is set */
while (!(next = READ_ONCE(node->next)))
- cpu_relax_lowlatency();
+ cpu_relax();
}
/* Pass lock to next waiter. */
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
index 9c951fade415..9aa713629387 100644
--- a/kernel/locking/mutex-debug.c
+++ b/kernel/locking/mutex-debug.c
@@ -73,21 +73,8 @@ void debug_mutex_unlock(struct mutex *lock)
{
if (likely(debug_locks)) {
DEBUG_LOCKS_WARN_ON(lock->magic != lock);
-
- if (!lock->owner)
- DEBUG_LOCKS_WARN_ON(!lock->owner);
- else
- DEBUG_LOCKS_WARN_ON(lock->owner != current);
-
DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
}
-
- /*
- * __mutex_slowpath_needs_to_unlock() is explicitly 0 for debug
- * mutexes so that we can do it here after we've verified state.
- */
- mutex_clear_owner(lock);
- atomic_set(&lock->count, 1);
}
void debug_mutex_init(struct mutex *lock, const char *name,
diff --git a/kernel/locking/mutex-debug.h b/kernel/locking/mutex-debug.h
index 57a871ae3c81..a459faa48987 100644
--- a/kernel/locking/mutex-debug.h
+++ b/kernel/locking/mutex-debug.h
@@ -27,16 +27,6 @@ extern void debug_mutex_unlock(struct mutex *lock);
extern void debug_mutex_init(struct mutex *lock, const char *name,
struct lock_class_key *key);
-static inline void mutex_set_owner(struct mutex *lock)
-{
- WRITE_ONCE(lock->owner, current);
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
- WRITE_ONCE(lock->owner, NULL);
-}
-
#define spin_lock_mutex(lock, flags) \
do { \
struct mutex *l = container_of(lock, struct mutex, wait_lock); \
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index a70b90db3909..9b349619f431 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -27,41 +27,176 @@
#include <linux/debug_locks.h>
#include <linux/osq_lock.h>
-/*
- * In the DEBUG case we are using the "NULL fastpath" for mutexes,
- * which forces all calls into the slowpath:
- */
#ifdef CONFIG_DEBUG_MUTEXES
# include "mutex-debug.h"
-# include <asm-generic/mutex-null.h>
-/*
- * Must be 0 for the debug case so we do not do the unlock outside of the
- * wait_lock region. debug_mutex_unlock() will do the actual unlock in this
- * case.
- */
-# undef __mutex_slowpath_needs_to_unlock
-# define __mutex_slowpath_needs_to_unlock() 0
#else
# include "mutex.h"
-# include <asm/mutex.h>
#endif
void
__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
{
- atomic_set(&lock->count, 1);
+ atomic_long_set(&lock->owner, 0);
spin_lock_init(&lock->wait_lock);
INIT_LIST_HEAD(&lock->wait_list);
- mutex_clear_owner(lock);
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
osq_lock_init(&lock->osq);
#endif
debug_mutex_init(lock, name, key);
}
-
EXPORT_SYMBOL(__mutex_init);
+/*
+ * @owner: contains: 'struct task_struct *' to the current lock owner,
+ * NULL means not owned. Since task_struct pointers are aligned at
+ * ARCH_MIN_TASKALIGN (which is at least sizeof(void *)), we have low
+ * bits to store extra state.
+ *
+ * Bit0 indicates a non-empty waiter list; unlock must issue a wakeup.
+ * Bit1 indicates unlock needs to hand the lock to the top-waiter
+ */
+#define MUTEX_FLAG_WAITERS 0x01
+#define MUTEX_FLAG_HANDOFF 0x02
+
+#define MUTEX_FLAGS 0x03
+
+static inline struct task_struct *__owner_task(unsigned long owner)
+{
+ return (struct task_struct *)(owner & ~MUTEX_FLAGS);
+}
+
+static inline unsigned long __owner_flags(unsigned long owner)
+{
+ return owner & MUTEX_FLAGS;
+}
+
+/*
+ * Actual trylock that will work on any unlocked state.
+ *
+ * When setting the owner field, we must preserve the low flag bits.
+ *
+ * Be careful with @handoff, only set that in a wait-loop (where you set
+ * HANDOFF) to avoid recursive lock attempts.
+ */
+static inline bool __mutex_trylock(struct mutex *lock, const bool handoff)
+{
+ unsigned long owner, curr = (unsigned long)current;
+
+ owner = atomic_long_read(&lock->owner);
+ for (;;) { /* must loop, can race against a flag */
+ unsigned long old, flags = __owner_flags(owner);
+
+ if (__owner_task(owner)) {
+ if (handoff && unlikely(__owner_task(owner) == current)) {
+ /*
+ * Provide ACQUIRE semantics for the lock-handoff.
+ *
+ * We cannot easily use load-acquire here, since
+ * the actual load is a failed cmpxchg, which
+ * doesn't imply any barriers.
+ *
+ * Also, this is a fairly unlikely scenario, and
+ * this contains the cost.
+ */
+ smp_mb(); /* ACQUIRE */
+ return true;
+ }
+
+ return false;
+ }
+
+ /*
+ * We set the HANDOFF bit, we must make sure it doesn't live
+ * past the point where we acquire it. This would be possible
+ * if we (accidentally) set the bit on an unlocked mutex.
