Commit 94b601bc authored by Jeremy Kerr's avatar Jeremy Kerr Committed by Jakub Kicinski
Browse files

net: core: Implement dstats-type stats collections 



We currently have dev_get_tstats64() for collecting per-cpu stats of
type pcpu_sw_netstats ("tstats"). However, tstats doesn't allow for
accounting tx/rx drops. We do have a stats variant that does have stats
for dropped packets: struct pcpu_dstats, but there are no core helpers
for using those stats.

The VRF driver uses dstats, by providing its own collation/fetch
functions to do so.

This change adds a common implementation for dstats-type collection,
used when pcpu_stat_type == NETDEV_PCPU_STAT_DSTAT. This is based on the
VRF driver's existing stats collator (plus the unused tx_drops stat from
there). We will switch the VRF driver to use this in the next change.

Signed-off-by: default avatarJeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240607-dstats-v3-2-cc781fe116f7@codeconstruct.com.au


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent fa59dc2f

net/core/dev.c

+50 −0
Original line number Diff line number Diff line
@@ -10703,6 +10703,54 @@ void netdev_run_todo(void) 
		wake_up(&netdev_unregistering_wq);

}



/* Collate per-cpu network dstats statistics

 *

 * Read per-cpu network statistics from dev->dstats and populate the related

 * fields in @s.

 */

static void dev_fetch_dstats(struct rtnl_link_stats64 *s,

			     const struct pcpu_dstats __percpu *dstats)

{

	int cpu;



	for_each_possible_cpu(cpu) {

		u64 rx_packets, rx_bytes, rx_drops;

		u64 tx_packets, tx_bytes, tx_drops;

		const struct pcpu_dstats *stats;

		unsigned int start;



		stats = per_cpu_ptr(dstats, cpu);

		do {

			start = u64_stats_fetch_begin(&stats->syncp);

			rx_packets = u64_stats_read(&stats->rx_packets);

			rx_bytes   = u64_stats_read(&stats->rx_bytes);

			rx_drops   = u64_stats_read(&stats->rx_drops);

			tx_packets = u64_stats_read(&stats->tx_packets);

			tx_bytes   = u64_stats_read(&stats->tx_bytes);

			tx_drops   = u64_stats_read(&stats->tx_drops);

		} while (u64_stats_fetch_retry(&stats->syncp, start));



		s->rx_packets += rx_packets;

		s->rx_bytes   += rx_bytes;

		s->rx_dropped += rx_drops;

		s->tx_packets += tx_packets;

		s->tx_bytes   += tx_bytes;

		s->tx_dropped += tx_drops;

	}

}



/* ndo_get_stats64 implementation for dtstats-based accounting.

 *

 * Populate @s from dev->stats and dev->dstats. This is used internally by the

 * core for NETDEV_PCPU_STAT_DSTAT-type stats collection.

 */

static void dev_get_dstats64(const struct net_device *dev,

			     struct rtnl_link_stats64 *s)

{

	netdev_stats_to_stats64(s, &dev->stats);

	dev_fetch_dstats(s, dev->dstats);

}



/* Convert net_device_stats to rtnl_link_stats64. rtnl_link_stats64 has

 * all the same fields in the same order as net_device_stats, with only

 * the type differing, but rtnl_link_stats64 may have additional fields
@@ -10779,6 +10827,8 @@ struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev, 
		netdev_stats_to_stats64(storage, ops->ndo_get_stats(dev));

	} else if (dev->pcpu_stat_type == NETDEV_PCPU_STAT_TSTATS) {

		dev_get_tstats64(dev, storage);

	} else if (dev->pcpu_stat_type == NETDEV_PCPU_STAT_DSTATS) {

		dev_get_dstats64(dev, storage);

	} else {

		netdev_stats_to_stats64(storage, &dev->stats);

	}