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Message-Id: <20220310004603.543196-1-eric.dumazet@gmail.com>
Date: Wed, 9 Mar 2022 16:46:03 -0800
From: Eric Dumazet <eric.dumazet@...il.com>
To: "David S . Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>
Cc: netdev <netdev@...r.kernel.org>,
Eric Dumazet <edumazet@...gle.com>,
Eric Dumazet <eric.dumazet@...il.com>,
jeffreyji <jeffreyji@...gle.com>,
Brian Vazquez <brianvv@...gle.com>
Subject: [PATCH v2 net-next] net: add per-cpu storage and net->core_stats
From: Eric Dumazet <edumazet@...gle.com>
Before adding yet another possibly contended atomic_long_t,
it is time to add per-cpu storage for existing ones:
dev->tx_dropped, dev->rx_dropped, and dev->rx_nohandler
Because many devices do not have to increment such counters,
allocate the per-cpu storage on demand, so that dev_get_stats()
does not have to spend considerable time folding zero counters.
Note that some drivers have abused these counters which
were supposed to be only used by core networking stack.
v2: add a missing include (reported by kernel test robot <lkp@...el.com>)
Change in netdev_core_stats_alloc() (Jakub)
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: jeffreyji <jeffreyji@...gle.com>
Reviewed-by: Brian Vazquez <brianvv@...gle.com>
Reviewed-by: Jakub Kicinski <kuba@...nel.org>
---
drivers/net/bonding/bond_main.c | 2 +-
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 4 +-
.../net/ethernet/hisilicon/hns/hns_ethtool.c | 4 +-
.../ethernet/qualcomm/rmnet/rmnet_handlers.c | 2 +-
drivers/net/ipvlan/ipvlan_core.c | 2 +-
drivers/net/macvlan.c | 2 +-
drivers/net/net_failover.c | 2 +-
drivers/net/tun.c | 16 +++---
drivers/net/vxlan/vxlan_core.c | 2 +-
include/linux/netdevice.h | 46 +++++++++++++----
include/net/bonding.h | 2 +-
net/core/dev.c | 50 +++++++++++++++----
net/core/gro_cells.c | 2 +-
net/hsr/hsr_device.c | 2 +-
net/xfrm/xfrm_device.c | 2 +-
15 files changed, 100 insertions(+), 40 deletions(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 55e0ba2a163d0d9c17fdaf47a49d7a2190959651..15eddca7b4b6623ccb2b17d1d8f9a092ebd90ff5 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -5120,7 +5120,7 @@ static netdev_tx_t bond_xmit_broadcast(struct sk_buff *skb,
if (xmit_suc)
return NETDEV_TX_OK;
- atomic_long_inc(&bond_dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(bond_dev);
return NET_XMIT_DROP;
}
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 63b8fc4f9d42748985563431f8fef47644018dc0..3af230e5fa3241ae396060fe8a8fae2b0c77a6f5 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -370,7 +370,7 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
i = skb_get_queue_mapping(skb);
if (unlikely(i >= bp->tx_nr_rings)) {
dev_kfree_skb_any(skb);
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
return NETDEV_TX_OK;
}
@@ -646,7 +646,7 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
if (txr->kick_pending)
bnxt_txr_db_kick(bp, txr, txr->tx_prod);
txr->tx_buf_ring[txr->tx_prod].skb = NULL;
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
return NETDEV_TX_OK;
}
diff --git a/drivers/net/ethernet/hisilicon/hns/hns_ethtool.c b/drivers/net/ethernet/hisilicon/hns/hns_ethtool.c
index d7a27c244d48060a7e5efe22376e9f465942a94a..54faf0f2d1d867066b9fc121fc5a3d5e0d296afa 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_ethtool.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_ethtool.c
@@ -887,8 +887,8 @@ static void hns_get_ethtool_stats(struct net_device *netdev,
p[21] = net_stats->rx_compressed;
p[22] = net_stats->tx_compressed;
- p[23] = netdev->rx_dropped.counter;
- p[24] = netdev->tx_dropped.counter;
+ p[23] = 0; /* was netdev->rx_dropped.counter */
+ p[24] = 0; /* was netdev->tx_dropped.counter */
p[25] = priv->tx_timeout_count;
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index bfbd7847f9468d5698e115ec39ea92053978b45f..a313242a762e2e732c5bd5856ea8902f855e56b4 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
@@ -207,7 +207,7 @@ rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb)
dev = skb->dev;
port = rmnet_get_port_rcu(dev);
if (unlikely(!port)) {
- atomic_long_inc(&skb->dev->rx_nohandler);
+ dev_core_stats_rx_nohandler_inc(skb->dev);
kfree_skb(skb);
goto done;
}
diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index c613900c3811f9e0482092f79bad3bf9cfab25b3..6ffb27419e64b36666d395da924304a943343640 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -555,7 +555,7 @@ static void ipvlan_multicast_enqueue(struct ipvl_port *port,