+ */
+ if (handoff)
+ flags &= ~MUTEX_FLAG_HANDOFF;
+
+ old = atomic_long_cmpxchg_acquire(&lock->owner, owner, curr | flags);
+ if (old == owner)
+ return true;
+
+ owner = old;
+ }
+}
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * Lockdep annotations are contained to the slow paths for simplicity.
+ * There is nothing that would stop spreading the lockdep annotations outwards
+ * except more code.
+ */
+
+/*
+ * Optimistic trylock that only works in the uncontended case. Make sure to
+ * follow with a __mutex_trylock() before failing.
+ */
+static __always_inline bool __mutex_trylock_fast(struct mutex *lock)
+{
+ unsigned long curr = (unsigned long)current;
+
+ if (!atomic_long_cmpxchg_acquire(&lock->owner, 0UL, curr))
+ return true;
+
+ return false;
+}
+
+static __always_inline bool __mutex_unlock_fast(struct mutex *lock)
+{
+ unsigned long curr = (unsigned long)current;
+
+ if (atomic_long_cmpxchg_release(&lock->owner, curr, 0UL) == curr)
+ return true;
+
+ return false;
+}
+#endif
+
+static inline void __mutex_set_flag(struct mutex *lock, unsigned long flag)
+{
+ atomic_long_or(flag, &lock->owner);
+}
+
+static inline void __mutex_clear_flag(struct mutex *lock, unsigned long flag)
+{
+ atomic_long_andnot(flag, &lock->owner);
+}
+
+static inline bool __mutex_waiter_is_first(struct mutex *lock, struct mutex_waiter *waiter)
+{
+ return list_first_entry(&lock->wait_list, struct mutex_waiter, list) == waiter;
+}
+
+/*
+ * Give up ownership to a specific task, when @task = NULL, this is equivalent
+ * to a regular unlock. Clears HANDOFF, preserves WAITERS. Provides RELEASE
+ * semantics like a regular unlock, the __mutex_trylock() provides matching
+ * ACQUIRE semantics for the handoff.
+ */
+static void __mutex_handoff(struct mutex *lock, struct task_struct *task)
+{
+ unsigned long owner = atomic_long_read(&lock->owner);
+
+ for (;;) {
+ unsigned long old, new;
+
+#ifdef CONFIG_DEBUG_MUTEXES
+ DEBUG_LOCKS_WARN_ON(__owner_task(owner) != current);
+#endif
+
+ new = (owner & MUTEX_FLAG_WAITERS);
+ new |= (unsigned long)task;
+
+ old = atomic_long_cmpxchg_release(&lock->owner, owner, new);
+ if (old == owner)
+ break;
+
+ owner = old;
+ }
+}
+
#ifndef CONFIG_DEBUG_LOCK_ALLOC
/*
* We split the mutex lock/unlock logic into separate fastpath and
@@ -69,7 +204,7 @@ EXPORT_SYMBOL(__mutex_init);
* We also put the fastpath first in the kernel image, to make sure the
* branch is predicted by the CPU as default-untaken.
*/
-__visible void __sched __mutex_lock_slowpath(atomic_t *lock_count);
+static void __sched __mutex_lock_slowpath(struct mutex *lock);
/**
* mutex_lock - acquire the mutex
@@ -95,14 +230,10 @@ __visible void __sched __mutex_lock_slowpath(atomic_t *lock_count);
void __sched mutex_lock(struct mutex *lock)
{
might_sleep();
- /*
- * The locking fastpath is the 1->0 transition from
- * 'unlocked' into 'locked' state.
- */
- __mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
- mutex_set_owner(lock);
-}
+ if (!__mutex_trylock_fast(lock))
+ __mutex_lock_slowpath(lock);
+}
EXPORT_SYMBOL(mutex_lock);
#endif
@@ -149,9 +280,6 @@ static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
/*
* After acquiring lock with fastpath or when we lost out in contested
* slowpath, set ctx and wake up any waiters so they can recheck.
- *
- * This function is never called when CONFIG_DEBUG_LOCK_ALLOC is set,
- * as the fastpath and opportunistic spinning are disabled in that case.
*/
static __always_inline void
ww_mutex_set_context_fastpath(struct ww_mutex *lock,
@@ -176,7 +304,7 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock,
/*
* Check if lock is contended, if not there is nobody to wake up
*/
- if (likely(atomic_read(&lock->base.count) == 0))
+ if (likely(!(atomic_long_read(&lock->base.owner) & MUTEX_FLAG_WAITERS)))
return;
/*
@@ -227,7 +355,7 @@ bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
bool ret = true;
rcu_read_lock();
- while (lock->owner == owner) {
+ while (__mutex_owner(lock) == owner) {
/*
* Ensure we emit the owner->on_cpu, dereference _after_
* checking lock->owner still matches owner. If that fails,
@@ -236,12 +364,16 @@ bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
*/
barrier();
- if (!owner->on_cpu || need_resched()) {
+ /*
+ * Use vcpu_is_preempted to detect lock holder preemption issue.
