Messages in this thread | | | Date | Wed, 17 Nov 2010 00:52:55 -0800 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH 09/14] xen/pvticketlock: Xen implementation for PV ticket locks |
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On 11/17/2010 12:11 AM, Jan Beulich wrote: >>>> On 16.11.10 at 22:08, Jeremy Fitzhardinge <jeremy@goop.org> wrote: >> +static void xen_lock_spinning(struct arch_spinlock *lock, unsigned want) >> { >> - struct xen_spinlock *xl = (struct xen_spinlock *)lock; >> - struct xen_spinlock *prev; >> int irq = __get_cpu_var(lock_kicker_irq); >> - int ret; >> + struct xen_lock_waiting *w = &__get_cpu_var(lock_waiting); >> + int cpu = smp_processor_id(); >> u64 start; >> >> /* If kicker interrupts not initialized yet, just spin */ >> if (irq == -1) >> - return 0; >> + return; >> >> start = spin_time_start(); >> >> - /* announce we're spinning */ >> - prev = spinning_lock(xl); >> + w->want = want; >> + w->lock = lock; >> + >> + /* This uses set_bit, which atomic and therefore a barrier */ >> + cpumask_set_cpu(cpu, &waiting_cpus); > Since you don't allow nesting, don't you need to disable > interrupts before you touch per-CPU state?
Yes, I think you're right - interrupts need to be disabled for the bulk of this function.
J
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