net: reorganize IP MIB values

Reduce IP latencies by placing hot MIB IP fields in a single cache line.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/snmp.h b/include/linux/snmp.h
index 00bc189..ad6e3a6 100644 (file)
--- a/include/linux/snmp.h
+++ b/include/linux/snmp.h
@@ -18,7 +18,14 @@
 enum
 {
        IPSTATS_MIB_NUM = 0,
+/* frequently written fields in fast path, kept in same cache line */
        IPSTATS_MIB_INPKTS,                     /* InReceives */
+       IPSTATS_MIB_INOCTETS,                   /* InOctets */
+       IPSTATS_MIB_INDELIVERS,                 /* InDelivers */
+       IPSTATS_MIB_OUTFORWDATAGRAMS,           /* OutForwDatagrams */
+       IPSTATS_MIB_OUTPKTS,                    /* OutRequests */
+       IPSTATS_MIB_OUTOCTETS,                  /* OutOctets */
+/* other fields */
        IPSTATS_MIB_INHDRERRORS,                /* InHdrErrors */
        IPSTATS_MIB_INTOOBIGERRORS,             /* InTooBigErrors */
        IPSTATS_MIB_INNOROUTES,                 /* InNoRoutes */
@@ -26,9 +33,6 @@ enum
        IPSTATS_MIB_INUNKNOWNPROTOS,            /* InUnknownProtos */
        IPSTATS_MIB_INTRUNCATEDPKTS,            /* InTruncatedPkts */
        IPSTATS_MIB_INDISCARDS,                 /* InDiscards */
-       IPSTATS_MIB_INDELIVERS,                 /* InDelivers */
-       IPSTATS_MIB_OUTFORWDATAGRAMS,           /* OutForwDatagrams */
-       IPSTATS_MIB_OUTPKTS,                    /* OutRequests */
        IPSTATS_MIB_OUTDISCARDS,                /* OutDiscards */
        IPSTATS_MIB_OUTNOROUTES,                /* OutNoRoutes */
        IPSTATS_MIB_REASMTIMEOUT,               /* ReasmTimeout */
@@ -42,8 +46,6 @@ enum
        IPSTATS_MIB_OUTMCASTPKTS,               /* OutMcastPkts */
        IPSTATS_MIB_INBCASTPKTS,                /* InBcastPkts */
        IPSTATS_MIB_OUTBCASTPKTS,               /* OutBcastPkts */
-       IPSTATS_MIB_INOCTETS,                   /* InOctets */
-       IPSTATS_MIB_OUTOCTETS,                  /* OutOctets */
        IPSTATS_MIB_INMCASTOCTETS,              /* InMcastOctets */
        IPSTATS_MIB_OUTMCASTOCTETS,             /* OutMcastOctets */
        IPSTATS_MIB_INBCASTOCTETS,              /* InBcastOctets */