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authorEric Dumazet <eric.dumazet@gmail.com>2011-11-13 01:24:04 +0000
committerDavid S. Miller <davem@davemloft.net>2011-11-14 00:12:26 -0500
commit2a24444f8f2bea694003e3eac5c2f8d9a386bdc5 (patch)
treeef283db22c931c518ac6c0b8bca2e23dd62a7736
parent3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 (diff)
ipv6: reduce percpu needs for icmpv6msg mibs
Reading /proc/net/snmp6 on a machine with a lot of cpus is very expensive (can be ~88000 us). This is because ICMPV6MSG MIB uses 4096 bytes per cpu, and folding values for all possible cpus can read 16 Mbytes of memory (32MBytes on non x86 arches) 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 <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/ipv6.h15
-rw-r--r--include/net/netns/mib.h2
-rw-r--r--include/net/snmp.h2
-rw-r--r--net/ipv6/af_inet6.c8
-rw-r--r--net/ipv6/proc.c15
5 files changed, 23 insertions, 19 deletions
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index a366a8a1fe23..3f0258d2ef01 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -132,6 +132,15 @@ extern struct ctl_path net_ipv6_ctl_path[];
SNMP_INC_STATS##modifier((net)->mib.statname##_statistics, (field));\
})
+/* per device and per net counters are atomic_long_t */
+#define _DEVINC_ATOMIC_ATOMIC(net, statname, idev, field) \
+({ \
+ struct inet6_dev *_idev = (idev); \
+ if (likely(_idev != NULL)) \
+ SNMP_INC_STATS_ATOMIC_LONG((_idev)->stats.statname##dev, (field)); \
+ SNMP_INC_STATS_ATOMIC_LONG((net)->mib.statname##_statistics, (field));\
+})
+
#define _DEVADD(net, statname, modifier, idev, field, val) \
({ \
struct inet6_dev *_idev = (idev); \
@@ -168,11 +177,11 @@ extern struct ctl_path net_ipv6_ctl_path[];
_DEVINCATOMIC(net, icmpv6, _BH, idev, field)
#define ICMP6MSGOUT_INC_STATS(net, idev, field) \
- _DEVINCATOMIC(net, icmpv6msg, , idev, field +256)
+ _DEVINC_ATOMIC_ATOMIC(net, icmpv6msg, idev, field +256)
#define ICMP6MSGOUT_INC_STATS_BH(net, idev, field) \
- _DEVINCATOMIC(net, icmpv6msg, _BH, idev, field +256)
+ _DEVINC_ATOMIC_ATOMIC(net, icmpv6msg, idev, field +256)
#define ICMP6MSGIN_INC_STATS_BH(net, idev, field) \
- _DEVINCATOMIC(net, icmpv6msg, _BH, idev, field)
+ _DEVINC_ATOMIC_ATOMIC(net, icmpv6msg, idev, field)
struct ip6_ra_chain {
struct ip6_ra_chain *next;
diff --git a/include/net/netns/mib.h b/include/net/netns/mib.h
index f360135cb69f..30f6728ee98c 100644
--- a/include/net/netns/mib.h
+++ b/include/net/netns/mib.h
@@ -18,7 +18,7 @@ struct netns_mib {
DEFINE_SNMP_STAT(struct udp_mib, udplite_stats_in6);
DEFINE_SNMP_STAT(struct ipstats_mib, ipv6_statistics);
DEFINE_SNMP_STAT(struct icmpv6_mib, icmpv6_statistics);
- DEFINE_SNMP_STAT(struct icmpv6msg_mib, icmpv6msg_statistics);
+ DEFINE_SNMP_STAT_ATOMIC(struct icmpv6msg_mib, icmpv6msg_statistics);
#endif
#ifdef CONFIG_XFRM_STATISTICS
DEFINE_SNMP_STAT(struct linux_xfrm_mib, xfrm_statistics);
diff --git a/include/net/snmp.h b/include/net/snmp.h
index 0feafa68da01..2f65e1686fc8 100644
--- a/include/net/snmp.h
+++ b/include/net/snmp.h
@@ -84,7 +84,7 @@ struct icmpv6_mib_device {
#define ICMP6MSG_MIB_MAX __ICMP6MSG_MIB_MAX
/* per network ns counters */
struct icmpv6msg_mib {
