Re: [PATCH 07/10] x86: uv cleanup

[Cliff Wickman <cpw@sgi.com>]

Hi Tejun,

I appreciate your consolidation and cleanup of the UV code, relative
to 32 vs 64.

I have a question about the addition of the
        WARN_ON(!in_atomic());
in uv_flush_tlb_others().
The patch is
http://marc.info/?l=linux-kernel&m=123252788121855&w=2

I expect this function to always entered preemptable.  
Could you explain a bit about your thought behind this WARN_ON?

Thanks.
-Cliff




const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
                                          struct mm_struct *mm,
                                          unsigned long va, unsigned int cpu)
{
        static DEFINE_PER_CPU(cpumask_t, flush_tlb_mask);
        struct cpumask *flush_mask = &__get_cpu_var(flush_tlb_mask);
        int i;
        int bit;
        int blade;
        int uv_cpu;
        int this_blade;
        int locals = 0;
        struct bau_desc *bau_desc;

        WARN_ON(!in_atomic());

        cpumask_andnot(flush_mask, cpumask, cpumask_of(cpu));

        uv_cpu = uv_blade_processor_id();
        this_blade = uv_numa_blade_id();