diff options
46 files changed, 584 insertions, 212 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index e55124e7c40c..e1d28fbf7570 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -320,10 +320,11 @@ This file shows up if CONFIG_DETECT_HUNG_TASK is enabled. ============================================================== -hung_task_warning: +hung_task_warnings: The maximum number of warnings to report. During a check interval -When this value is reached, no more the warnings will be reported. +if a hung task is detected, this value is decreased by 1. +When this value reaches 0, no more warnings will be reported. This file shows up if CONFIG_DETECT_HUNG_TASK is enabled. -1: report an infinite number of warnings. diff --git a/arch/alpha/include/asm/Kbuild b/arch/alpha/include/asm/Kbuild index a73a8e208a4a..7736f426ff3b 100644 --- a/arch/alpha/include/asm/Kbuild +++ b/arch/alpha/include/asm/Kbuild @@ -1,7 +1,8 @@ -generic-y += clkdev.h +generic-y += clkdev.h generic-y += exec.h -generic-y += trace_clock.h -generic-y += preempt.h generic-y += hash.h +generic-y += mcs_spinlock.h +generic-y += preempt.h +generic-y += trace_clock.h diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild index 0d3362991c31..e76fd79f32b0 100644 --- a/arch/arc/include/asm/Kbuild +++ b/arch/arc/include/asm/Kbuild @@ -1,15 +1,15 @@ generic-y += auxvec.h generic-y += barrier.h -generic-y += bugs.h generic-y += bitsperlong.h +generic-y += bugs.h generic-y += clkdev.h generic-y += cputime.h generic-y += device.h generic-y += div64.h generic-y += emergency-restart.h generic-y += errno.h -generic-y += fcntl.h generic-y += fb.h +generic-y += fcntl.h generic-y += ftrace.h generic-y += hardirq.h generic-y += hash.h @@ -22,6 +22,7 @@ generic-y += kmap_types.h generic-y += kvm_para.h generic-y += local.h generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += mman.h generic-y += msgbuf.h generic-y += param.h @@ -30,6 +31,7 @@ generic-y += pci.h generic-y += percpu.h generic-y += poll.h generic-y += posix_types.h +generic-y += preempt.h generic-y += resource.h generic-y += scatterlist.h generic-y += sembuf.h @@ -48,4 +50,3 @@ generic-y += ucontext.h generic-y += user.h generic-y += vga.h generic-y += xor.h -generic-y += preempt.h diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild index 3278afe2c3ab..23e728ecf8ab 100644 --- a/arch/arm/include/asm/Kbuild +++ b/arch/arm/include/asm/Kbuild @@ -7,16 +7,19 @@ generic-y += current.h generic-y += emergency-restart.h generic-y += errno.h generic-y += exec.h +generic-y += hash.h generic-y += ioctl.h generic-y += ipcbuf.h generic-y += irq_regs.h generic-y += kdebug.h generic-y += local.h generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += msgbuf.h generic-y += param.h generic-y += parport.h generic-y += poll.h +generic-y += preempt.h generic-y += resource.h generic-y += sections.h generic-y += segment.h @@ -33,5 +36,3 @@ generic-y += termios.h generic-y += timex.h generic-y += trace_clock.h generic-y += unaligned.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild index 71c53ecfcc3a..3bdfdda70567 100644 --- a/arch/arm64/include/asm/Kbuild +++ b/arch/arm64/include/asm/Kbuild @@ -12,6 +12,7 @@ generic-y += dma.h generic-y += emergency-restart.h generic-y += errno.h generic-y += ftrace.h +generic-y += hash.h generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h @@ -22,12 +23,14 @@ generic-y += kmap_types.h generic-y += kvm_para.h generic-y += local.h generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += mman.h generic-y += msgbuf.h generic-y += mutex.h generic-y += pci.h generic-y += poll.h generic-y += posix_types.h +generic-y += preempt.h generic-y += resource.h generic-y += scatterlist.h generic-y += sections.h @@ -38,8 +41,8 @@ generic-y += shmbuf.h generic-y += sizes.h generic-y += socket.h generic-y += sockios.h -generic-y += switch_to.h generic-y += swab.h +generic-y += switch_to.h generic-y += termbits.h generic-y += termios.h generic-y += topology.h @@ -49,5 +52,3 @@ generic-y += unaligned.h generic-y += user.h generic-y += vga.h generic-y += xor.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/avr32/include/asm/Kbuild b/arch/avr32/include/asm/Kbuild index c7c64a63c29f..00a0f3ccd6eb 100644 --- a/arch/avr32/include/asm/Kbuild +++ b/arch/avr32/include/asm/Kbuild @@ -1,22 +1,23 @@ -generic-y += clkdev.h -generic-y += cputime.h -generic-y += delay.h -generic-y += device.h -generic-y += div64.h -generic-y += emergency-restart.h -generic-y += exec.h -generic-y += futex.h -generic-y += preempt.h -generic-y += irq_regs.h -generic-y += param.h -generic-y += local.h -generic-y += local64.h -generic-y += percpu.h -generic-y += scatterlist.h -generic-y += sections.h -generic-y += topology.h -generic-y += trace_clock.h +generic-y += clkdev.h +generic-y += cputime.h +generic-y += delay.h +generic-y += device.h +generic-y += div64.h +generic-y += emergency-restart.h +generic-y += exec.h +generic-y += futex.h +generic-y += hash.h +generic-y += irq_regs.h +generic-y += local.h +generic-y += local64.h +generic-y += mcs_spinlock.h +generic-y += param.h +generic-y += percpu.h +generic-y += preempt.h +generic-y += scatterlist.h +generic-y += sections.h +generic-y += topology.h +generic-y += trace_clock.h generic-y += vga.h -generic-y += xor.h -generic-y += hash.h +generic-y += xor.h diff --git a/arch/blackfin/include/asm/Kbuild b/arch/blackfin/include/asm/Kbuild index 359d36fdc247..0d93b9a79ca9 100644 --- a/arch/blackfin/include/asm/Kbuild +++ b/arch/blackfin/include/asm/Kbuild @@ -10,6 +10,7 @@ generic-y += emergency-restart.h generic-y += errno.h generic-y += fb.h generic-y += futex.h +generic-y += hash.h generic-y += hw_irq.h generic-y += ioctl.h generic-y += ipcbuf.h @@ -17,14 +18,16 @@ generic-y += irq_regs.h generic-y += kdebug.h generic-y += kmap_types.h generic-y += kvm_para.h -generic-y += local64.h generic-y += local.h +generic-y += local64.h +generic-y += mcs_spinlock.