schedule_work(&port->wq);
} else {
spin_unlock(&port->backlog.lock);
- atomic_long_inc(&skb->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(skb->dev);
kfree_skb(skb);
}
}
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 33753a2fde292f8f415eefe957d09be5db1c4d55..4b77819e9328175e664779855cffab4c5352dfe5 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -371,7 +371,7 @@ static void macvlan_broadcast_enqueue(struct macvlan_port *port,
free_nskb:
kfree_skb(nskb);
err:
- atomic_long_inc(&skb->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(skb->dev);
}
static void macvlan_flush_sources(struct macvlan_port *port,
diff --git a/drivers/net/net_failover.c b/drivers/net/net_failover.c
index 86ec5aae42891aa287a3eea3e91db4462990a350..21a0435c02de6c44e5175d0f204c255c0e22ddd5 100644
--- a/drivers/net/net_failover.c
+++ b/drivers/net/net_failover.c
@@ -89,7 +89,7 @@ static int net_failover_close(struct net_device *dev)
static netdev_tx_t net_failover_drop_xmit(struct sk_buff *skb,
struct net_device *dev)
{
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 2b9a22669a12681185c631e772c59994ba47b574..276a0e42ca8eaa85a96b366ab56f5abda3ff7a27 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1135,7 +1135,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
return NETDEV_TX_OK;
drop:
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
skb_tx_error(skb);
kfree_skb_reason(skb, drop_reason);
rcu_read_unlock();
@@ -1291,7 +1291,7 @@ static int tun_xdp_xmit(struct net_device *dev, int n,
void *frame = tun_xdp_to_ptr(xdp);
if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
break;
}
nxmit++;
@@ -1626,7 +1626,7 @@ static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
trace_xdp_exception(tun->dev, xdp_prog, act);
fallthrough;
case XDP_DROP:
- atomic_long_inc(&tun->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(tun->dev);
break;
}
@@ -1797,7 +1797,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
*/
skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
if (IS_ERR(skb)) {
- atomic_long_inc(&tun->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(tun->dev);
return PTR_ERR(skb);
}
if (!skb)
@@ -1826,7 +1826,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
if (IS_ERR(skb)) {
if (PTR_ERR(skb) != -EAGAIN)
- atomic_long_inc(&tun->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(tun->dev);
if (frags)
mutex_unlock(&tfile->napi_mutex);
return PTR_ERR(skb);
@@ -1841,7 +1841,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
err = -EFAULT;
drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
drop:
- atomic_long_inc(&tun->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(tun->dev);
kfree_skb_reason(skb, drop_reason);
if (frags) {
tfile->napi.skb = NULL;
@@ -1876,7 +1876,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
pi.proto = htons(ETH_P_IPV6);
break;
default:
- atomic_long_inc(&tun->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(tun->dev);
kfree_skb(skb);
return -EINVAL;
}
@@ -1956,7 +1956,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
skb_headlen(skb));
if (unlikely(headlen > skb_headlen(skb))) {
- atomic_long_inc(&tun->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(tun->dev);
napi_free_frags(&tfile->napi);
rcu_read_unlock();
mutex_unlock(&tfile->napi_mutex);
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index e440cdd4f710e5f6a8e583b1a5acea61ad44314a..d1fec21d39626d06dff0357f774c88d5bb76ea8c 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -1760,7 +1760,7 @@ static int vxlan_rcv(struct sock *sk, struct sk_buff *skb)
if (unlikely(!(vxlan->dev->flags & IFF_UP))) {
rcu_read_unlock();
- atomic_long_inc(&vxlan->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(vxlan->dev);
vxlan_vnifilter_count(vxlan, vni, vninode,
VXLAN_VNI_STATS_RX_DROPS, 0);
goto drop;
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 29a850a8d4604bb2ac43b582595f301aaa96a0bc..748395430b06b41bbad06edd726649b76e08f676 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -28,6 +28,7 @@
#include <linux/prefetch.h>
#include <asm/cache.h>
#include <asm/byteorder.h>
+#include <asm/local.h>
#include <linux/percpu.h>
#include <linux/rculist.h>
@@ -194,6 +195,14 @@ struct net_device_stats {
unsigned long tx_compressed;
};
+/* per-cpu stats, allocated on demand.