+ */
+ if (!owner->on_cpu || need_resched() ||
+ vcpu_is_preempted(task_cpu(owner))) {
ret = false;
break;
}
- cpu_relax_lowlatency();
+ cpu_relax();
}
rcu_read_unlock();
@@ -260,27 +392,25 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
return 0;
rcu_read_lock();
- owner = READ_ONCE(lock->owner);
+ owner = __mutex_owner(lock);
+
+ /*
+ * As lock holder preemption issue, we both skip spinning if task is not
+ * on cpu or its cpu is preempted
+ */
if (owner)
- retval = owner->on_cpu;
+ retval = owner->on_cpu && !vcpu_is_preempted(task_cpu(owner));
rcu_read_unlock();
+
/*
- * if lock->owner is not set, the mutex owner may have just acquired
- * it and not set the owner yet or the mutex has been released.
+ * If lock->owner is not set, the mutex has been released. Return true
+ * such that we'll trylock in the spin path, which is a faster option
+ * than the blocking slow path.
*/
return retval;
}
/*
- * Atomically try to take the lock when it is available
- */
-static inline bool mutex_try_to_acquire(struct mutex *lock)
-{
- return !mutex_is_locked(lock) &&
- (atomic_cmpxchg_acquire(&lock->count, 1, 0) == 1);
-}
-
-/*
* Optimistic spinning.
*
* We try to spin for acquisition when we find that the lock owner
@@ -288,13 +418,6 @@ static inline bool mutex_try_to_acquire(struct mutex *lock)
* 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
- * track it non-atomically.
- *
- * We can't do this for DEBUG_MUTEXES because that relies on wait_lock
- * to serialize everything.
- *
* The mutex spinners are queued up using MCS lock so that only one
* spinner can compete for the mutex. However, if mutex spinning isn't
* going to happen, there is no point in going through the lock/unlock
@@ -302,24 +425,39 @@ static inline bool mutex_try_to_acquire(struct mutex *lock)
*
* Returns true when the lock was taken, otherwise false, indicating
* that we need to jump to the slowpath and sleep.
+ *
+ * The waiter flag is set to true if the spinner is a waiter in the wait
+ * queue. The waiter-spinner will spin on the lock directly and concurrently
+ * with the spinner at the head of the OSQ, if present, until the owner is
+ * changed to itself.
*/
static bool mutex_optimistic_spin(struct mutex *lock,
- struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
+ struct ww_acquire_ctx *ww_ctx,
+ const bool use_ww_ctx, const bool waiter)
{
struct task_struct *task = current;
- if (!mutex_can_spin_on_owner(lock))
- goto done;
+ if (!waiter) {
+ /*
+ * The purpose of the mutex_can_spin_on_owner() function is
+ * to eliminate the overhead of osq_lock() and osq_unlock()
+ * in case spinning isn't possible. As a waiter-spinner
+ * is not going to take OSQ lock anyway, there is no need
+ * to call mutex_can_spin_on_owner().
+ */
+ if (!mutex_can_spin_on_owner(lock))
+ goto fail;
- /*
- * In order to avoid a stampede of mutex spinners trying to
- * acquire the mutex all at once, the spinners need to take a
- * MCS (queued) lock first before spinning on the owner field.
- */
- if (!osq_lock(&lock->osq))
- goto done;
+ /*
+ * In order to avoid a stampede of mutex spinners trying to
+ * acquire the mutex all at once, the spinners need to take a
+ * MCS (queued) lock first before spinning on the owner field.
+ */
+ if (!osq_lock(&lock->osq))
+ goto fail;
+ }
- while (true) {
+ for (;;) {
struct task_struct *owner;
if (use_ww_ctx && ww_ctx->acquired > 0) {
@@ -335,40 +473,26 @@ static bool mutex_optimistic_spin(struct mutex *lock,
* performed the optimistic spinning cannot be done.
*/
if (READ_ONCE(ww->ctx))
- break;
+ goto fail_unlock;
}
/*
* If there's an owner, wait for it to either
* release the lock or go to sleep.
*/
- owner = READ_ONCE(lock->owner);
- if (owner && !mutex_spin_on_owner(lock, owner))
- break;
-
- /* Try to acquire the mutex if it is unlocked. */
- if (mutex_try_to_acquire(lock)) {
- lock_acquired(&lock->dep_map, ip);
-
- if (use_ww_ctx) {
- struct ww_mutex *ww;
- ww = container_of(lock, struct ww_mutex, base);
-
- ww_mutex_set_context_fastpath(ww, ww_ctx);
+ owner = __mutex_owner(lock);
+ if (owner) {
+ if (waiter && owner == task) {
+ smp_mb(); /* ACQUIRE */
+ break;
}
- mutex_set_owner(lock);
- osq_unlock(&lock->osq);
- return true;
+ if (!mutex_spin_on_owner(lock, owner))
+ goto fail_unlock;
}
- /*
- * When there's no owner, we might have preempted between the
- * owner acquiring the lock and setting the owner field. If
- * we're an RT task that will live-lock because we won't let
- * the owner complete.