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 +generic-y += preempt.h generic-y += resource.h generic-y += scatterlist.h generic-y += sembuf.h @@ -44,5 +47,3 @@ generic-y += ucontext.h generic-y += unaligned.h generic-y += user.h generic-y += xor.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/c6x/include/asm/Kbuild b/arch/c6x/include/asm/Kbuild index d73bb85ccdd3..8dbdce8421b0 100644 --- a/arch/c6x/include/asm/Kbuild +++ b/arch/c6x/include/asm/Kbuild @@ -15,6 +15,7 @@ generic-y += exec.h generic-y += fb.h generic-y += fcntl.h generic-y += futex.h +generic-y += hash.h generic-y += hw_irq.h generic-y += io.h generic-y += ioctl.h @@ -24,6 +25,7 @@ generic-y += irq_regs.h generic-y += kdebug.h generic-y += kmap_types.h generic-y += local.h +generic-y += mcs_spinlock.h generic-y += mman.h generic-y += mmu.h generic-y += mmu_context.h @@ -34,6 +36,7 @@ generic-y += percpu.h generic-y += pgalloc.h generic-y += poll.h generic-y += posix_types.h +generic-y += preempt.h generic-y += resource.h generic-y += scatterlist.h generic-y += segment.h @@ -56,5 +59,3 @@ generic-y += ucontext.h generic-y += user.h generic-y += vga.h generic-y += xor.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/cris/include/asm/Kbuild b/arch/cris/include/asm/Kbuild index f3fd8768f095..056027f38351 100644 --- a/arch/cris/include/asm/Kbuild +++ b/arch/cris/include/asm/Kbuild @@ -9,8 +9,9 @@ generic-y += exec.h generic-y += hash.h generic-y += kvm_para.h generic-y += linkage.h +generic-y += mcs_spinlock.h generic-y += module.h +generic-y += preempt.h generic-y += trace_clock.h generic-y += vga.h generic-y += xor.h -generic-y += preempt.h diff --git a/arch/frv/include/asm/Kbuild b/arch/frv/include/asm/Kbuild index bc42f14c9c2e..babb9338ebf8 100644 --- a/arch/frv/include/asm/Kbuild +++ b/arch/frv/include/asm/Kbuild @@ -1,6 +1,7 @@ generic-y += clkdev.h generic-y += exec.h -generic-y += trace_clock.h -generic-y += preempt.h generic-y += hash.h +generic-y += mcs_spinlock.h +generic-y += preempt.h +generic-y += trace_clock.h diff --git a/arch/hexagon/include/asm/Kbuild b/arch/hexagon/include/asm/Kbuild index 38ca45d3df1e..eadcc118f950 100644 --- a/arch/hexagon/include/asm/Kbuild +++ b/arch/hexagon/include/asm/Kbuild @@ -25,14 +25,16 @@ generic-y += ipcbuf.h generic-y += irq_regs.h generic-y += kdebug.h generic-y += kmap_types.h -generic-y += local64.h generic-y += local.h +generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += mman.h generic-y += msgbuf.h generic-y += pci.h generic-y += percpu.h generic-y += poll.h generic-y += posix_types.h +generic-y += preempt.h generic-y += resource.h generic-y += rwsem.h generic-y += scatterlist.h @@ -45,8 +47,8 @@ generic-y += siginfo.h generic-y += sizes.h generic-y += socket.h generic-y += sockios.h -generic-y += statfs.h generic-y += stat.h +generic-y += statfs.h generic-y += termbits.h generic-y += termios.h generic-y += topology.h @@ -55,4 +57,3 @@ generic-y += types.h generic-y += ucontext.h generic-y += unaligned.h generic-y += xor.h -generic-y += preempt.h diff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild index 283a83154b5e..0da4aa2602ae 100644 --- a/arch/ia64/include/asm/Kbuild +++ b/arch/ia64/include/asm/Kbuild @@ -1,8 +1,9 @@ generic-y += clkdev.h generic-y += exec.h +generic-y += hash.h generic-y += kvm_para.h -generic-y += trace_clock.h +generic-y += mcs_spinlock.h generic-y += preempt.h +generic-y += trace_clock.h generic-y += vtime.h -generic-y += hash.h diff --git a/arch/m32r/include/asm/Kbuild b/arch/m32r/include/asm/Kbuild index 932435ac4e5c..5825a35b2c56 100644 --- a/arch/m32r/include/asm/Kbuild +++ b/arch/m32r/include/asm/Kbuild @@ -1,7 +1,8 @@ generic-y += clkdev.h generic-y += exec.h +generic-y += hash.h +generic-y += mcs_spinlock.h generic-y += module.h -generic-y += trace_clock.h generic-y += preempt.h -generic-y += hash.h +generic-y += trace_clock.h diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig index dbdd2231c75d..b2e322939256 100644 --- a/arch/m68k/Kconfig +++ b/arch/m68k/Kconfig @@ -17,6 +17,7 @@ config M68K select FPU if MMU select ARCH_WANT_IPC_PARSE_VERSION select ARCH_USES_GETTIMEOFFSET if MMU && !COLDFIRE + select HAVE_FUTEX_CMPXCHG if MMU && FUTEX select HAVE_MOD_ARCH_SPECIFIC select MODULES_USE_ELF_REL select MODULES_USE_ELF_RELA diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild index 6fb9e813a910..c67c94a2d672 100644 --- a/arch/m68k/include/asm/Kbuild +++ b/arch/m68k/include/asm/Kbuild @@ -14,8 +14,9 @@ generic-y += irq_regs.h generic-y += kdebug.h generic-y += kmap_types.h generic-y += kvm_para.h -generic-y += local64.h generic-y += local.h +generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += mman.h generic-y += mutex.h generic-y += percpu.h diff --git a/arch/metag/include/asm/Kbuild b/arch/metag/include/asm/Kbuild index b716d807c2ec..c29ead89a317 100644 --- a/arch/metag/include/asm/Kbuild +++ b/arch/metag/include/asm/Kbuild @@ -13,6 +13,7 @@ generic-y += fb.h generic-y += fcntl.h generic-y += futex.h generic-y += hardirq.h +generic-y += hash.h generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h @@ -23,6 +24,7 @@ generic-y += kmap_types.h generic-y += kvm_para.h generic-y += local.h generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += msgbuf.h generic-y += mutex.h generic-y += param.h @@ -30,6 +32,7 @@ generic-y += pci.h generic-y += percpu.h generic-y += poll.h generic-y += posix_types.h +generic-y += preempt.h generic-y += scatterlist.h generic-y += sections.h generic-y += sembuf.h @@ -52,5 +55,3 @@ generic-y += unaligned.h generic-y += user.h generic-y += vga.h generic-y += xor.