+ * Try to fit them in a single cache line, for dev_get_stats() sake.
+ */
+struct net_device_core_stats {
+ local_t rx_dropped;
+ local_t tx_dropped;
+ local_t rx_nohandler;
+} __aligned(4 * sizeof(local_t));
#include <linux/cache.h>
#include <linux/skbuff.h>
@@ -1735,12 +1744,8 @@ enum netdev_ml_priv_type {
* @stats: Statistics struct, which was left as a legacy, use
* rtnl_link_stats64 instead
*
- * @rx_dropped: Dropped packets by core network,
+ * @core_stats: core networking counters,
* do not use this in drivers
- * @tx_dropped: Dropped packets by core network,
- * do not use this in drivers
- * @rx_nohandler: nohandler dropped packets by core network on
- * inactive devices, do not use this in drivers
* @carrier_up_count: Number of times the carrier has been up
* @carrier_down_count: Number of times the carrier has been down
*
@@ -2023,9 +2028,7 @@ struct net_device {
struct net_device_stats stats; /* not used by modern drivers */
- atomic_long_t rx_dropped;
- atomic_long_t tx_dropped;
- atomic_long_t rx_nohandler;
+ struct net_device_core_stats __percpu *core_stats;
/* Stats to monitor link on/off, flapping */
atomic_t carrier_up_count;
@@ -3839,13 +3842,38 @@ static __always_inline bool __is_skb_forwardable(const struct net_device *dev,
return false;
}
+struct net_device_core_stats *netdev_core_stats_alloc(struct net_device *dev);
+
+static inline struct net_device_core_stats *dev_core_stats(struct net_device *dev)
+{
+ /* This READ_ONCE() pairs with the write in netdev_core_stats_alloc() */
+ struct net_device_core_stats __percpu *p = READ_ONCE(dev->core_stats);
+
+ if (likely(p))
+ return this_cpu_ptr(p);
+
+ return netdev_core_stats_alloc(dev);
+}
+
+#define DEV_CORE_STATS_INC(FIELD) \
+static inline void dev_core_stats_##FIELD##_inc(struct net_device *dev) \
+{ \
+ struct net_device_core_stats *p = dev_core_stats(dev); \
+ \
+ if (p) \
+ local_inc(&p->FIELD); \
+}
+DEV_CORE_STATS_INC(rx_dropped)
+DEV_CORE_STATS_INC(tx_dropped)
+DEV_CORE_STATS_INC(rx_nohandler)
+
static __always_inline int ____dev_forward_skb(struct net_device *dev,
struct sk_buff *skb,
const bool check_mtu)
{
if (skb_orphan_frags(skb, GFP_ATOMIC) ||
unlikely(!__is_skb_forwardable(dev, skb, check_mtu))) {
- atomic_long_inc(&dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(dev);
kfree_skb(skb);
return NET_RX_DROP;
}
diff --git a/include/net/bonding.h b/include/net/bonding.h
index d0dfe727e0b1cb45b60c6e38af545c083734db12..b14f4c0b4e9ed1c6a94cd03258d935727c971b77 100644
--- a/include/net/bonding.h
+++ b/include/net/bonding.h
@@ -770,7 +770,7 @@ extern const struct sysfs_ops slave_sysfs_ops;
static inline netdev_tx_t bond_tx_drop(struct net_device *dev, struct sk_buff *skb)
{
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
dev_kfree_skb_any(skb);
return NET_XMIT_DROP;
}
diff --git a/net/core/dev.c b/net/core/dev.c
index ba69ddf85af6b4543caa91f314caf54794a3a02a..ccd7eea84e09b25edb1e5a06521a20f394aa5516 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3635,7 +3635,7 @@ static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device
out_kfree_skb:
kfree_skb(skb);
out_null:
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
return NULL;
}
@@ -4186,7 +4186,7 @@ static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
rc = -ENETDOWN;
rcu_read_unlock_bh();
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
kfree_skb_list(skb);
return rc;
out:
@@ -4238,7 +4238,7 @@ int __dev_direct_xmit(struct sk_buff *skb, u16 queue_id)
local_bh_enable();
return ret;
drop:
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
kfree_skb_list(skb);
return NET_XMIT_DROP;
}
@@ -4604,7 +4604,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
sd->dropped++;
rps_unlock_irq_restore(sd, &flags);
- atomic_long_inc(&skb->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(skb->dev);
kfree_skb_reason(skb, reason);
return NET_RX_DROP;
