Messages in this thread | | | Subject | Re: [PATCH RFC V3 2/2] net: Optimize snmp stat aggregation by walking all the percpu data at once | From | Joe Perches <> | Date | Sat, 29 Aug 2015 08:21:24 -0700 |
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On Sat, 2015-08-29 at 07:32 -0700, Eric Dumazet wrote: > On Sat, 2015-08-29 at 14:37 +0530, Raghavendra K T wrote: > > > > > static inline void __snmp6_fill_stats64(u64 *stats, void __percpu *mib, > > - int items, int bytes, size_t syncpoff) > > + int items, int bytes, size_t syncpoff) > > { > > - int i; > > + int i, c; > > int pad = bytes - sizeof(u64) * items; > > + u64 buff[items]; > > + > > One last comment : using variable length arrays is confusing for the > reader, and sparse as well. > > $ make C=2 net/ipv6/addrconf.o > ... > CHECK net/ipv6/addrconf.c > net/ipv6/addrconf.c:4733:18: warning: Variable length array is used. > net/ipv6/addrconf.c:4737:25: error: cannot size expression > > > I suggest you remove 'items' parameter and replace it by > IPSTATS_MIB_MAX, as __snmp6_fill_stats64() is called exactly once.
If you respin, I suggest:
o remove "items" from the __snmp6_fill_stats64 arguments and use IPSTATS_MIB_MAX in the function instead
o add braces around the for_each_possible_cpu loop
for_each_possible_cpu(c) { for (i = 1; i < items; i++) buff[i] += snmp_get_cpu_field64(mib, c, i, syncpoff); }
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