- */
- if (!owner && (need_resched() || rt_task(task)))
+ /* Try to acquire the mutex if it is unlocked. */
+ if (__mutex_trylock(lock, waiter))
break;
/*
@@ -377,11 +501,20 @@ static bool mutex_optimistic_spin(struct mutex *lock,
* memory barriers as we'll eventually observe the right
* values at the cost of a few extra spins.
*/
- cpu_relax_lowlatency();
+ cpu_relax();
}
- osq_unlock(&lock->osq);
-done:
+ if (!waiter)
+ osq_unlock(&lock->osq);
+
+ return true;
+
+
+fail_unlock:
+ if (!waiter)
+ osq_unlock(&lock->osq);
+
+fail:
/*
* If we fell out of the spin path because of need_resched(),
* reschedule now, before we try-lock the mutex. This avoids getting
@@ -400,14 +533,14 @@ static bool mutex_optimistic_spin(struct mutex *lock,
}
#else
static bool mutex_optimistic_spin(struct mutex *lock,
- struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
+ struct ww_acquire_ctx *ww_ctx,
+ const bool use_ww_ctx, const bool waiter)
{
return false;
}
#endif
-__visible __used noinline
-void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
+static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigned long ip);
/**
* mutex_unlock - release the mutex
@@ -422,21 +555,12 @@ void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
*/
void __sched mutex_unlock(struct mutex *lock)
{
- /*
- * The unlocking fastpath is the 0->1 transition from 'locked'
- * into 'unlocked' state:
- */
-#ifndef CONFIG_DEBUG_MUTEXES
- /*
- * When debugging is enabled we must not clear the owner before time,
- * the slow path will always be taken, and that clears the owner field
- * after verifying that it was indeed current.
- */
- mutex_clear_owner(lock);
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+ if (__mutex_unlock_fast(lock))
+ return;
#endif
- __mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
+ __mutex_unlock_slowpath(lock, _RET_IP_);
}
-
EXPORT_SYMBOL(mutex_unlock);
/**
@@ -465,15 +589,7 @@ void __sched ww_mutex_unlock(struct ww_mutex *lock)
lock->ctx = NULL;
}
-#ifndef CONFIG_DEBUG_MUTEXES
- /*
- * When debugging is enabled we must not clear the owner before time,
- * the slow path will always be taken, and that clears the owner field
- * after verifying that it was indeed current.
- */
- mutex_clear_owner(&lock->base);
-#endif
- __mutex_fastpath_unlock(&lock->base.count, __mutex_unlock_slowpath);
+ mutex_unlock(&lock->base);
}
EXPORT_SYMBOL(ww_mutex_unlock);
@@ -509,10 +625,12 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
struct task_struct *task = current;
struct mutex_waiter waiter;
unsigned long flags;
+ bool first = false;
+ struct ww_mutex *ww;
int ret;
if (use_ww_ctx) {
- struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+ ww = container_of(lock, struct ww_mutex, base);
if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
return -EALREADY;
}
@@ -520,20 +638,21 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
preempt_disable();
mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
- if (mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx)) {
+ if (__mutex_trylock(lock, false) ||
+ mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, false)) {
/* got the lock, yay! */
+ lock_acquired(&lock->dep_map, ip);
+ if (use_ww_ctx)
+ ww_mutex_set_context_fastpath(ww, ww_ctx);
preempt_enable();
return 0;
}
spin_lock_mutex(&lock->wait_lock, flags);
-
/*
- * Once more, try to acquire the lock. Only try-lock the mutex if
- * it is unlocked to reduce unnecessary xchg() operations.
+ * After waiting to acquire the wait_lock, try again.
*/
- if (!mutex_is_locked(lock) &&
- (atomic_xchg_acquire(&lock->count, 0) == 1))
+ if (__mutex_trylock(lock, false))
goto skip_wait;
debug_mutex_lock_common(lock, &waiter);
@@ -543,26 +662,26 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
list_add_tail(&waiter.list, &lock->wait_list);
waiter.task = task;
+ if (__mutex_waiter_is_first(lock, &waiter))
+ __mutex_set_flag(lock, MUTEX_FLAG_WAITERS);
+
lock_contended(&lock->dep_map, ip);
+ set_task_state(task, state);
for (;;) {
/*
- * Lets try to take the lock again - this is needed even if
- * we get here for the first time (shortly after failing to
- * acquire the lock), to make sure that we get a wakeup once
- * 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. We only attempt the xchg if the count is
- * non-negative in order to avoid unnecessary xchg operations:
+ * Once we hold wait_lock, we're serialized against
+ * mutex_unlock() handing the lock off to us, do a trylock
+ * before testing the error conditions to make sure we pick up
+ * the handoff.
*/
- if (atomic_read(&lock->count) >= 0 &&
- (atomic_xchg_acquire(&lock->count, -1) == 1))
- break;
+ if (__mutex_trylock(lock, first))
+ goto acquired;
/*
- * got a signal? (This code gets eliminated in the
- * TASK_UNINTERRUPTIBLE case.)
+ * Check for signals and wound conditions while holding
+ * wait_lock. This ensures the lock cancellation is ordered
+ * against mutex_unlock() and wake-ups do not go missing.
