Messages in this thread | | | Date | Fri, 03 Feb 2012 11:36:27 -0800 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH] x86: eliminate TICKET_MASK |
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On 02/03/2012 07:06 AM, Jan Beulich wrote: > The definition of it being questionable already (unnecessarily > including a cast), and it being used in a single place that can be > written shorter without it, remove this #define. > > Along the same lines, simplify __ticket_spin_is_locked()'s main > expression, which was the more convoluted way because of needs that > went away with the recent type changes by Jeremy. > > This is pure cleanup, no functional change intended.
That looks reasonable to me.
> Signed-off-by: Jan Beulich <jbeulich@suse.com> > Cc: Jeremy Fitzhardinge <jeremy@goop.org> > > --- > arch/x86/include/asm/spinlock.h | 4 ++-- > arch/x86/include/asm/spinlock_types.h | 1 - > 2 files changed, 2 insertions(+), 3 deletions(-) > > --- 3.3-rc2/arch/x86/include/asm/spinlock.h > +++ 3.3-rc2-x86-ticket-mask/arch/x86/include/asm/spinlock.h > @@ -88,14 +88,14 @@ static inline int __ticket_spin_is_locke > { > struct __raw_tickets tmp = ACCESS_ONCE(lock->tickets); > > - return !!(tmp.tail ^ tmp.head); > + return tmp.tail != tmp.head; > } > > static inline int __ticket_spin_is_contended(arch_spinlock_t *lock) > { > struct __raw_tickets tmp = ACCESS_ONCE(lock->tickets); > > - return ((tmp.tail - tmp.head) & TICKET_MASK) > 1; > + return (__ticket_t)(tmp.tail - tmp.head) > 1; > }
Yes. I only left these unchanged the first time around because I didn't want to inadvertently change them, but my intent was to make them more straightforward like this.
> > #ifndef CONFIG_PARAVIRT_SPINLOCKS > --- 3.3-rc2/arch/x86/include/asm/spinlock_types.h > +++ 3.3-rc2-x86-ticket-mask/arch/x86/include/asm/spinlock_types.h > @@ -16,7 +16,6 @@ typedef u32 __ticketpair_t; > #endif > > #define TICKET_SHIFT (sizeof(__ticket_t) * 8) > -#define TICKET_MASK ((__ticket_t)((1 << TICKET_SHIFT) - 1)) > > typedef struct arch_spinlock { > union { > > >
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Thanks, J
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