}
@@ -5359,10 +5359,10 @@ static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc,
} else {
drop:
if (!deliver_exact) {
- atomic_long_inc(&skb->dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(skb->dev);
kfree_skb_reason(skb, SKB_DROP_REASON_PTYPE_ABSENT);
} else {
- atomic_long_inc(&skb->dev->rx_nohandler);
+ dev_core_stats_rx_nohandler_inc(skb->dev);
kfree_skb(skb);
}
/* Jamal, now you will not able to escape explaining
@@ -10282,6 +10282,24 @@ void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
}
EXPORT_SYMBOL(netdev_stats_to_stats64);
+struct net_device_core_stats *netdev_core_stats_alloc(struct net_device *dev)
+{
+ struct net_device_core_stats __percpu *p;
+
+ p = alloc_percpu_gfp(struct net_device_core_stats,
+ GFP_ATOMIC | __GFP_NOWARN);
+
+ if (p && cmpxchg(&dev->core_stats, NULL, p))
+ free_percpu(p);
+
+ p = dev->core_stats;
+ if (!p)
+ return NULL;
+
+ return this_cpu_ptr(p);
+}
+EXPORT_SYMBOL(netdev_core_stats_alloc);
+
/**
* dev_get_stats - get network device statistics
* @dev: device to get statistics from
@@ -10296,6 +10314,7 @@ struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
struct rtnl_link_stats64 *storage)
{
const struct net_device_ops *ops = dev->netdev_ops;
+ const struct net_device_core_stats __percpu *p;
if (ops->ndo_get_stats64) {
memset(storage, 0, sizeof(*storage));
@@ -10305,9 +10324,20 @@ struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
} else {
netdev_stats_to_stats64(storage, &dev->stats);
}
- storage->rx_dropped += (unsigned long)atomic_long_read(&dev->rx_dropped);
- storage->tx_dropped += (unsigned long)atomic_long_read(&dev->tx_dropped);
- storage->rx_nohandler += (unsigned long)atomic_long_read(&dev->rx_nohandler);
+
+ /* This READ_ONCE() pairs with the write in netdev_core_stats_alloc() */
+ p = READ_ONCE(dev->core_stats);
+ if (p) {
+ const struct net_device_core_stats *core_stats;
+ int i;
+
+ for_each_possible_cpu(i) {
+ core_stats = per_cpu(p, i);
+ storage->rx_dropped += local_read(&core_stats->rx_dropped);
+ storage->tx_dropped += local_read(&core_stats->tx_dropped);
+ storage->rx_nohandler += local_read(&core_stats->rx_nohandler);
+ }
+ }
return storage;
}
EXPORT_SYMBOL(dev_get_stats);
@@ -10569,6 +10599,8 @@ void free_netdev(struct net_device *dev)
free_percpu(dev->pcpu_refcnt);
dev->pcpu_refcnt = NULL;
#endif
+ free_percpu(dev->core_stats);
+ dev->core_stats = NULL;
free_percpu(dev->xdp_bulkq);
dev->xdp_bulkq = NULL;
diff --git a/net/core/gro_cells.c b/net/core/gro_cells.c
index 8462f926ab457322a12510a4d294ecca617948f0..541c7a72a28a4b00e7e196eca01df42842ea103f 100644
--- a/net/core/gro_cells.c
+++ b/net/core/gro_cells.c
@@ -28,7 +28,7 @@ int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
drop:
- atomic_long_inc(&dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(dev);
kfree_skb(skb);
res = NET_RX_DROP;
goto unlock;
diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index 7f250216433d32dd6fda52d2932e45cedf3fc24d..6ffef47e9be55c408c8c2b32472466205c690507 100644
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -221,7 +221,7 @@ static netdev_tx_t hsr_dev_xmit(struct sk_buff *skb, struct net_device *dev)
skb_reset_mac_len(skb);
hsr_forward_skb(skb, master);
} else {
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
dev_kfree_skb_any(skb);
}
return NETDEV_TX_OK;
diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 39bce5d764de5d28682368e4cbfa18f7c7f16e63..3e3448ada1bb1396e39a119cdbdf3edb9a11ae6f 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -143,7 +143,7 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur
segs = skb_gso_segment(skb, esp_features);
if (IS_ERR(segs)) {
kfree_skb(skb);
- atomic_long_inc(&dev->tx_dropped);
+ dev_core_stats_tx_dropped_inc(dev);
return NULL;
} else {
consume_skb(skb);
--
2.35.1.616.g0bdcbb4464-goog
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