*/
if (unlikely(signal_pending_state(state, task))) {
ret = -EINTR;
@@ -575,36 +694,49 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
goto err;
}
- __set_task_state(task, state);
-
- /* didn't get the lock, go to sleep: */
spin_unlock_mutex(&lock->wait_lock, flags);
schedule_preempt_disabled();
+
+ if (!first && __mutex_waiter_is_first(lock, &waiter)) {
+ first = true;
+ __mutex_set_flag(lock, MUTEX_FLAG_HANDOFF);
+ }
+
+ set_task_state(task, state);
+ /*
+ * Here we order against unlock; we must either see it change
+ * state back to RUNNING and fall through the next schedule(),
+ * or we must see its unlock and acquire.
+ */
+ if ((first && mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, true)) ||
+ __mutex_trylock(lock, first))
+ break;
+
spin_lock_mutex(&lock->wait_lock, flags);
}
+ spin_lock_mutex(&lock->wait_lock, flags);
+acquired:
__set_task_state(task, TASK_RUNNING);
mutex_remove_waiter(lock, &waiter, task);
- /* set it to 0 if there are no waiters left: */
if (likely(list_empty(&lock->wait_list)))
- atomic_set(&lock->count, 0);
+ __mutex_clear_flag(lock, MUTEX_FLAGS);
+
debug_mutex_free_waiter(&waiter);
skip_wait:
/* got the lock - cleanup and rejoice! */
lock_acquired(&lock->dep_map, ip);
- mutex_set_owner(lock);
- if (use_ww_ctx) {
- struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+ if (use_ww_ctx)
ww_mutex_set_context_slowpath(ww, ww_ctx);
- }
spin_unlock_mutex(&lock->wait_lock, flags);
preempt_enable();
return 0;
err:
+ __set_task_state(task, TASK_RUNNING);
mutex_remove_waiter(lock, &waiter, task);
spin_unlock_mutex(&lock->wait_lock, flags);
debug_mutex_free_waiter(&waiter);
@@ -631,7 +763,6 @@ _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
0, nest, _RET_IP_, NULL, 0);
}
-
EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
int __sched
@@ -650,7 +781,6 @@ mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
subclass, NULL, _RET_IP_, NULL, 0);
}
-
EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
static inline int
@@ -715,54 +845,64 @@ EXPORT_SYMBOL_GPL(__ww_mutex_lock_interruptible);
/*
* Release the lock, slowpath:
*/
-static inline void
-__mutex_unlock_common_slowpath(struct mutex *lock, int nested)
+static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigned long ip)
{
- unsigned long flags;
- WAKE_Q(wake_q);
+ struct task_struct *next = NULL;
+ unsigned long owner, flags;
+ DEFINE_WAKE_Q(wake_q);
+
+ mutex_release(&lock->dep_map, 1, ip);
/*
- * As a performance measurement, release the lock before doing other
- * wakeup related duties to follow. This allows other tasks to acquire
- * the lock sooner, while still handling cleanups in past unlock calls.
- * This can be done as we do not enforce strict equivalence between the
- * mutex counter and wait_list.
- *
+ * Release the lock before (potentially) taking the spinlock such that
+ * other contenders can get on with things ASAP.
*
- * Some architectures leave the lock unlocked in the fastpath failure
- * case, others need to leave it locked. In the later case we have to
- * unlock it here - as the lock counter is currently 0 or negative.
+ * Except when HANDOFF, in that case we must not clear the owner field,
+ * but instead set it to the top waiter.
*/
- if (__mutex_slowpath_needs_to_unlock())
- atomic_set(&lock->count, 1);
+ owner = atomic_long_read(&lock->owner);
+ for (;;) {
+ unsigned long old;
+
+#ifdef CONFIG_DEBUG_MUTEXES
+ DEBUG_LOCKS_WARN_ON(__owner_task(owner) != current);
+#endif
+
+ if (owner & MUTEX_FLAG_HANDOFF)
+ break;
+
+ old = atomic_long_cmpxchg_release(&lock->owner, owner,
+ __owner_flags(owner));
+ if (old == owner) {
+ if (owner & MUTEX_FLAG_WAITERS)
+ break;
+
+ return;
+ }
+
+ owner = old;
+ }
spin_lock_mutex(&lock->wait_lock, flags);
- mutex_release(&lock->dep_map, nested, _RET_IP_);
debug_mutex_unlock(lock);
-
if (!list_empty(&lock->wait_list)) {
/* get the first entry from the wait-list: */
struct mutex_waiter *waiter =
- list_entry(lock->wait_list.next,
- struct mutex_waiter, list);
+ list_first_entry(&lock->wait_list,
+ struct mutex_waiter, list);
+
+ next = waiter->task;
debug_mutex_wake_waiter(lock, waiter);
- wake_q_add(&wake_q, waiter->task);
+ wake_q_add(&wake_q, next);
}
- spin_unlock_mutex(&lock->wait_lock, flags);
- wake_up_q(&wake_q);
-}
+ if (owner & MUTEX_FLAG_HANDOFF)
+ __mutex_handoff(lock, next);
-/*
- * Release the lock, slowpath:
- */
-__visible void
-__mutex_unlock_slowpath(atomic_t *lock_count)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
+ spin_unlock_mutex(&lock->wait_lock, flags);
- __mutex_unlock_common_slowpath(lock, 1);
+ wake_up_q(&wake_q);
}
#ifndef CONFIG_DEBUG_LOCK_ALLOC
@@ -789,38 +929,30 @@ __mutex_lock_interruptible_slowpath(struct mutex *lock);
*/
int __sched mutex_lock_interruptible(struct mutex *lock)
{
- int ret;
-
might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->count);
