| Message ID | 20190326153026.24493-4-dima@arista.com |
|---|---|
| State | RFC |
| Delegated to: | David Miller |
| Headers | show |
| Series | net/fib: Speed up trie rebalancing for full view | expand |
On Tue, 2019-03-26 at 15:30 +0000, Dmitry Safonov wrote: > Those functions are compute-costly, if we're out of budget - better > omit additional computations. > > Signed-off-by: Dmitry Safonov <dima@arista.com> > --- > net/ipv4/fib_trie.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c > index d90cf9dfd443..2ce2739e7693 100644 > --- a/net/ipv4/fib_trie.c > +++ b/net/ipv4/fib_trie.c > @@ -868,7 +868,7 @@ static struct key_vector *resize(struct trie *t, struct key_vector *tn, > /* Double as long as the resulting node has a number of > * nonempty nodes that are above the threshold. > */ > - while (should_inflate(tp, tn) && *budget) { > + while (*budget && should_inflate(tp, tn)) { > tp = inflate(t, tn, budget); > if (!tp) { > #ifdef CONFIG_IP_FIB_TRIE_STATS > @@ -894,7 +894,7 @@ static struct key_vector *resize(struct trie *t, struct key_vector *tn, > /* Halve as long as the number of empty children in this > * node is above threshold. > */ > - while (should_halve(tp, tn) && *budget) { > + while (*budget && should_halve(tp, tn)) { > tp = halve(t, tn, budget); > if (!tp) { > #ifdef CONFIG_IP_FIB_TRIE_STATS Based on my comments in the other patches I would say this is a bad idea. Really the budget should allow at least 1 pass through the trie to attempt to either inflate or deflate the node and all children. This logic is optimizing for the case where *budget is 0 and that should not occur that often.
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index d90cf9dfd443..2ce2739e7693 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -868,7 +868,7 @@ static struct key_vector *resize(struct trie *t, struct key_vector *tn, /* Double as long as the resulting node has a number of * nonempty nodes that are above the threshold. */ - while (should_inflate(tp, tn) && *budget) { + while (*budget && should_inflate(tp, tn)) { tp = inflate(t, tn, budget); if (!tp) { #ifdef CONFIG_IP_FIB_TRIE_STATS @@ -894,7 +894,7 @@ static struct key_vector *resize(struct trie *t, struct key_vector *tn, /* Halve as long as the number of empty children in this * node is above threshold. */ - while (should_halve(tp, tn) && *budget) { + while (*budget && should_halve(tp, tn)) { tp = halve(t, tn, budget); if (!tp) { #ifdef CONFIG_IP_FIB_TRIE_STATS
Those functions are compute-costly, if we're out of budget - better omit additional computations. Signed-off-by: Dmitry Safonov <dima@arista.com> --- net/ipv4/fib_trie.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)