diff options
| author | Jon Maxwell <jmaxwell37@gmail.com> | 2023-01-12 12:25:32 +1100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-01-13 20:59:14 -0800 |
| commit | af6d10345ca76670c1b7c37799f0d5576ccef277 (patch) | |
| tree | 63bbdea43a5d2a8d75db45781f8c7b8004bcefa9 /net/core | |
| parent | c1917514107982794fd448ee2596878f396ee6a8 (diff) | |
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 <andrea.mayer@uniroma2.it>
Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230112012532.311021-1-jmaxwell37@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dst.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/net/core/dst.c b/net/core/dst.c index 6d2dd03dafa8..31c08a3386d3 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -82,12 +82,8 @@ void *dst_alloc(struct dst_ops *ops, struct net_device *dev, if (ops->gc && !(flags & DST_NOCOUNT) && - dst_entries_get_fast(ops) > ops->gc_thresh) { - if (ops->gc(ops)) { - pr_notice_ratelimited("Route cache is full: consider increasing sysctl net.ipv6.route.max_size.\n"); - return NULL; - } - } + dst_entries_get_fast(ops) > ops->gc_thresh) + ops->gc(ops); dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC); if (!dst) |