In some testing scenarios, dst/route cache can fill up so quickly
that even an explicit GC call occasionally fails to clean it up. This leads
to sporadically failing calls to dst_alloc and "network unreachable" errors
to the user, which is confusing.
This patch adds a diagnostic message to make the cause of the failure
easier to determine.
Signed-off-by: Peter Oskolkov <p...@google.com>
---
net/core/dst.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/core/dst.c b/net/core/dst.c
index 81ccf20e2826..a263309df115 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -98,8 +98,12 @@ void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
struct dst_entry *dst;
if (ops->gc && dst_entries_get_fast(ops) > ops->gc_thresh) {
- if (ops->gc(ops))
+ if (ops->gc(ops)) {
+ printk_ratelimited(KERN_NOTICE "Route cache is full: "
+ "consider increasing sysctl "
+ "net.ipv[4|6].route.max_size.\n");
return NULL;
+ }
}
dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC);
--
