On Sun, Jul 05, 2009 at 06:20:03PM +0200, Jarek Poplawski wrote:

quoted text
> On Sun, Jul 05, 2009 at 02:30:03AM +0200, Paweł Staszewski wrote:

> > Oh

> >

> > I forgot - please Jarek give me patch with sync rcu and i will make test

> > on preempt kernel

>

> Probably non-preempt kernel might need something like this more, but

> comparing is always interesting. This patch is based on Paul's

> suggestion (I hope).

Hold on ;-) Here is something even better... Syncing after 128 pages

might be still too slow, so here is a higher initial value, 1000, plus

you can change this while testing in:
/sys/module/fib_trie/parameters/sync_pages
It would be interesting to find the lowest acceptable value.
Jarek P.

---> (synchronize take 8; apply on top of the 2.6.29.x with the last

 	all-in-one patch, or net-2.6)
 net/ipv4/fib_trie.c |   12 ++++++++++++

 1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c

index 00a54b2..decc8d0 100644

--- a/net/ipv4/fib_trie.c

+++ b/net/ipv4/fib_trie.c

@@ -71,6 +71,7 @@

 #include

 #include

 #include

+#include

 #include

 #include

 #include

@@ -164,6 +165,10 @@ static struct tnode *inflate(struct trie *t, struct tnode *tn);

 static struct tnode *halve(struct trie *t, struct tnode *tn);

 /* tnodes to free after resize(); protected by RTNL */

 static struct tnode *tnode_free_head;

+static size_t tnode_free_size;

+

+static int sync_pages __read_mostly = 1000;

+module_param(sync_pages, int, 0640);
 static struct kmem_cache *fn_alias_kmem __read_mostly;

 static struct kmem_cache *trie_leaf_kmem __read_mostly;

@@ -393,6 +398,8 @@ static void tnode_free_safe(struct tnode *tn)

 	BUG_ON(IS_LEAF(tn));

 	tn->tnode_free = tnode_free_head;

 	tnode_free_head = tn;

+	tnode_free_size += sizeof(struct tnode) +

+			   (sizeof(struct node *) << tn->bits);

 }
 static void tnode_free_flush(void)

@@ -404,6 +411,11 @@ static void tnode_free_flush(void)

 		tn->tnode_free = NULL;

 		tnode_free(tn);

 	}

+

+	if (tnode_free_size >= PAGE_SIZE * sync_pages) {

+		tnode_free_size = 0;

+		synchronize_rcu();

+	}

 }
 static struct leaf *leaf_new(void)

--

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