47 lines
969 B
C
47 lines
969 B
C
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/*
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* Fast batching percpu counters.
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*/
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#include <linux/percpu_counter.h>
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#include <linux/module.h>
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void percpu_counter_mod(struct percpu_counter *fbc, long amount)
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{
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long count;
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long *pcount;
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int cpu = get_cpu();
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pcount = per_cpu_ptr(fbc->counters, cpu);
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count = *pcount + amount;
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if (count >= FBC_BATCH || count <= -FBC_BATCH) {
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spin_lock(&fbc->lock);
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fbc->count += count;
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*pcount = 0;
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spin_unlock(&fbc->lock);
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} else {
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*pcount = count;
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}
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put_cpu();
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}
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EXPORT_SYMBOL(percpu_counter_mod);
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/*
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* Add up all the per-cpu counts, return the result. This is a more accurate
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* but much slower version of percpu_counter_read_positive()
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*/
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long percpu_counter_sum(struct percpu_counter *fbc)
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{
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long ret;
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int cpu;
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spin_lock(&fbc->lock);
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ret = fbc->count;
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for_each_possible_cpu(cpu) {
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long *pcount = per_cpu_ptr(fbc->counters, cpu);
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ret += *pcount;
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}
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spin_unlock(&fbc->lock);
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return ret < 0 ? 0 : ret;
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}
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EXPORT_SYMBOL(percpu_counter_sum);
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