Messages in this thread | | | Subject | Re: [PATCH v2] hv_netvsc: Add per-cpu ethtool stats for netvsc | From | Eric Dumazet <> | Date | Wed, 13 Jun 2018 13:57:33 -0700 |
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On 06/13/2018 12:36 PM, Yidong Ren wrote: > From: Yidong Ren <yidren@microsoft.com> > > This patch implements following ethtool stats fields for netvsc: > cpu<n>_tx/rx_packets/bytes > cpu<n>_vf_tx/rx_packets/bytes
... > > + pcpu_sum = alloc_percpu(struct netvsc_ethtool_pcpu_stats); > + netvsc_get_pcpu_stats(dev, pcpu_sum); > + for_each_present_cpu(cpu) { > + struct netvsc_ethtool_pcpu_stats *this_sum = > + per_cpu_ptr(pcpu_sum, cpu); > + for (j = 0; j < ARRAY_SIZE(pcpu_stats); j++) > + data[i++] = *(u64 *)((void *)this_sum > + + pcpu_stats[j].offset); > + } > + free_percpu(pcpu_sum); >
Using alloc_percpu() / free_percpu() for a short section of code makes no sense.
You actually want to allocate memory local to this cpu, possibly in one chunk, not spread all over the places.
kvmalloc(nr_cpu_ids * sizeof(struct netvsc_ethtool_pcpu_stats)) should be really better, since it would most of the time be satisfied by a single kmalloc()
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