Messages in this thread | | | Subject | Re: [tip:locking/core] x86, locking/rwlocks: Enable qrwlocks on x86 | From | Paul Bolle <> | Date | Wed, 11 Jun 2014 10:14:11 +0200 |
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On Fri, 2014-06-06 at 05:20 -0700, tip-bot for Waiman Long wrote: > Make x86 use the fair rwlock_t. > > Implement the custom queue_write_unlock() for best performance.
This landed in linux-next yesterday (ie, next-20140610).
> Signed-off-by: Waiman Long <Waiman.Long@hp.com> > [peterz: near complete rewrite] > Signed-off-by: Peter Zijlstra <peterz@infradead.org> > Cc: Dave Jones <davej@redhat.com> > Cc: Jeremy Fitzhardinge <jeremy@goop.org> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Oleg Nesterov <oleg@redhat.com> > Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> > Cc: "Paul E.McKenney" <paulmck@linux.vnet.ibm.com> > Cc: linux-kernel@vger.kernel.org > Cc: x86@kernel.org > Link: http://lkml.kernel.org/n/tip-r1xuzmdysvuhl3h86n5fbxi7@git.kernel.org > Signed-off-by: Ingo Molnar <mingo@kernel.org> >[...] > diff --git a/arch/x86/include/asm/qrwlock.h b/arch/x86/include/asm/qrwlock.h > new file mode 100644 > index 0000000..70f46f0 > --- /dev/null > +++ b/arch/x86/include/asm/qrwlock.h > @@ -0,0 +1,17 @@ > +#ifndef _ASM_X86_QRWLOCK_H > +#define _ASM_X86_QRWLOCK_H > + > +#include <asm-generic/qrwlock_types.h> > + > +#if !defined(CONFIG_X86_OOSTORE) && !defined(CONFIG_X86_PPRO_FENCE)
X86_OOSTORE was removed in v3.14, see commit 09df7c4c8097 ("x86: Remove CONFIG_X86_OOSTORE"). So the first test can be removed here, as it will always be true. Should I submit the trivial, but probably untested, patch to do that or do you prefer to do that yourself?
> +#define queue_write_unlock queue_write_unlock > +static inline void queue_write_unlock(struct qrwlock *lock) > +{ > + barrier(); > + ACCESS_ONCE(*(u8 *)&lock->cnts) = 0; > +} > +#endif > + > +#include <asm-generic/qrwlock.h> > + > +#endif /* _ASM_X86_QRWLOCK_H */
Thanks,
Paul Bolle
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