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild index 2b98bc73642a..1f590ab8f323 100644 --- a/arch/microblaze/include/asm/Kbuild +++ b/arch/microblaze/include/asm/Kbuild @@ -3,6 +3,7 @@ generic-y += barrier.h generic-y += clkdev.h generic-y += exec.h generic-y += hash.h -generic-y += trace_clock.h -generic-y += syscalls.h +generic-y += mcs_spinlock.h generic-y += preempt.h +generic-y += syscalls.h +generic-y += trace_clock.h diff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild index 2d7f65052c1f..05439187891d 100644 --- a/arch/mips/include/asm/Kbuild +++ b/arch/mips/include/asm/Kbuild @@ -2,16 +2,17 @@ generic-y += cputime.h generic-y += current.h generic-y += emergency-restart.h +generic-y += hash.h generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += mutex.h generic-y += parport.h generic-y += percpu.h +generic-y += preempt.h generic-y += scatterlist.h generic-y += sections.h generic-y += segment.h generic-y += serial.h generic-y += trace_clock.h -generic-y += preempt.h generic-y += ucontext.h generic-y += xor.h -generic-y += hash.h diff --git a/arch/mn10300/include/asm/Kbuild b/arch/mn10300/include/asm/Kbuild index 992e989ab785..cbc6b9bf45da 100644 --- a/arch/mn10300/include/asm/Kbuild +++ b/arch/mn10300/include/asm/Kbuild @@ -3,5 +3,6 @@ generic-y += barrier.h generic-y += clkdev.h generic-y += exec.h generic-y += hash.h -generic-y += trace_clock.h +generic-y += mcs_spinlock.h generic-y += preempt.h +generic-y += trace_clock.h diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild index 2e40f1ca8667..480af0d9c2f5 100644 --- a/arch/openrisc/include/asm/Kbuild +++ b/arch/openrisc/include/asm/Kbuild @@ -10,8 +10,8 @@ generic-y += bugs.h generic-y += cacheflush.h generic-y += checksum.h generic-y += clkdev.h -generic-y += cmpxchg.h generic-y += cmpxchg-local.h +generic-y += cmpxchg.h generic-y += cputime.h generic-y += current.h generic-y += device.h @@ -25,6 +25,7 @@ generic-y += fcntl.h generic-y += ftrace.h generic-y += futex.h generic-y += hardirq.h +generic-y += hash.h generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h @@ -34,6 +35,7 @@ generic-y += kdebug.h generic-y += kmap_types.h generic-y += kvm_para.h generic-y += local.h +generic-y += mcs_spinlock.h generic-y += mman.h generic-y += module.h generic-y += msgbuf.h @@ -41,6 +43,7 @@ generic-y += pci.h generic-y += percpu.h generic-y += poll.h generic-y += posix_types.h +generic-y += preempt.h generic-y += resource.h generic-y += scatterlist.h generic-y += sections.h @@ -53,11 +56,11 @@ generic-y += siginfo.h generic-y += signal.h generic-y += socket.h generic-y += sockios.h -generic-y += statfs.h generic-y += stat.h +generic-y += statfs.h generic-y += string.h -generic-y += switch_to.h generic-y += swab.h +generic-y += switch_to.h generic-y += termbits.h generic-y += termios.h generic-y += topology.h @@ -68,5 +71,3 @@ generic-y += user.h generic-y += vga.h generic-y += word-at-a-time.h generic-y += xor.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild index 752c981bc3c7..ecf25e6678ad 100644 --- a/arch/parisc/include/asm/Kbuild +++ b/arch/parisc/include/asm/Kbuild @@ -1,9 +1,29 @@ +generic-y += auxvec.h generic-y += barrier.h -generic-y += word-at-a-time.h auxvec.h user.h cputime.h emergency-restart.h \ - segment.h topology.h vga.h device.h percpu.h hw_irq.h mutex.h \ - div64.h irq_regs.h kdebug.h kvm_para.h local64.h local.h param.h \ - poll.h xor.h clkdev.h exec.h -generic-y += trace_clock.h -generic-y += preempt.h +generic-y += clkdev.h +generic-y += cputime.h +generic-y += device.h +generic-y += div64.h +generic-y += emergency-restart.h +generic-y += exec.h generic-y += hash.h +generic-y += hw_irq.h +generic-y += irq_regs.h +generic-y += kdebug.h +generic-y += kvm_para.h +generic-y += local.h +generic-y += local64.h +generic-y += mcs_spinlock.h +generic-y += mutex.h +generic-y += param.h +generic-y += percpu.h +generic-y += poll.h +generic-y += preempt.h +generic-y += segment.h +generic-y += topology.h +generic-y += trace_clock.h +generic-y += user.h +generic-y += vga.h +generic-y += word-at-a-time.h +generic-y += xor.h diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild index 6c0a955a1b06..3fb1bc432f4f 100644 --- a/arch/powerpc/include/asm/Kbuild +++ b/arch/powerpc/include/asm/Kbuild @@ -1,7 +1,8 @@ generic-y += clkdev.h +generic-y += hash.h +generic-y += mcs_spinlock.h +generic-y += preempt.h generic-y += rwsem.h generic-y += trace_clock.h -generic-y += preempt.h generic-y += vtime.h -generic-y += hash.h diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 65a07750f4f9..bb74b21f007a 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -117,6 +117,7 @@ config S390 select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_TRACE_MCOUNT_TEST + select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_KERNEL_BZIP2 select HAVE_KERNEL_GZIP select HAVE_KERNEL_LZ4 diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild index 8386a4a1f19a..57892a8a9055 100644 --- a/arch/s390/include/asm/Kbuild +++ b/arch/s390/include/asm/Kbuild @@ -1,6 +1,7 @@ generic-y += clkdev.h -generic-y += trace_clock.h -generic-y += preempt.h generic-y += hash.h +generic-y += mcs_spinlock.h +generic-y += preempt.h +generic-y += trace_clock.h diff --git a/arch/score/include/asm/Kbuild b/arch/score/include/asm/Kbuild index 146b9d5e89f8..4630cf217b5b 100644 --- a/arch/score/include/asm/Kbuild +++ b/arch/score/include/asm/Kbuild @@ -1,10 +1,11 @@ header-y += + generic-y += barrier.h generic-y += clkdev.h generic-y += hash.h +generic-y += mcs_spinlock.h +generic-y += preempt.h generic-y += trace_clock.h generic-y += xor.h -generic-y += preempt.h - diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild index 0cd7198a4524..c19e47dacb31 100644 --- a/arch/sh/include/asm/Kbuild +++ b/arch/sh/include/asm/Kbuild @@ -8,18 +8,21 @@ generic-y += emergency-restart.h generic-y += errno.h generic-y += exec.h generic-y += fcntl.h +generic-y += hash.h generic-y += ioctl.h generic-y += ipcbuf.h generic-y += irq_regs.h generic-y += kvm_para.h generic-y += local.h generic-y += local64.h +generic-y += mcs_spinlock.h +generic-y += mman.h +generic-y += msgbuf.h generic-y += param.h generic-y += parport.h generic-y += percpu.h generic-y += poll.h -generic-y += mman.h -generic-y += msgbuf.h +generic-y += preempt.h generic-y += resource.h generic-y += scatterlist.h generic-y += sembuf.h @@ -34,5 +37,3 @@ generic-y += termios.h generic-y += trace_clock.h generic-y += ucontext.h generic-y += xor.