- unsigned long mibs[ICMP6MSG_MIB_MAX];
+ atomic_long_t mibs[ICMP6MSG_MIB_MAX];
};
/* per device counters, (shared on all cpus) */
struct icmpv6msg_mib_device {
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 1040424c788f..282dc7a91f32 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -985,9 +985,9 @@ static int __net_init ipv6_init_mibs(struct net *net)
sizeof(struct icmpv6_mib),
__alignof__(struct icmpv6_mib)) < 0)
goto err_icmp_mib;
- if (snmp_mib_init((void __percpu **)net->mib.icmpv6msg_statistics,
- sizeof(struct icmpv6msg_mib),
- __alignof__(struct icmpv6msg_mib)) < 0)
+ net->mib.icmpv6msg_statistics = kzalloc(sizeof(struct icmpv6msg_mib),
+ GFP_KERNEL);
+ if (!net->mib.icmpv6msg_statistics)
goto err_icmpmsg_mib;
return 0;
@@ -1008,7 +1008,7 @@ static void ipv6_cleanup_mibs(struct net *net)
snmp_mib_free((void __percpu **)net->mib.udplite_stats_in6);
snmp_mib_free((void __percpu **)net->mib.ipv6_statistics);
snmp_mib_free((void __percpu **)net->mib.icmpv6_statistics);
- snmp_mib_free((void __percpu **)net->mib.icmpv6msg_statistics);
+ kfree(net->mib.icmpv6msg_statistics);
}
static int __net_init inet6_net_init(struct net *net)
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index 1008ce94bc33..fdeb6d03da81 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -142,11 +142,7 @@ static const struct snmp_mib snmp6_udplite6_list[] = {
SNMP_MIB_SENTINEL
};
-/* can be called either with percpu mib (pcpumib != NULL),
- * or shared one (smib != NULL)
- */
-static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, void __percpu **pcpumib,
- atomic_long_t *smib)
+static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, atomic_long_t *smib)
{
char name[32];
int i;
@@ -163,14 +159,14 @@ static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, void __percpu **pcpum
snprintf(name, sizeof(name), "Icmp6%s%s",
i & 0x100 ? "Out" : "In", p);
seq_printf(seq, "%-32s\t%lu\n", name,
- pcpumib ? snmp_fold_field(pcpumib, i) : atomic_long_read(smib + i));
+ atomic_long_read(smib + i));
}
/* print by number (nonzero only) - ICMPMsgStat format */
for (i = 0; i < ICMP6MSG_MIB_MAX; i++) {
unsigned long val;
- val = pcpumib ? snmp_fold_field(pcpumib, i) : atomic_long_read(smib + i);
+ val = atomic_long_read(smib + i);
if (!val)
continue;
snprintf(name, sizeof(name), "Icmp6%sType%u",
@@ -215,8 +211,7 @@ static int snmp6_seq_show(struct seq_file *seq, void *v)
snmp6_ipstats_list, offsetof(struct ipstats_mib, syncp));
snmp6_seq_show_item(seq, (void __percpu **)net->mib.icmpv6_statistics,
NULL, snmp6_icmp6_list);
- snmp6_seq_show_icmpv6msg(seq,
- (void __percpu **)net->mib.icmpv6msg_statistics, NULL);
+ snmp6_seq_show_icmpv6msg(seq, net->mib.icmpv6msg_statistics->mibs);
snmp6_seq_show_item(seq, (void __percpu **)net->mib.udp_stats_in6,
NULL, snmp6_udp6_list);
snmp6_seq_show_item(seq, (void __percpu **)net->mib.udplite_stats_in6,
@@ -246,7 +241,7 @@ static int snmp6_dev_seq_show(struct seq_file *seq, void *v)
snmp6_ipstats_list);
snmp6_seq_show_item(seq, NULL, idev->stats.icmpv6dev->mibs,
snmp6_icmp6_list);
- snmp6_seq_show_icmpv6msg(seq, NULL, idev->stats.icmpv6msgdev->mibs);
+ snmp6_seq_show_icmpv6msg(seq, idev->stats.icmpv6msgdev->mibs);
return 0;
}