[IPV4]: Add gc_min_interval_ms sysctl.

The existing seconds based gc_min_interval is barely
usable.
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/filesystems/proc.txt

@@ -1709,12 +1709,13 @@ flush
 
 Writing to this file results in a flush of the routing cache.
 
-gc_elasticity, gc_interval, gc_min_interval, gc_tresh, gc_timeout,
-gc_thresh, gc_thresh1, gc_thresh2, gc_thresh3
---------------------------------------------------------------
+gc_elasticity, gc_interval, gc_min_interval_ms, gc_timeout, gc_thresh
+---------------------------------------------------------------------
 
 Values to  control  the  frequency  and  behavior  of  the  garbage collection
-algorithm for the routing cache.
+algorithm for the routing cache. gc_min_interval is deprecated and replaced
+by gc_min_interval_ms.
+
 
 max_size
 --------

include/linux/sysctl.h

@@ -365,6 +365,7 @@ enum {
 	NET_IPV4_ROUTE_MIN_PMTU=16,
 	NET_IPV4_ROUTE_MIN_ADVMSS=17,
 	NET_IPV4_ROUTE_SECRET_INTERVAL=18,
+	NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS=19,
 };
 
 enum

net/ipv4/route.c

@@ -2529,6 +2529,8 @@ ctl_table ipv4_route_table[] = {
 		.proc_handler	= &proc_dointvec,
 	},
 	{
+		/*  Deprecated. Use gc_min_interval_ms */
+ 
 		.ctl_name	= NET_IPV4_ROUTE_GC_MIN_INTERVAL,
 		.procname	= "gc_min_interval",
 		.data		= &ip_rt_gc_min_interval,
@@ -2537,6 +2539,15 @@ ctl_table ipv4_route_table[] = {
 		.proc_handler	= &proc_dointvec_jiffies,
 		.strategy	= &sysctl_jiffies,
 	},
+	{
+		.ctl_name	= NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS,
+		.procname	= "gc_min_interval_ms",
+		.data		= &ip_rt_gc_min_interval,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= &proc_doulongvec_ms_jiffies_minmax,
+		.strategy	= &sysctl_jiffies,
+	},
 	{
 		.ctl_name	= NET_IPV4_ROUTE_GC_TIMEOUT,
 		.procname	= "gc_timeout",