- if (likely(!ret)) {
- mutex_set_owner(lock);
+
+ if (__mutex_trylock_fast(lock))
return 0;
- } else
- return __mutex_lock_interruptible_slowpath(lock);
+
+ return __mutex_lock_interruptible_slowpath(lock);
}
EXPORT_SYMBOL(mutex_lock_interruptible);
int __sched mutex_lock_killable(struct mutex *lock)
{
- int ret;
-
might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->count);
- if (likely(!ret)) {
- mutex_set_owner(lock);
+
+ if (__mutex_trylock_fast(lock))
return 0;
- } else
- return __mutex_lock_killable_slowpath(lock);
+
+ return __mutex_lock_killable_slowpath(lock);
}
EXPORT_SYMBOL(mutex_lock_killable);
-__visible void __sched
-__mutex_lock_slowpath(atomic_t *lock_count)
+static noinline void __sched
+__mutex_lock_slowpath(struct mutex *lock)
{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
-
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0,
NULL, _RET_IP_, NULL, 0);
}
@@ -856,37 +988,6 @@ __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
#endif
-/*
- * Spinlock based trylock, we take the spinlock and check whether we
- * can get the lock:
- */
-static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, 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_acquire(&lock->count, -1);
- if (likely(prev == 1)) {
- mutex_set_owner(lock);
- mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
- }
-
- /* Set it back to 0 if there are no waiters: */
- if (likely(list_empty(&lock->wait_list)))
- atomic_set(&lock->count, 0);
-
- spin_unlock_mutex(&lock->wait_lock, flags);
-
- return prev == 1;
-}
-
/**
* mutex_trylock - try to acquire the mutex, without waiting
* @lock: the mutex to be acquired
@@ -903,13 +1004,12 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
*/
int __sched mutex_trylock(struct mutex *lock)
{
- int ret;
+ bool locked = __mutex_trylock(lock, false);
- ret = __mutex_fastpath_trylock(&lock->count, __mutex_trylock_slowpath);
- if (ret)
- mutex_set_owner(lock);
+ if (locked)
+ mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
- return ret;
+ return locked;
}
EXPORT_SYMBOL(mutex_trylock);
@@ -917,36 +1017,28 @@ EXPORT_SYMBOL(mutex_trylock);
int __sched
__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
{
- int ret;
-
might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
- if (likely(!ret)) {
+ if (__mutex_trylock_fast(&lock->base)) {
ww_mutex_set_context_fastpath(lock, ctx);
- mutex_set_owner(&lock->base);
- } else
- ret = __ww_mutex_lock_slowpath(lock, ctx);
- return ret;
+ return 0;
+ }
+
+ return __ww_mutex_lock_slowpath(lock, ctx);
}
EXPORT_SYMBOL(__ww_mutex_lock);
int __sched
__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
{
- int ret;
-
might_sleep();
- ret = __mutex_fastpath_lock_retval(&lock->base.count);
-
- if (likely(!ret)) {
+ if (__mutex_trylock_fast(&lock->base)) {
ww_mutex_set_context_fastpath(lock, ctx);
- mutex_set_owner(&lock->base);
- } else
- ret = __ww_mutex_lock_interruptible_slowpath(lock, ctx);
- return ret;
+ return 0;
+ }
+
+ return __ww_mutex_lock_interruptible_slowpath(lock, ctx);
}
EXPORT_SYMBOL(__ww_mutex_lock_interruptible);
diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h
index 6cd6b8e9efd7..4410a4af42a3 100644
--- a/kernel/locking/mutex.h
+++ b/kernel/locking/mutex.h
@@ -16,32 +16,6 @@
#define mutex_remove_waiter(lock, waiter, task) \
__list_del((waiter)->list.prev, (waiter)->list.next)
-#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-/*
- * The mutex owner can get read and written to locklessly.
- * We should use WRITE_ONCE when writing the owner value to
- * avoid store tearing, otherwise, a thread could potentially
- * read a partially written and incomplete owner value.
- */
-static inline void mutex_set_owner(struct mutex *lock)
-{
- WRITE_ONCE(lock->owner, current);
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
- WRITE_ONCE(lock->owner, NULL);
-}
-#else
-static inline void mutex_set_owner(struct mutex *lock)
-{
-}
-
-static inline void mutex_clear_owner(struct mutex *lock)
-{
-}
-#endif
-
#define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
#define debug_mutex_free_waiter(waiter) do { } while (0)
#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c
index 05a37857ab55..a3167941093b 100644
--- a/kernel/locking/osq_lock.c
+++ b/kernel/locking/osq_lock.c
@@ -21,6 +21,11 @@ static inline int encode_cpu(int cpu_nr)
return cpu_nr + 1;
}
+static inline int node_cpu(struct optimistic_spin_node *node)
+{
+ return node->cpu - 1;
+}
+
static inline struct optimistic_spin_node *decode_cpu(int encoded_cpu_val)
{
int cpu_nr = encoded_cpu_val - 1;
@@ -75,7 +80,7 @@ osq_wait_next(struct optimistic_spin_queue *lock,
break;
}
- cpu_relax_lowlatency();
+ cpu_relax();
}
return next;
@@ -118,11 +123,13 @@ bool osq_lock(struct optimistic_spin_queue *lock)
while (!READ_ONCE(node->locked)) {
/*
* If we need to reschedule bail... so we can block.
