ipv4: Fix inflate_threshold_root automatically
During large updates there could be triggered warnings like: "Fix
inflate_threshold_root. Now=25 size=11 bits" if inflate() of the root
node isn't finished in 10 loops. It should be much rarer now, after
changing the threshold from 15 to 25, and a temporary problem, so
this patch tries to handle it automatically using a fix variable to
increase by one inflate threshold for next root resizes (up to the 35
limit, max fix = 10). The fix variable is decreased when root's
inflate() finishes below 7 loops (even if some other, smaller table/
trie is updated -- for simplicity the fix variable is global for now).
Reported-by: Pawel Staszewski <pstaszewski@itcare.pl>
Reported-by: Jorge Boncompte [DTI2] <jorge@dti2.net>
Tested-by: Pawel Staszewski <pstaszewski@itcare.pl>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 58ba9f4..5741d13 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -327,6 +327,8 @@
static const int halve_threshold_root = 15;
static const int inflate_threshold_root = 25;
+static int inflate_threshold_root_fix;
+#define INFLATE_FIX_MAX 10 /* a comment in resize() */
static void __alias_free_mem(struct rcu_head *head)
{
@@ -617,7 +619,8 @@
/* Keep root node larger */
if (!tn->parent)
- inflate_threshold_use = inflate_threshold_root;
+ inflate_threshold_use = inflate_threshold_root +
+ inflate_threshold_root_fix;
else
inflate_threshold_use = inflate_threshold;
@@ -641,15 +644,27 @@
}
if (max_resize < 0) {
- if (!tn->parent)
- pr_warning("Fix inflate_threshold_root."
- " Now=%d size=%d bits\n",
- inflate_threshold_root, tn->bits);
- else
+ if (!tn->parent) {
+ /*
+ * It was observed that during large updates even
+ * inflate_threshold_root = 35 might be needed to avoid
+ * this warning; but it should be temporary, so let's
+ * try to handle this automatically.
+ */
+ if (inflate_threshold_root_fix < INFLATE_FIX_MAX)
+ inflate_threshold_root_fix++;
+ else
+ pr_warning("Fix inflate_threshold_root."
+ " Now=%d size=%d bits fix=%d\n",
+ inflate_threshold_root, tn->bits,
+ inflate_threshold_root_fix);
+ } else {
pr_warning("Fix inflate_threshold."
" Now=%d size=%d bits\n",
inflate_threshold, tn->bits);
- }
+ }
+ } else if (max_resize > 3 && !tn->parent && inflate_threshold_root_fix)
+ inflate_threshold_root_fix--;
check_tnode(tn);