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild index 4b60a0c325ec..a45821818003 100644 --- a/arch/sparc/include/asm/Kbuild +++ b/arch/sparc/include/asm/Kbuild @@ -6,15 +6,16 @@ generic-y += cputime.h generic-y += div64.h generic-y += emergency-restart.h generic-y += exec.h -generic-y += linkage.h -generic-y += local64.h -generic-y += mutex.h +generic-y += hash.h generic-y += irq_regs.h +generic-y += linkage.h generic-y += local.h +generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += module.h +generic-y += mutex.h +generic-y += preempt.h generic-y += serial.h generic-y += trace_clock.h generic-y += types.h generic-y += word-at-a-time.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild index 3793c75e45d9..0aa5675e7025 100644 --- a/arch/tile/include/asm/Kbuild +++ b/arch/tile/include/asm/Kbuild @@ -11,6 +11,7 @@ generic-y += errno.h generic-y += exec.h generic-y += fb.h generic-y += fcntl.h +generic-y += hash.h generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h @@ -18,12 +19,14 @@ generic-y += ipcbuf.h generic-y += irq_regs.h generic-y += local.h generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += msgbuf.h generic-y += mutex.h generic-y += param.h generic-y += parport.h generic-y += poll.h generic-y += posix_types.h +generic-y += preempt.h generic-y += resource.h generic-y += scatterlist.h generic-y += sembuf.h @@ -38,5 +41,3 @@ generic-y += termios.h generic-y += trace_clock.h generic-y += types.h generic-y += xor.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild index 88a330dcdede..a5e4b6068213 100644 --- a/arch/um/include/asm/Kbuild +++ b/arch/um/include/asm/Kbuild @@ -1,8 +1,28 @@ -generic-y += bug.h cputime.h device.h emergency-restart.h futex.h hardirq.h -generic-y += hw_irq.h irq_regs.h kdebug.h percpu.h sections.h topology.h xor.h -generic-y += ftrace.h pci.h io.h param.h delay.h mutex.h current.h exec.h -generic-y += switch_to.h clkdev.h -generic-y += trace_clock.h -generic-y += preempt.h -generic-y += hash.h generic-y += barrier.h +generic-y += bug.h +generic-y += clkdev.h +generic-y += cputime.h +generic-y += current.h +generic-y += delay.h +generic-y += device.h +generic-y += emergency-restart.h +generic-y += exec.h +generic-y += ftrace.h +generic-y += futex.h +generic-y += hardirq.h +generic-y += hash.h +generic-y += hw_irq.h +generic-y += io.h +generic-y += irq_regs.h +generic-y += kdebug.h +generic-y += mcs_spinlock.h +generic-y += mutex.h +generic-y += param.h +generic-y += pci.h +generic-y += percpu.h +generic-y += preempt.h +generic-y += sections.h +generic-y += switch_to.h +generic-y += topology.h +generic-y += trace_clock.h +generic-y += xor.h diff --git a/arch/unicore32/include/asm/Kbuild b/arch/unicore32/include/asm/Kbuild index 3ef4f9d9bf5d..1e5fb872a4aa 100644 --- a/arch/unicore32/include/asm/Kbuild +++ b/arch/unicore32/include/asm/Kbuild @@ -16,6 +16,7 @@ generic-y += fcntl.h generic-y += ftrace.h generic-y += futex.h generic-y += hardirq.h +generic-y += hash.h generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h @@ -24,6 +25,7 @@ generic-y += irq_regs.h generic-y += kdebug.h generic-y += kmap_types.h generic-y += local.h +generic-y += mcs_spinlock.h generic-y += mman.h generic-y += module.h generic-y += msgbuf.h @@ -32,6 +34,7 @@ generic-y += parport.h generic-y += percpu.h generic-y += poll.h generic-y += posix_types.h +generic-y += preempt.h generic-y += resource.h generic-y += scatterlist.h generic-y += sections.h @@ -60,5 +63,3 @@ generic-y += unaligned.h generic-y += user.h generic-y += vga.h generic-y += xor.h -generic-y += preempt.h -generic-y += hash.h diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild index 7f669853317a..a8fee078b92f 100644 --- a/arch/x86/include/asm/Kbuild +++ b/arch/x86/include/asm/Kbuild @@ -5,3 +5,4 @@ genhdr-y += unistd_64.h genhdr-y += unistd_x32.h generic-y += clkdev.h +generic-y += mcs_spinlock.h diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild index 0a337e4a8370..c3d20ba6eb86 100644 --- a/arch/xtensa/include/asm/Kbuild +++ b/arch/xtensa/include/asm/Kbuild @@ -9,6 +9,7 @@ generic-y += errno.h generic-y += exec.h generic-y += fcntl.h generic-y += hardirq.h +generic-y += hash.h generic-y += ioctl.h generic-y += irq_regs.h generic-y += kdebug.h @@ -17,7 +18,9 @@ generic-y += kvm_para.h generic-y += linkage.h generic-y += local.h generic-y += local64.h +generic-y += mcs_spinlock.h generic-y += percpu.h +generic-y += preempt.h generic-y += resource.h generic-y += scatterlist.h generic-y += sections.h @@ -27,5 +30,3 @@ generic-y += termios.h generic-y += topology.h generic-y += trace_clock.h generic-y += xor.h -generic-y += preempt.h -generic-y += hash.h diff --git a/drivers/tty/tty_ldsem.c b/drivers/tty/tty_ldsem.c index d8a55e87877f..0ffb0cbe2823 100644 --- a/drivers/tty/tty_ldsem.c +++ b/drivers/tty/tty_ldsem.c @@ -39,17 +39,10 @@ lock_acquire(&(l)->dep_map, s, t, r, c, n, i) # define __rel(l, n, i) \ lock_release(&(l)->dep_map, n, i) -# ifdef CONFIG_PROVE_LOCKING -# define lockdep_acquire(l, s, t, i) __acq(l, s, t, 0, 2, NULL, i) -# define lockdep_acquire_nest(l, s, t, n, i) __acq(l, s, t, 0, 2, n, i) -# define lockdep_acquire_read(l, s, t, i) __acq(l, s, t, 1, 2, NULL, i) -# define lockdep_release(l, n, i) __rel(l, n, i) -# else -# define lockdep_acquire(l, s, t, i) __acq(l, s, t, 0, 1, NULL, i) -# define lockdep_acquire_nest(l, s, t, n, i) __acq(l, s, t, 0, 1, n, i) -# define lockdep_acquire_read(l, s, t, i) __acq(l, s, t, 1, 1, NULL, i) -# define lockdep_release(l, n, i) __rel(l, n, i) -# endif +#define lockdep_acquire(l, s, t, i) __acq(l, s, t, 0, 1, NULL, i) +#define lockdep_acquire_nest(l, s, t, n, i) __acq(l, s, t, 0, 