Messages in this thread | | | Date | Sat, 29 Aug 2015 22:55:40 +0530 | From | Raghavendra K T <> | Subject | Re: [PATCH RFC V3 2/2] net: Optimize snmp stat aggregation by walking all the percpu data at once |
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On 08/29/2015 08:51 PM, Joe Perches wrote: > 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
Yes, as also suggested by Eric.
> 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); > } >
Sure. It makes it more readable. will respin V4 with these changes (+ memset 0 for pad which I realized).
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