From acb32ba3dee66d58704caeeb8c6ff95f60efdc66 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 8 Nov 2011 13:04:43 +0000 Subject: ipv4: reduce percpu needs for icmpmsg mibs Reading /proc/net/snmp on a machine with a lot of cpus is very expensive (can be ~88000 us). This is because ICMPMSG MIB uses 4096 bytes per cpu, and folding values for all possible cpus can read 16 Mbytes of memory. ICMP messages are not considered as fast path on a typical server, and eventually few cpus handle them anyway. We can afford an atomic operation instead of using percpu data. This saves 4096 bytes per cpu and per network namespace. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/snmp.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/net/snmp.h') diff --git a/include/net/snmp.h b/include/net/snmp.h index 8f0f9ac0307f..0feafa68da01 100644 --- a/include/net/snmp.h +++ b/include/net/snmp.h @@ -67,7 +67,7 @@ struct icmp_mib { #define ICMPMSG_MIB_MAX __ICMPMSG_MIB_MAX struct icmpmsg_mib { - unsigned long mibs[ICMPMSG_MIB_MAX]; + atomic_long_t mibs[ICMPMSG_MIB_MAX]; }; /* ICMP6 (IPv6-ICMP) */ -- cgit v1.2.3