1, n, i) +#define lockdep_acquire_read(l, s, t, i) __acq(l, s, t, 1, 1, NULL, i) +#define lockdep_release(l, n, i) __rel(l, n, i) #else # define lockdep_acquire(l, s, t, i) do { } while (0) # define lockdep_acquire_nest(l, s, t, n, i) do { } while (0) diff --git a/include/asm-generic/mcs_spinlock.h b/include/asm-generic/mcs_spinlock.h new file mode 100644 index 000000000000..10cd4ffc6ba2 --- /dev/null +++ b/include/asm-generic/mcs_spinlock.h @@ -0,0 +1,13 @@ +#ifndef __ASM_MCS_SPINLOCK_H +#define __ASM_MCS_SPINLOCK_H + +/* + * Architectures can define their own: + * + * arch_mcs_spin_lock_contended(l) + * arch_mcs_spin_unlock_contended(l) + * + * See kernel/locking/mcs_spinlock.c. + */ + +#endif /* __ASM_MCS_SPINLOCK_H */ diff --git a/include/linux/futex.h b/include/linux/futex.h index b0d95cac826e..6435f46d6e13 100644 --- a/include/linux/futex.h +++ b/include/linux/futex.h @@ -55,7 +55,11 @@ union futex_key { #ifdef CONFIG_FUTEX extern void exit_robust_list(struct task_struct *curr); extern void exit_pi_state_list(struct task_struct *curr); +#ifdef CONFIG_HAVE_FUTEX_CMPXCHG +#define futex_cmpxchg_enabled 1 +#else extern int futex_cmpxchg_enabled; +#endif #else static inline void exit_robust_list(struct task_struct *curr) { diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 92b1bfc5da60..060e5137fd80 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -252,9 +252,9 @@ struct held_lock { unsigned int trylock:1; /* 16 bits */ unsigned int read:2; /* see lock_acquire() comment */ - unsigned int check:2; /* see lock_acquire() comment */ + unsigned int check:1; /* see lock_acquire() comment */ unsigned int hardirqs_off:1; - unsigned int references:11; /* 32 bits */ + unsigned int references:12; /* 32 bits */ }; /* @@ -303,7 +303,7 @@ extern void lockdep_init_map(struct lockdep_map *lock, const char *name, (lock)->dep_map.key, sub) #define lockdep_set_novalidate_class(lock) \ - lockdep_set_class(lock, &__lockdep_no_validate__) + lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock) /* * Compare locking classes */ @@ -326,9 +326,8 @@ static inline int lockdep_match_key(struct lockdep_map *lock, * * Values for check: * - * 0: disabled - * 1: simple checks (freeing, held-at-exit-time, etc.) - * 2: full validation + * 0: simple checks (freeing, held-at-exit-time, etc.) + * 1: full validation */ extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, int trylock, int read, int check, @@ -479,15 +478,9 @@ static inline void print_irqtrace_events(struct task_struct *curr) * on the per lock-class debug mode: */ -#ifdef CONFIG_PROVE_LOCKING - #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) - #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 2, n, i) - #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 2, n, i) -#else - #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) - #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i) - #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i) -#endif +#define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) +#define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i) +#define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i) #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) @@ -518,13 +511,13 @@ static inline void print_irqtrace_events(struct task_struct *curr) # define might_lock(lock) \ do { \ typecheck(struct lockdep_map *, &(lock)->dep_map); \ - lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \ + lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \ lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ } while (0) # define might_lock_read(lock) \ do { \ typecheck(struct lockdep_map *, &(lock)->dep_map); \ - lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \ + lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \ lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ } while (0) #else diff --git a/include/linux/mutex.h b/include/linux/mutex.h index d3181936c138..11692dea18aa 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -46,6 +46,7 @@ * - detects multi-task circular deadlocks and prints out all affected * locks and tasks (and only those tasks) */ +struct optimistic_spin_queue; struct mutex { /* 1: unlocked, 0: locked, negative: locked, possible waiters */ atomic_t count; @@ -55,7 +56,7 @@ struct mutex { struct task_struct *owner; #endif #ifdef CONFIG_MUTEX_SPIN_ON_OWNER - void *spin_mlock; /* Spinner MCS lock */ + struct optimistic_spin_queue *osq; /* Spinner MCS lock */ #endif #ifdef CONFIG_DEBUG_MUTEXES const char *name; @@ -179,4 +180,4 @@ extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); # define arch_mutex_cpu_relax() cpu_relax() #endif -#endif +#endif /* __LINUX_MUTEX_H */ diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 72bf3a01a4ee..adff3c99dcaa 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -314,7 +314,7 @@ static inline bool rcu_lockdep_current_cpu_online(void) static inline void rcu_lock_acquire(struct lockdep_map *map) { - lock_acquire(map, 0, 0, 2, 1, NULL, _THIS_IP_); + lock_acquire(map, 0, 0, 2, 0, NULL, _THIS_IP_); } static inline void rcu_lock_release(struct lockdep_map *map) diff --git a/init/Kconfig b/init/Kconfig index 009a797dd242..d56cb03c1b49 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1387,6 +1387,13 @@ config FUTEX support for "fast userspace mutexes". The resulting kernel may not run glibc-based applications correctly. +config HAVE_FUTEX_CMPXCHG + bool + help + Architectures should select this if futex_atomic_cmpxchg_inatomic() + is implemented and always working. This removes a couple of runtime + checks. + config EPOLL bool "Enable eventpoll support" if EXPERT default y diff --git a/kernel/futex.c b/kernel/futex.c index 08ec814ad9d2..67dacaf93e56 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -157,7 +157,9 @@ * enqueue. */ +#ifndef CONFIG_HAVE_FUTEX_CMPXCHG int __read_mostly futex_cmpxchg_enabled; +#endif /* * Futex flags used to encode