+ * Use vcpu_is_preempted() to avoid waiting for a preempted
+ * lock holder:
*/
- if (need_resched())
+ if (need_resched() || vcpu_is_preempted(node_cpu(node->prev)))
goto unqueue;
- cpu_relax_lowlatency();
+ cpu_relax();
}
return true;
@@ -148,7 +155,7 @@ bool osq_lock(struct optimistic_spin_queue *lock)
if (smp_load_acquire(&node->locked))
return true;
- cpu_relax_lowlatency();
+ cpu_relax();
/*
* Or we race against a concurrent unqueue()'s step-B, in which
diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c
index 19248ddf37ce..cc3ed0ccdfa2 100644
--- a/kernel/locking/qrwlock.c
+++ b/kernel/locking/qrwlock.c
@@ -54,7 +54,7 @@ static __always_inline void
rspin_until_writer_unlock(struct qrwlock *lock, u32 cnts)
{
while ((cnts & _QW_WMASK) == _QW_LOCKED) {
- cpu_relax_lowlatency();
+ cpu_relax();
cnts = atomic_read_acquire(&lock->cnts);
}
}
@@ -130,7 +130,7 @@ void queued_write_lock_slowpath(struct qrwlock *lock)
(cmpxchg_relaxed(&l->wmode, 0, _QW_WAITING) == 0))
break;
- cpu_relax_lowlatency();
+ cpu_relax();
}
/* When no more readers, set the locked flag */
@@ -141,7 +141,7 @@ void queued_write_lock_slowpath(struct qrwlock *lock)
_QW_LOCKED) == _QW_WAITING))
break;
- cpu_relax_lowlatency();
+ cpu_relax();
}
unlock:
arch_spin_unlock(&lock->wait_lock);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 2c49d76f96c3..2f443ed2320a 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1446,7 +1446,7 @@ rt_mutex_fastunlock(struct rt_mutex *lock,
bool (*slowfn)(struct rt_mutex *lock,
struct wake_q_head *wqh))
{
- WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_q);
if (likely(rt_mutex_cmpxchg_release(lock, current, NULL))) {
rt_mutex_deadlock_account_unlock(current);
@@ -1619,11 +1619,15 @@ EXPORT_SYMBOL_GPL(__rt_mutex_init);
* rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
* proxy owner
*
- * @lock: the rt_mutex to be locked
+ * @lock: the rt_mutex to be locked
* @proxy_owner:the task to set as owner
*
* No locking. Caller has to do serializing itself
- * Special API call for PI-futex support
+ *
+ * Special API call for PI-futex support. This initializes the rtmutex and
+ * assigns it to @proxy_owner. Concurrent operations on the rtmutex are not
+ * possible at this point because the pi_state which contains the rtmutex
+ * is not yet visible to other tasks.
*/
void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner)
@@ -1637,10 +1641,14 @@ void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
/**
* rt_mutex_proxy_unlock - release a lock on behalf of owner
*
- * @lock: the rt_mutex to be locked
+ * @lock: the rt_mutex to be locked
*
* No locking. Caller has to do serializing itself
- * Special API call for PI-futex support
+ *
+ * Special API call for PI-futex support. This merrily cleans up the rtmutex
+ * (debugging) state. Concurrent operations on this rt_mutex are not
+ * possible because it belongs to the pi_state which is about to be freed
+ * and it is not longer visible to other tasks.
*/
void rt_mutex_proxy_unlock(struct rt_mutex *lock,
struct task_struct *proxy_owner)
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index e317e1cbb3eb..990134617b4c 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -71,13 +71,12 @@ task_top_pi_waiter(struct task_struct *p)
* lock->owner state tracking:
*/
#define RT_MUTEX_HAS_WAITERS 1UL
-#define RT_MUTEX_OWNER_MASKALL 1UL
static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
{
unsigned long owner = (unsigned long) READ_ONCE(lock->owner);
- return (struct task_struct *) (owner & ~RT_MUTEX_OWNER_MASKALL);
+ return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);
}
/*
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 2337b4bb2366..631506004f9e 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -225,7 +225,7 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem)
long count, adjustment = -RWSEM_ACTIVE_READ_BIAS;
struct rwsem_waiter waiter;
struct task_struct *tsk = current;
- WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_q);
waiter.task = tsk;
waiter.type = RWSEM_WAITING_FOR_READ;
@@ -336,7 +336,11 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
goto done;
}
- ret = owner->on_cpu;
+ /*
+ * As lock holder preemption issue, we both skip spinning if task is not
+ * on cpu or its cpu is preempted
+ */
+ ret = owner->on_cpu && !vcpu_is_preempted(task_cpu(owner));
done:
rcu_read_unlock();
return ret;
@@ -362,13 +366,17 @@ static noinline bool rwsem_spin_on_owner(struct rw_semaphore *sem)
*/
barrier();
- /* abort spinning when need_resched or owner is not running */
- if (!owner->on_cpu || need_resched()) {
+ /*
+ * abort spinning when need_resched or owner is not running or
+ * owner's cpu is preempted.
