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

From: Cliff Wickman
Date: Tue Jan 27 2009 - 19:18:13 EST




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();

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