options to functions and preserve them across @@ -2875,9 +2877,28 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, return do_futex(uaddr, op, val, tp, uaddr2, val2, val3); } -static int __init futex_init(void) +static void __init futex_detect_cmpxchg(void) { +#ifndef CONFIG_HAVE_FUTEX_CMPXCHG u32 curval; + + /* + * This will fail and we want it. Some arch implementations do + * runtime detection of the futex_atomic_cmpxchg_inatomic() + * functionality. We want to know that before we call in any + * of the complex code paths. Also we want to prevent + * registration of robust lists in that case. NULL is + * guaranteed to fault and we get -EFAULT on functional + * implementation, the non-functional ones will return + * -ENOSYS. + */ + if (cmpxchg_futex_value_locked(&curval, NULL, 0, 0) == -EFAULT) + futex_cmpxchg_enabled = 1; +#endif +} + +static int __init futex_init(void) +{ unsigned int futex_shift; unsigned long i; @@ -2893,18 +2914,8 @@ static int __init futex_init(void) &futex_shift, NULL, futex_hashsize, futex_hashsize); futex_hashsize = 1UL << futex_shift; - /* - * This will fail and we want it. Some arch implementations do - * runtime detection of the futex_atomic_cmpxchg_inatomic() - * functionality. We want to know that before we call in any - * of the complex code paths. Also we want to prevent - * registration of robust lists in that case. NULL is - * guaranteed to fault and we get -EFAULT on functional - * implementation, the non-functional ones will return - * -ENOSYS. - */ - if (cmpxchg_futex_value_locked(&curval, NULL, 0, 0) == -EFAULT) - futex_cmpxchg_enabled = 1; + + futex_detect_cmpxchg(); for (i = 0; i < futex_hashsize; i++) { atomic_set(&futex_queues[i].waiters, 0); diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile index baab8e5e7f66..2a9ee96ecf00 100644 --- a/kernel/locking/Makefile +++ b/kernel/locking/Makefile @@ -1,5 +1,5 @@ -obj-y += mutex.o semaphore.o rwsem.o lglock.o +obj-y += mutex.o semaphore.o rwsem.o lglock.o mcs_spinlock.o ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_lockdep.o = -pg diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index eb8a54783fa0..bf0c6b0dd9c5 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1936,12 +1936,12 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) for (;;) { int distance = curr->lockdep_depth - depth + 1; - hlock = curr->held_locks + depth-1; + hlock = curr->held_locks + depth - 1; /* * Only non-recursive-read entries get new dependencies * added: */ - if (hlock->read != 2) { + if (hlock->read != 2 && hlock->check) { if (!check_prev_add(curr, hlock, next, distance, trylock_loop)) return 0; @@ -2098,7 +2098,7 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, * (If lookup_chain_cache() returns with 1 it acquires * graph_lock for us) */ - if (!hlock->trylock && (hlock->check == 2) && + if (!hlock->trylock && hlock->check && lookup_chain_cache(curr, hlock, chain_key)) { /* * Check whether last held lock: @@ -2517,7 +2517,7 @@ mark_held_locks(struct task_struct *curr, enum mark_type mark) BUG_ON(usage_bit >= LOCK_USAGE_STATES); - if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys) + if (!hlock->check) continue; if (!mark_lock(curr, hlock, usage_bit)) @@ -3055,9 +3055,6 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, int class_idx; u64 chain_key; - if (!prove_locking) - check = 1; - if (unlikely(!debug_locks)) return 0; @@ -3069,8 +3066,8 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) return 0; - if (lock->key == &__lockdep_no_validate__) - check = 1; + if (!prove_locking || lock->key == &__lockdep_no_validate__) + check = 0; if (subclass < NR_LOCKDEP_CACHING_CLASSES) class = lock->class_cache[subclass]; @@ -3138,7 +3135,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, hlock->holdtime_stamp = lockstat_clock(); #endif - if (check == 2 && !mark_irqflags(curr, hlock)) + if (check && !mark_irqflags(curr, hlock)) return 0; /* mark it as used: */ diff --git a/kernel/locking/mcs_spinlock.c b/kernel/locking/mcs_spinlock.c new file mode 100644 index 000000000000..838dc9e00669 --- /dev/null +++ b/kernel/locking/mcs_spinlock.c @@ -0,0 +1,178 @@ + +#include <linux/percpu.h> +#include <linux/mutex.h> +#include <linux/sched.h> +#include "mcs_spinlock.h" + +#ifdef CONFIG_SMP + +/* + * An MCS like lock especially tailored for optimistic spinning for sleeping + * lock implementations (mutex, rwsem, etc). + * + * Using a single mcs node per CPU is safe because sleeping locks should not be + * called from interrupt context and we have preemption disabled while + * spinning. + */ +static DEFINE_PER_CPU_SHARED_ALIGNED(struct optimistic_spin_queue, osq_node); + +/* + * Get a stable @node->next pointer, either for unlock() or unqueue() purposes. + * Can return NULL in case we were the last queued and we updated @lock instead. + */ +static inline struct optimistic_spin_queue * +osq_wait_next(struct optimistic_spin_queue **lock, + struct optimistic_spin_queue *node, + struct optimistic_spin_queue *prev) +{ + struct optimistic_spin_queue *next = NULL; + + for (;;) { + if (*lock == node && cmpxchg(lock, node, prev) == node) { + /* + * We were the last queued, we moved @lock back. @prev + * will now observe @lock and will complete its + * unlock()/unqueue(). + */ + break; + } + + /* + * We must xchg() the @node->next value, because if we were to + * leave it in, a concurrent unlock()/unqueue() from + * @node->next might complete Step-A and think its @prev is + * still valid. + * + * If the concurrent unlock()/unqueue() wins the race, we'll + * wait for either @lock to point to us, through its Step-B, or + * wait for a new @node->next from its Step-C. + */ + if (node->next) { + next = xchg(&node->next, NULL); + if (next) + break; + } + + arch_mutex_cpu_relax(); + } + + return next; +} + +bool osq_lock(struct optimistic_spin_queue **lock) +{ + struct optimistic_spin_queue *node = this_cpu_ptr(&osq_node); + struct