net, neigh: introduce interval_probe_time_ms for periodic probe

commit ed6cd6a17896 ("net, neigh: Set lower cap for neigh_managed_work rearming")
fixed a case when DELAY_PROBE_TIME is configured to 0, the processing of the
system work queue hog CPU to 100%, and further more we should introduce
a new option used by periodic probe

Signed-off-by: Yuwei Wang <[e-mail]>
Signed-off-by: Paolo Abeni <[e-mail]>

Documentation/networking/ip-sysctl.rst

···
 
 	Default: 101
 
+neigh/default/interval_probe_time_ms - INTEGER
+	The probe interval for neighbor entries with NTF_MANAGED flag,
+	the min value is 1.
+
+	Default: 5000
+
 mtu_expires - INTEGER
 	Time, in seconds, that cached PMTU information is kept.
 

include/net/neighbour.h

···
 	NEIGH_VAR_RETRANS_TIME,
 	NEIGH_VAR_BASE_REACHABLE_TIME,
 	NEIGH_VAR_DELAY_PROBE_TIME,
+	NEIGH_VAR_INTERVAL_PROBE_TIME_MS,
 	NEIGH_VAR_GC_STALETIME,
 	NEIGH_VAR_QUEUE_LEN_BYTES,
 	NEIGH_VAR_PROXY_QLEN,

include/uapi/linux/neighbour.h

···
 	NDTPA_QUEUE_LENBYTES,		/* u32 */
 	NDTPA_MCAST_REPROBES,		/* u32 */
 	NDTPA_PAD,
+	NDTPA_INTERVAL_PROBE_TIME_MS,	/* u64, msecs */
 	__NDTPA_MAX
 };
 #define NDTPA_MAX (__NDTPA_MAX - 1)

include/uapi/linux/sysctl.h

···
 
 /* /proc/sys/net/<protocol>/neigh/<dev> */
 enum {
-	NET_NEIGH_MCAST_SOLICIT=1,
-	NET_NEIGH_UCAST_SOLICIT=2,
-	NET_NEIGH_APP_SOLICIT=3,
-	NET_NEIGH_RETRANS_TIME=4,
-	NET_NEIGH_REACHABLE_TIME=5,
-	NET_NEIGH_DELAY_PROBE_TIME=6,
-	NET_NEIGH_GC_STALE_TIME=7,
-	NET_NEIGH_UNRES_QLEN=8,
-	NET_NEIGH_PROXY_QLEN=9,
-	NET_NEIGH_ANYCAST_DELAY=10,
-	NET_NEIGH_PROXY_DELAY=11,
-	NET_NEIGH_LOCKTIME=12,
-	NET_NEIGH_GC_INTERVAL=13,
-	NET_NEIGH_GC_THRESH1=14,
-	NET_NEIGH_GC_THRESH2=15,
-	NET_NEIGH_GC_THRESH3=16,
-	NET_NEIGH_RETRANS_TIME_MS=17,
-	NET_NEIGH_REACHABLE_TIME_MS=18,
+	NET_NEIGH_MCAST_SOLICIT = 1,
+	NET_NEIGH_UCAST_SOLICIT = 2,
+	NET_NEIGH_APP_SOLICIT = 3,
+	NET_NEIGH_RETRANS_TIME = 4,
+	NET_NEIGH_REACHABLE_TIME = 5,
+	NET_NEIGH_DELAY_PROBE_TIME = 6,
+	NET_NEIGH_GC_STALE_TIME = 7,
+	NET_NEIGH_UNRES_QLEN = 8,
+	NET_NEIGH_PROXY_QLEN = 9,
+	NET_NEIGH_ANYCAST_DELAY = 10,
+	NET_NEIGH_PROXY_DELAY = 11,
+	NET_NEIGH_LOCKTIME = 12,
+	NET_NEIGH_GC_INTERVAL = 13,
+	NET_NEIGH_GC_THRESH1 = 14,
+	NET_NEIGH_GC_THRESH2 = 15,
+	NET_NEIGH_GC_THRESH3 = 16,
+	NET_NEIGH_RETRANS_TIME_MS = 17,
+	NET_NEIGH_REACHABLE_TIME_MS = 18,
+	NET_NEIGH_INTERVAL_PROBE_TIME_MS = 19,
 };
 
 /* /proc/sys/net/dccp */

net/core/neighbour.c

···
 	list_for_each_entry(neigh, &tbl->managed_list, managed_list)
 		neigh_event_send_probe(neigh, NULL, false);
 	queue_delayed_work(system_power_efficient_wq, &tbl->managed_work,
-			   max(NEIGH_VAR(&tbl->parms, DELAY_PROBE_TIME), HZ));
+			   NEIGH_VAR(&tbl->parms, INTERVAL_PROBE_TIME_MS));
 	write_unlock_bh(&tbl->lock);
 }
 
···
 	    nla_put_msecs(skb, NDTPA_PROXY_DELAY,
 			  NEIGH_VAR(parms, PROXY_DELAY), NDTPA_PAD) ||
 	    nla_put_msecs(skb, NDTPA_LOCKTIME,
-			  NEIGH_VAR(parms, LOCKTIME), NDTPA_PAD))
+			  NEIGH_VAR(parms, LOCKTIME), NDTPA_PAD) ||
+	    nla_put_msecs(skb, NDTPA_INTERVAL_PROBE_TIME_MS,
+			  NEIGH_VAR(parms, INTERVAL_PROBE_TIME_MS), NDTPA_PAD))
 		goto nla_put_failure;
 	return nla_nest_end(skb, nest);
 
···
 	[NDTPA_ANYCAST_DELAY]		= { .type = NLA_U64 },
 	[NDTPA_PROXY_DELAY]		= { .type = NLA_U64 },
 	[NDTPA_LOCKTIME]		= { .type = NLA_U64 },
+	[NDTPA_INTERVAL_PROBE_TIME_MS]	= { .type = NLA_U64, .min = 1 },
 };
 
 static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh,
···
 				NEIGH_VAR_SET(p, DELAY_PROBE_TIME,
 					      nla_get_msecs(tbp[i]));
 				call_netevent_notifiers(NETEVENT_DELAY_PROBE_TIME_UPDATE, p);
+				break;
+			case NDTPA_INTERVAL_PROBE_TIME_MS:
+				NEIGH_VAR_SET(p, INTERVAL_PROBE_TIME_MS,
+					      nla_get_msecs(tbp[i]));
 				break;
 			case NDTPA_RETRANS_TIME:
 				NEIGH_VAR_SET(p, RETRANS_TIME,
···
 	return ret;
 }
 
+static int neigh_proc_dointvec_ms_jiffies_positive(struct ctl_table *ctl, int write,
+						   void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table tmp = *ctl;
+	int ret;
+
+	int min = msecs_to_jiffies(1);
+
+	tmp.extra1 = &min;
+	tmp.extra2 = NULL;
+
+	ret = proc_dointvec_ms_jiffies_minmax(&tmp, write, buffer, lenp, ppos);
+	neigh_proc_update(ctl, write);
+	return ret;
+}
+
 int neigh_proc_dointvec(struct ctl_table *ctl, int write, void *buffer,
 			size_t *lenp, loff_t *ppos)
 {
···
 #define NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(attr, name) \
 	NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_userhz_jiffies)
 
+#define NEIGH_SYSCTL_MS_JIFFIES_POSITIVE_ENTRY(attr, name) \
+	NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_ms_jiffies_positive)
+
 #define NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(attr, data_attr, name) \
 	NEIGH_SYSCTL_ENTRY(attr, data_attr, name, 0644, neigh_proc_dointvec_ms_jiffies)
 
···
 		NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(RETRANS_TIME, "retrans_time"),
 		NEIGH_SYSCTL_JIFFIES_ENTRY(BASE_REACHABLE_TIME, "base_reachable_time"),
 		NEIGH_SYSCTL_JIFFIES_ENTRY(DELAY_PROBE_TIME, "delay_first_probe_time"),
+		NEIGH_SYSCTL_MS_JIFFIES_POSITIVE_ENTRY(INTERVAL_PROBE_TIME_MS,
+						       "interval_probe_time_ms"),
 		NEIGH_SYSCTL_JIFFIES_ENTRY(GC_STALETIME, "gc_stale_time"),
 		NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(QUEUE_LEN_BYTES, "unres_qlen_bytes"),
 		NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(PROXY_QLEN, "proxy_qlen"),

net/decnet/dn_neigh.c

···
 			[NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
 			[NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
 			[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
+			[NEIGH_VAR_INTERVAL_PROBE_TIME_MS] = 5 * HZ,
 			[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
 			[NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
 			[NEIGH_VAR_PROXY_QLEN] = 0,

net/ipv4/arp.c

···
 			[NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
 			[NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
 			[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
+			[NEIGH_VAR_INTERVAL_PROBE_TIME_MS] = 5 * HZ,
 			[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
 			[NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
 			[NEIGH_VAR_PROXY_QLEN] = 64,

net/ipv6/ndisc.c

···
 			[NEIGH_VAR_RETRANS_TIME] = ND_RETRANS_TIMER,
 			[NEIGH_VAR_BASE_REACHABLE_TIME] = ND_REACHABLE_TIME,
 			[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
+			[NEIGH_VAR_INTERVAL_PROBE_TIME_MS] = 5 * HZ,
 			[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
 			[NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
 			[NEIGH_VAR_PROXY_QLEN] = 64,