| Message ID | 20140606175316.GV13930@laptop.programming.kicks-ass.net (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Fri, 2014-06-06 at 19:53 +0200, Peter Zijlstra wrote: > On Fri, Jun 06, 2014 at 10:22:21AM -0700, Linus Torvalds wrote: > > On Fri, Jun 6, 2014 at 10:11 AM, Peter Zijlstra <peterz@infradead.org> wrote: > > > > > > +config ARCH_NO_ATOMIC_RMW > > > + def_bool y > > > + depends on PARISC || SPARC32 || METAG_ATOMICITY_LOCK1 || (TILE && !TILEGX) || (ARC && !ARC_HAS_LLSC) > > > > Ugh. We've had these kinds of things before, and they are broken and > > nasty to maintain. > > > > Just make it > > > > config ARCH_SUPPORTS_ATOMIC_RMW > > bool > > > > which defaults to no. And then make MUTEX_SPIN_ON_OWNER depend on that. > > --- > Subject: locking, mutex: Make optimistic spinning depend on ARCH_SUPPORTS_ATOMIC_RMW > > The optimistic spin code assumes regular stores and cmpxchg() play nice; > this is found to not be true for at least: parisc, sparc32, tile32, > metag-lock1, arc-!llsc and hexagon. > > There is further wreckage, but this in particular seemed easy to > trigger, so blacklist this. > > Opt in for known good archs. > > Reported-by: Mikulas Patocka <mpatocka@redhat.com> > Signed-off-by: Peter Zijlstra <peterz@infradead.org> > --- > arch/arm/Kconfig | 1 + > arch/arm64/Kconfig | 1 + > arch/powerpc/Kconfig | 1 + > arch/sparc/Kconfig | 1 + > arch/x86/Kconfig | 1 + > kernel/Kconfig.locks | 5 ++++- > 6 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index a2c1a18a7275..b8a6a5078eae 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -6,6 +6,7 @@ config ARM > select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST > select ARCH_HAVE_CUSTOM_GPIO_H > select ARCH_MIGHT_HAVE_PC_PARPORT > + select ARCH_SUPPORTS_ATOMIC_RMW > select ARCH_USE_BUILTIN_BSWAP > select ARCH_USE_CMPXCHG_LOCKREF > select ARCH_WANT_IPC_PARSE_VERSION > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 5c30b10c0f6c..339dc07f15e2 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -3,6 +3,7 @@ config ARM64 > select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE > select ARCH_USE_CMPXCHG_LOCKREF > select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST > + select ARCH_SUPPORTS_ATOMIC_RMW > select ARCH_WANT_OPTIONAL_GPIOLIB > select ARCH_WANT_COMPAT_IPC_PARSE_VERSION > select ARCH_WANT_FRAME_POINTERS > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index e0998997943b..5bb96f282373 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -145,6 +145,7 @@ config PPC > select HAVE_IRQ_EXIT_ON_IRQ_STACK > select ARCH_USE_CMPXCHG_LOCKREF if PPC64 > select HAVE_ARCH_AUDITSYSCALL > + select ARCH_SUPPORTS_ATOMIC_RMW > > config GENERIC_CSUM > def_bool CPU_LITTLE_ENDIAN > diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig > index 29f2e988c56a..407c87d9879a 100644 > --- a/arch/sparc/Kconfig > +++ b/arch/sparc/Kconfig > @@ -78,6 +78,7 @@ config SPARC64 > select HAVE_C_RECORDMCOUNT > select NO_BOOTMEM > select HAVE_ARCH_AUDITSYSCALL > + select ARCH_SUPPORTS_ATOMIC_RMW Sparc64 does, Sparc32 doesn't, so shouldn't that be select ARCH_SUPPORTS_ATOMIC_RMW if 64BIT ? Other than this, looks good to me (you can add reviewed by or acked by from me to your taste). James -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 2014-06-06 at 10:57 -0700, James Bottomley wrote: > On Fri, 2014-06-06 at 19:53 +0200, Peter Zijlstra wrote: > > On Fri, Jun 06, 2014 at 10:22:21AM -0700, Linus Torvalds wrote: > > > On Fri, Jun 6, 2014 at 10:11 AM, Peter Zijlstra <peterz@infradead.org> wrote: > > > > > > > > +config ARCH_NO_ATOMIC_RMW > > > > + def_bool y > > > > + depends on PARISC || SPARC32 || METAG_ATOMICITY_LOCK1 || (TILE && !TILEGX) || (ARC && !ARC_HAS_LLSC) > > > > > > Ugh. We've had these kinds of things before, and they are broken and > > > nasty to maintain. > > > > > > Just make it > > > > > > config ARCH_SUPPORTS_ATOMIC_RMW > > > bool > > > > > > which defaults to no. And then make MUTEX_SPIN_ON_OWNER depend on that. > > > > --- > > Subject: locking, mutex: Make optimistic spinning depend on ARCH_SUPPORTS_ATOMIC_RMW > > > > The optimistic spin code assumes regular stores and cmpxchg() play nice; > > this is found to not be true for at least: parisc, sparc32, tile32, > > metag-lock1, arc-!llsc and hexagon. > > > > There is further wreckage, but this in particular seemed easy to > > trigger, so blacklist this. > > > > Opt in for known good archs. > > > > Reported-by: Mikulas Patocka <mpatocka@redhat.com> > > Signed-off-by: Peter Zijlstra <peterz@infradead.org> > > --- > > arch/arm/Kconfig | 1 + > > arch/arm64/Kconfig | 1 + > > arch/powerpc/Kconfig | 1 + > > arch/sparc/Kconfig | 1 + > > arch/x86/Kconfig | 1 + > > kernel/Kconfig.locks | 5 ++++- > > 6 files changed, 9 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > > index a2c1a18a7275..b8a6a5078eae 100644 > > --- a/arch/arm/Kconfig > > +++ b/arch/arm/Kconfig > > @@ -6,6 +6,7 @@ config ARM > > select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST > > select ARCH_HAVE_CUSTOM_GPIO_H > > select ARCH_MIGHT_HAVE_PC_PARPORT > > + select ARCH_SUPPORTS_ATOMIC_RMW > > select ARCH_USE_BUILTIN_BSWAP > > select ARCH_USE_CMPXCHG_LOCKREF > > select ARCH_WANT_IPC_PARSE_VERSION > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index 5c30b10c0f6c..339dc07f15e2 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -3,6 +3,7 @@ config ARM64 > > select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE > > select ARCH_USE_CMPXCHG_LOCKREF > > select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST > > + select ARCH_SUPPORTS_ATOMIC_RMW > > select ARCH_WANT_OPTIONAL_GPIOLIB > > select ARCH_WANT_COMPAT_IPC_PARSE_VERSION > > select ARCH_WANT_FRAME_POINTERS > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > > index e0998997943b..5bb96f282373 100644 > > --- a/arch/powerpc/Kconfig > > +++ b/arch/powerpc/Kconfig > > @@ -145,6 +145,7 @@ config PPC > > select HAVE_IRQ_EXIT_ON_IRQ_STACK > > select ARCH_USE_CMPXCHG_LOCKREF if PPC64 > > select HAVE_ARCH_AUDITSYSCALL > > + select ARCH_SUPPORTS_ATOMIC_RMW > > > > config GENERIC_CSUM > > def_bool CPU_LITTLE_ENDIAN > > diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig > > index 29f2e988c56a..407c87d9879a 100644 > > --- a/arch/sparc/Kconfig > > +++ b/arch/sparc/Kconfig > > @@ -78,6 +78,7 @@ config SPARC64 > > select HAVE_C_RECORDMCOUNT > > select NO_BOOTMEM > > select HAVE_ARCH_AUDITSYSCALL > > + select ARCH_SUPPORTS_ATOMIC_RMW > > Sparc64 does, Sparc32 doesn't, so shouldn't that be > > select ARCH_SUPPORTS_ATOMIC_RMW if 64BIT > > ? > > Other than this, looks good to me (you can add reviewed by or acked by > from me to your taste). Oh, wait, I see how sparc does it, never mind ... James -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Jun 06, 2014 at 10:57:07AM -0700, James Bottomley wrote: > > diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig > > index 29f2e988c56a..407c87d9879a 100644 > > --- a/arch/sparc/Kconfig > > +++ b/arch/sparc/Kconfig > > @@ -78,6 +78,7 @@ config SPARC64 ^^^^^^^^^^^^^^ > > select HAVE_C_RECORDMCOUNT > > select NO_BOOTMEM > > select HAVE_ARCH_AUDITSYSCALL > > + select ARCH_SUPPORTS_ATOMIC_RMW > > Sparc64 does, Sparc32 doesn't, so shouldn't that be > > select ARCH_SUPPORTS_ATOMIC_RMW if 64BIT > > ? arch/sparc/Kconfig has 3 large sections: config SPARC (included in both) config SPARC32 (specific to 32bit) config SPARC64 (specific to 64bit) I added it to the last. -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index a2c1a18a7275..b8a6a5078eae 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -6,6 +6,7 @@ config ARM select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAVE_CUSTOM_GPIO_H select ARCH_MIGHT_HAVE_PC_PARPORT + select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF select ARCH_WANT_IPC_PARSE_VERSION diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 5c30b10c0f6c..339dc07f15e2 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -3,6 +3,7 @@ config ARM64 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_USE_CMPXCHG_LOCKREF select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST + select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_WANT_OPTIONAL_GPIOLIB select ARCH_WANT_COMPAT_IPC_PARSE_VERSION select ARCH_WANT_FRAME_POINTERS diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index e0998997943b..5bb96f282373 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -145,6 +145,7 @@ config PPC select HAVE_IRQ_EXIT_ON_IRQ_STACK select ARCH_USE_CMPXCHG_LOCKREF if PPC64 select HAVE_ARCH_AUDITSYSCALL + select ARCH_SUPPORTS_ATOMIC_RMW config GENERIC_CSUM def_bool CPU_LITTLE_ENDIAN diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 29f2e988c56a..407c87d9879a 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -78,6 +78,7 @@ config SPARC64 select HAVE_C_RECORDMCOUNT select NO_BOOTMEM select HAVE_ARCH_AUDITSYSCALL + select ARCH_SUPPORTS_ATOMIC_RMW config ARCH_DEFCONFIG string diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 3d4951d35587..2fe1f7c5994e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -130,6 +130,7 @@ config X86 select HAVE_CC_STACKPROTECTOR select GENERIC_CPU_AUTOPROBE select HAVE_ARCH_AUDITSYSCALL + select ARCH_SUPPORTS_ATOMIC_RMW config INSTRUCTION_DECODER def_bool y diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks index d2b32ac27a39..ecee67a00f5f 100644 --- a/kernel/Kconfig.locks +++ b/kernel/Kconfig.locks @@ -220,6 +220,9 @@ config INLINE_WRITE_UNLOCK_IRQRESTORE endif +config ARCH_SUPPORTS_ATOMIC_RMW + bool + config MUTEX_SPIN_ON_OWNER def_bool y - depends on SMP && !DEBUG_MUTEXES + depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW