From af6d10345ca76670c1b7c37799f0d5576ccef277 Mon Sep 17 00:00:00 2001 From: Jon Maxwell Date: Thu, 12 Jan 2023 12:25:32 +1100 Subject: ipv6: remove max_size check inline with ipv4 In ip6_dst_gc() replace: if (entries > gc_thresh) With: if (entries > ops->gc_thresh) Sending Ipv6 packets in a loop via a raw socket triggers an issue where a route is cloned by ip6_rt_cache_alloc() for each packet sent. This quickly consumes the Ipv6 max_size threshold which defaults to 4096 resulting in these warnings: [1] 99.187805] dst_alloc: 7728 callbacks suppressed [2] Route cache is full: consider increasing sysctl net.ipv6.route.max_size. . . [300] Route cache is full: consider increasing sysctl net.ipv6.route.max_size. When this happens the packet is dropped and sendto() gets a network is unreachable error: remaining pkt 200557 errno 101 remaining pkt 196462 errno 101 . . remaining pkt 126821 errno 101 Implement David Aherns suggestion to remove max_size check seeing that Ipv6 has a GC to manage memory usage. Ipv4 already does not check max_size. Here are some memory comparisons for Ipv4 vs Ipv6 with the patch: Test by running 5 instances of a program that sends UDP packets to a raw socket 5000000 times. Compare Ipv4 and Ipv6 performance with a similar program. Ipv4: Before test: MemFree: 29427108 kB Slab: 237612 kB ip6_dst_cache 1912 2528 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 2881 3990 192 42 2 : tunables 0 0 0 During test: MemFree: 29417608 kB Slab: 247712 kB ip6_dst_cache 1912 2528 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 44394 44394 192 42 2 : tunables 0 0 0 After test: MemFree: 29422308 kB Slab: 238104 kB ip6_dst_cache 1912 2528 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 3048 4116 192 42 2 : tunables 0 0 0 Ipv6 with patch: Errno 101 errors are not observed anymore with the patch. Before test: MemFree: 29422308 kB Slab: 238104 kB ip6_dst_cache 1912 2528 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 3048 4116 192 42 2 : tunables 0 0 0 During Test: MemFree: 29431516 kB Slab: 240940 kB ip6_dst_cache 11980 12064 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 3048 4116 192 42 2 : tunables 0 0 0 After Test: MemFree: 29441816 kB Slab: 238132 kB ip6_dst_cache 1902 2432 256 32 2 : tunables 0 0 0 xfrm_dst_cache 0 0 320 25 2 : tunables 0 0 0 ip_dst_cache 3048 4116 192 42 2 : tunables 0 0 0 Tested-by: Andrea Mayer Signed-off-by: Jon Maxwell Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230112012532.311021-1-jmaxwell37@gmail.com Signed-off-by: Jakub Kicinski --- include/net/dst_ops.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/net/dst_ops.h') diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h index 88ff7bb2bb9b..632086b2f644 100644 --- a/include/net/dst_ops.h +++ b/include/net/dst_ops.h @@ -16,7 +16,7 @@ struct dst_ops { unsigned short family; unsigned int gc_thresh; - int (*gc)(struct dst_ops *ops); + void (*gc)(struct dst_ops *ops); struct dst_entry * (*check)(struct dst_entry *, __u32 cookie); unsigned int (*default_advmss)(const struct dst_entry *); unsigned int (*mtu)(const struct dst_entry *); -- cgit v1.2.3