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Commit be916cde authored by Jarek Poplawski's avatar Jarek Poplawski Committed by David S. Miller
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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: default avatarPawel Staszewski <pstaszewski@itcare.pl>
Reported-by: default avatarJorge Boncompte [DTI2] <jorge@dti2.net>
Tested-by: default avatarPawel Staszewski <pstaszewski@itcare.pl>
Signed-off-by: default avatarJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: default avatarRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c3059477

net/ipv4/fib_trie.c

+22 −7
Original line number Diff line number Diff line
@@ -327,6 +327,8 @@ static const int inflate_threshold = 50; 
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 @@ static struct node *resize(struct trie *t, struct tnode *tn) 
	/* 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 @@ static struct node *resize(struct trie *t, struct tnode *tn) 
	}



	if (max_resize < 0) {

		if (!tn->parent)

			pr_warning("Fix inflate_threshold_root."

				   " Now=%d size=%d bits\n",

				   inflate_threshold_root, tn->bits);

		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);