optimistic_spin_queue *prev, *next; + + node->locked = 0; + node->next = NULL; + + node->prev = prev = xchg(lock, node); + if (likely(prev == NULL)) + return true; + + ACCESS_ONCE(prev->next) = node; + + /* + * Normally @prev is untouchable after the above store; because at that + * moment unlock can proceed and wipe the node element from stack. + * + * However, since our nodes are static per-cpu storage, we're + * guaranteed their existence -- this allows us to apply + * cmpxchg in an attempt to undo our queueing. + */ + + while (!smp_load_acquire(&node->locked)) { + /* + * If we need to reschedule bail... so we can block. + */ + if (need_resched()) + goto unqueue; + + arch_mutex_cpu_relax(); + } + return true; + +unqueue: + /* + * Step - A -- stabilize @prev + * + * Undo our @prev->next assignment; this will make @prev's + * unlock()/unqueue() wait for a next pointer since @lock points to us + * (or later). + */ + + for (;;) { + if (prev->next == node && + cmpxchg(&prev->next, node, NULL) == node) + break; + + /* + * We can only fail the cmpxchg() racing against an unlock(), + * in which case we should observe @node->locked becomming + * true. + */ + if (smp_load_acquire(&node->locked)) + return true; + + arch_mutex_cpu_relax(); + + /* + * Or we race against a concurrent unqueue()'s step-B, in which + * case its step-C will write us a new @node->prev pointer. + */ + prev = ACCESS_ONCE(node->prev); + } + + /* + * Step - B -- stabilize @next + * + * Similar to unlock(), wait for @node->next or move @lock from @node + * back to @prev. + */ + + next = osq_wait_next(lock, node, prev); + if (!next) + return false; + + /* + * Step - C -- unlink + * + * @prev is stable because its still waiting for a new @prev->next + * pointer, @next is stable because our @node->next pointer is NULL and + * it will wait in Step-A. + */ + + ACCESS_ONCE(next->prev) = prev; + ACCESS_ONCE(prev->next) = next; + + return false; +} + +void osq_unlock(struct optimistic_spin_queue **lock) +{ + struct optimistic_spin_queue *node = this_cpu_ptr(&osq_node); + struct optimistic_spin_queue *next; + + /* + * Fast path for the uncontended case. + */ + if (likely(cmpxchg(lock, node, NULL) == node)) + return; + + /* + * Second most likely case. + */ + next = xchg(&node->next, NULL); + if (next) { + ACCESS_ONCE(next->locked) = 1; + return; + } + + next = osq_wait_next(lock, node, NULL); + if (next) + ACCESS_ONCE(next->locked) = 1; +} + +#endif + diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h new file mode 100644 index 000000000000..a2dbac4aca6b --- /dev/null +++ b/kernel/locking/mcs_spinlock.h @@ -0,0 +1,129 @@ +/* + * MCS lock defines + * + * This file contains the main data structure and API definitions of MCS lock. + * + * The MCS lock (proposed by Mellor-Crummey and Scott) is a simple spin-lock + * with the desirable properties of being fair, and with each cpu trying + * to acquire the lock spinning on a local variable. + * It avoids expensive cache bouncings that common test-and-set spin-lock + * implementations incur. + */ +#ifndef __LINUX_MCS_SPINLOCK_H +#define __LINUX_MCS_SPINLOCK_H + +#include <asm/mcs_spinlock.h> + +struct mcs_spinlock { + struct mcs_spinlock *next; + int locked; /* 1 if lock acquired */ +}; + +#ifndef arch_mcs_spin_lock_contended +/* + * Using smp_load_acquire() provides a memory barrier that ensures + * subsequent operations happen after the lock is acquired. + */ +#define arch_mcs_spin_lock_contended(l) \ +do { \ + while (!(smp_load_acquire(l))) \ + arch_mutex_cpu_relax(); \ +} while (0) +#endif + +#ifndef arch_mcs_spin_unlock_contended +/* + * smp_store_release() provides a memory barrier to ensure all + * operations in the critical section has been completed before + * unlocking. + */ +#define arch_mcs_spin_unlock_contended(l) \ + smp_store_release((l), 1) +#endif + +/* + * Note: the smp_load_acquire/smp_store_release pair is not + * sufficient to form a full memory barrier across + * cpus for many architectures (except x86) for mcs_unlock and mcs_lock. + * For applications that need a full barrier across multiple cpus + * with mcs_unlock and mcs_lock pair, smp_mb__after_unlock_lock() should be + * used after mcs_lock. + */ + +/* + * In order to acquire the lock, the caller should declare a local node and + * pass a reference of the node to this function in addition to the lock. + * If the lock has already been acquired, then this will proceed to spin + * on this node->locked until the previous lock holder sets the node->locked + * in mcs_spin_unlock(). + * + * We don't inline mcs_spin_lock() so that perf can correctly account for the + * time spent in this lock function. + */ +static inline +void mcs_spin_lock(struct mcs_spinlock **lock, struct mcs_spinlock *node) +{ + struct mcs_spinlock *prev; + + /* Init node */ + node->locked = 0; + node->next = NULL; + + prev = xchg(lock, node); + if (likely(prev == NULL)) { + /* + * Lock acquired, don't need to set node->locked to 1. Threads + * only spin on its own node->locked value for lock acquisition. + * However, since this thread can immediately acquire the lock + * and does not proceed to spin on its own node->locked, this + * value won't be used. If a debug mode is needed to + * audit lock status, then set node->locked value here. + */ + return; + } + ACCESS_ONCE(prev->next) = node; + + /* Wait until the lock holder passes the lock down. */ + arch_mcs_spin_lock_contended(&node->locked); +} + +/* + * Releases the lock. The caller should pass in the corresponding node that + * was used to acquire the lock. + */ +static inline +void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node) +{ + struct mcs_spinlock *next = ACCESS_ONCE(node->next); + + if (likely(!next)) { + /* + * Release the lock by setting it to NULL + */ + if (likely(cmpxchg(lock, node, NULL) == node)) + return; + /* Wait until the next pointer is set */ + while (!