+ */
+ if (!owner->on_cpu || need_resched() ||
+ vcpu_is_preempted(task_cpu(owner))) {
rcu_read_unlock();
return false;
}
- cpu_relax_lowlatency();
+ cpu_relax();
}
rcu_read_unlock();
out:
@@ -423,7 +431,7 @@ 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.
*/
- cpu_relax_lowlatency();
+ cpu_relax();
}
osq_unlock(&sem->osq);
done:
@@ -461,7 +469,7 @@ __rwsem_down_write_failed_common(struct rw_semaphore *sem, int state)
bool waiting = true; /* any queued threads before us */
struct rwsem_waiter waiter;
struct rw_semaphore *ret = sem;
- WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_q);
/* undo write bias from down_write operation, stop active locking */
count = atomic_long_sub_return(RWSEM_ACTIVE_WRITE_BIAS, &sem->count);
@@ -495,7 +503,7 @@ __rwsem_down_write_failed_common(struct rw_semaphore *sem, int state)
* wake any read locks that were queued ahead of us.
*/
if (count > RWSEM_WAITING_BIAS) {
- WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_q);
__rwsem_mark_wake(sem, RWSEM_WAKE_READERS, &wake_q);
/*
@@ -571,7 +579,7 @@ __visible
struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
{
unsigned long flags;
- WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_q);
/*
* If a spinner is present, it is not necessary to do the wakeup.
@@ -625,7 +633,7 @@ __visible
struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
{
unsigned long flags;
- WAKE_Q(wake_q);
+ DEFINE_WAKE_Q(wake_q);
raw_spin_lock_irqsave(&sem->wait_lock, flags);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 154fd689fe02..8b08fb257856 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -75,11 +75,11 @@
#include <linux/compiler.h>
#include <linux/frame.h>
#include <linux/prefetch.h>
+#include <linux/mutex.h>
#include <asm/switch_to.h>
#include <asm/tlb.h>
#include <asm/irq_regs.h>
-#include <asm/mutex.h>
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#endif
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index ec9ab2f01489..1eb82661ecdb 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -194,7 +194,7 @@ static int multi_cpu_stop(void *data)
/* Simple state machine */
do {
/* Chill out and ensure we re-read multi_stop_state. */
- cpu_relax();
+ cpu_relax_yield();
if (msdata->state != curstate) {
curstate = msdata->state;
switch (curstate) {
diff --git a/lib/lockref.c b/lib/lockref.c
index 5a92189ad711..c4bfcb8836cd 100644
--- a/lib/lockref.c
+++ b/lib/lockref.c
@@ -20,7 +20,7 @@
if (likely(old.lock_count == prev.lock_count)) { \
SUCCESS; \
} \
- cpu_relax_lowlatency(); \
+ cpu_relax(); \
} \
} while (0)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index a8368d1c4348..23f462f64a3f 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6076,6 +6076,12 @@ sub process {
}
}
+# check for mutex_trylock_recursive usage
+ if ($line =~ /mutex_trylock_recursive/) {
+ ERROR("LOCKING",
+ "recursive locking is bad, do not use this ever.\n" . $herecurr);
+ }
+
# check for lockdep_set_novalidate_class
if ($line =~ /^.\s*lockdep_set_novalidate_class\s*\(/ ||
$line =~ /__lockdep_no_validate__\s*\)/ ) {
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7f9ee2929cfe..c55f5d6a7767 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1972,30 +1972,38 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
}
EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init);
-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)
{
struct kvm_memslots *slots = kvm_memslots(kvm);
int r;
+ gpa_t gpa = ghc->gpa + offset;
- BUG_ON(len > ghc->len);
+ BUG_ON(len + offset > ghc->len);
if (slots->generation != ghc->generation)
kvm_gfn_to_hva_cache_init(kvm, ghc, ghc->gpa, ghc->len);
if (unlikely(!ghc->memslot))
- return kvm_write_guest(kvm, ghc->gpa, data, len);
+ return kvm_write_guest(kvm, gpa, data, len);
if (kvm_is_error_hva(ghc->hva))
return -EFAULT;
- r = __copy_to_user((void __user *)ghc->hva, data, len);
+ r = __copy_to_user((void __user *)ghc->hva + offset, data, len);
if (r)
return -EFAULT;
- mark_page_dirty_in_slot(ghc->memslot, ghc->gpa >> PAGE_SHIFT);
+ mark_page_dirty_in_slot(ghc->memslot, gpa >> PAGE_SHIFT);
return 0;
}
+EXPORT_SYMBOL_GPL(kvm_write_guest_offset_cached);
+
+int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
+ void *data, unsigned long len)
+{
+ return kvm_write_guest_offset_cached(kvm, ghc, data, 0, len);
+}
EXPORT_SYMBOL_GPL(kvm_write_guest_cached);
int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
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