(next = ACCESS_ONCE(node->next))) + arch_mutex_cpu_relax(); + } + + /* Pass lock to next waiter. */ + arch_mcs_spin_unlock_contended(&next->locked); +} + +/* + * Cancellable version of the MCS lock above. + * + * Intended for adaptive spinning of sleeping locks: + * mutex_lock()/rwsem_down_{read,write}() etc. + */ + +struct optimistic_spin_queue { + struct optimistic_spin_queue *next, *prev; + int locked; /* 1 if lock acquired */ +}; + +extern bool osq_lock(struct optimistic_spin_queue **lock); +extern void osq_unlock(struct optimistic_spin_queue **lock); + +#endif /* __LINUX_MCS_SPINLOCK_H */ diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c index faf6f5b53e77..e1191c996c59 100644 --- a/kernel/locking/mutex-debug.c +++ b/kernel/locking/mutex-debug.c @@ -83,6 +83,12 @@ void debug_mutex_unlock(struct mutex *lock) DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next); mutex_clear_owner(lock); + + /* + * __mutex_slowpath_needs_to_unlock() is explicitly 0 for debug + * mutexes so that we can do it here after we've verified state. + */ + atomic_set(&lock->count, 1); } void debug_mutex_init(struct mutex *lock, const char *name, diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 4dd6e4c219de..14fe72cc8ce7 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -25,6 +25,7 @@ #include <linux/spinlock.h> #include <linux/interrupt.h> #include <linux/debug_locks.h> +#include "mcs_spinlock.h" /* * In the DEBUG case we are using the "NULL fastpath" for mutexes, @@ -33,6 +34,13 @@ #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> @@ -52,7 +60,7 @@ __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key) INIT_LIST_HEAD(&lock->wait_list); mutex_clear_owner(lock); #ifdef CONFIG_MUTEX_SPIN_ON_OWNER - lock->spin_mlock = NULL; + lock->osq = NULL; #endif debug_mutex_init(lock, name, key); @@ -111,54 +119,7 @@ EXPORT_SYMBOL(mutex_lock); * more or less simultaneously, the spinners need to acquire a MCS lock * first before spinning on the owner field. * - * We don't inline mspin_lock() so that perf can correctly account for the - * time spent in this lock function. */ -struct mspin_node { - struct mspin_node *next ; - int locked; /* 1 if lock acquired */ -}; -#define MLOCK(mutex) ((struct mspin_node **)&((mutex)->spin_mlock)) - -static noinline -void mspin_lock(struct mspin_node **lock, struct mspin_node *node) -{ - struct mspin_node *prev; - - /* Init node */ - node->locked = 0; - node->next = NULL; - - prev = xchg(lock, node); - if (likely(prev == NULL)) { - /* Lock acquired */ - node->locked = 1; - return; - } - ACCESS_ONCE(prev->next) = node; - smp_wmb(); - /* Wait until the lock holder passes the lock down */ - while (!ACCESS_ONCE(node->locked)) - arch_mutex_cpu_relax(); -} - -static void mspin_unlock(struct mspin_node **lock, struct mspin_node *node) -{ - struct mspin_node *next = ACCESS_ONCE(node->next); - - if (likely(!next)) { - /* - * Release the lock by setting it to NULL - */ - if (cmpxchg(lock, node, NULL) == node) - return; - /* Wait until the next pointer is set */ - while (!(next = ACCESS_ONCE(node->next))) - arch_mutex_cpu_relax(); - } - ACCESS_ONCE(next->locked) = 1; - smp_wmb(); -} /* * Mutex spinning code migrated from kernel/sched/core.c @@ -212,6 +173,9 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock) struct task_struct *owner; int retval = 1; + if (need_resched()) + return 0; + rcu_read_lock(); owner = ACCESS_ONCE(lock->owner); if (owner) @@ -446,9 +410,11 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, if (!mutex_can_spin_on_owner(lock)) goto slowpath; + if (!osq_lock(&lock->osq)) + goto slowpath; + for (;;) { struct task_struct *owner; - struct mspin_node node; if (use_ww_ctx && ww_ctx->acquired > 0) { struct ww_mutex *ww; @@ -463,19 +429,16 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, * performed the optimistic spinning cannot be done. */ if (ACCESS_ONCE(ww->ctx)) - goto slowpath; + break; } /* * If there's an owner, wait for it to either * release the lock or go to sleep. */ - mspin_lock(MLOCK(lock), &node); owner = ACCESS_ONCE(lock->owner); - if (owner && !mutex_spin_on_owner(lock, owner)) { - mspin_unlock(MLOCK(lock), &node); - goto slowpath; - } + if (owner && !mutex_spin_on_owner(lock, owner)) + break; if ((atomic_read(&lock->count) == 1) && (atomic_cmpxchg(&lock->count, 1, 0) == 1)) { @@ -488,11 +451,10 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, } mutex_set_owner(lock); - mspin_unlock(MLOCK(lock), &node); + osq_unlock(&lock->osq); preempt_enable(); return 0; } - mspin_unlock(MLOCK(lock), &node); /* * When there's no owner, we might have preempted between the @@ -501,7 +463,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, * the owner complete. */ if (!owner && (need_resched() || rt_task(task))) - goto slowpath; + break; /* * The cpu_relax() call is a compiler barrier which forces @@ -511,7 +473,15 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, */ arch_mutex_cpu_relax(); } + osq_unlock(&lock->osq); slowpath: + /* + * If we fell out of the spin path because of need_resched(), + * reschedule now, before we try-lock the mutex. This avoids getting + * scheduled out right after we obtained the mutex. + */ + if (need_resched()) + schedule_preempt_disabled(); #endif spin_lock_mutex(&lock->wait_lock, flags); @@ -717,10 +687,6 @@ __mutex_unlock_common_slowpath(atomic_t *lock_count, int nested) struct mutex *lock = container_of(lock_count, struct mutex, count); unsigned long flags; - spin_lock_mutex(&lock->wait_lock, flags); - mutex_release(&lock->dep_map, nested, _RET_IP_); - debug_mutex_unlock(lock); - /* * some architectures leave the lock unlocked in the fastpath failure * case, others need to leave it locked. In the later case we have to @@ -729,6 +695,10 @@ __mutex_unlock_common_slowpath(atomic_t *lock_count, int nested) if (__mutex_slowpath_needs_to_unlock()) atomic_set(&lock->count, 1); + 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 = |