Re: [PATCH] performance problem with established hash

Anton Blanchard [off-list ref] wrote:

-		goal = min(10UL, goal);
 +		goal = min(1UL << 10, goal);

oops.  Better fix the route cache too.

I'm not sure what went wrong in there, sorry for letting that slip through.
Obviously, doing

	if (a)
		foo = bar;
	else
		foo = zot;

	if (b)
		foo = rab;
	else
		foo = toz;

does not make a ton of sense.

This should fix it up.  We keep the table sizing identical to that which
we had in 2.6.earlier, with a boot option override.


 net/ipv4/route.c |    4 +---
 net/ipv4/tcp.c   |    4 +---
 2 files changed, 2 insertions(+), 6 deletions(-)

diff -puN net/ipv4/route.c~ip_rt_init-sizing-fix net/ipv4/route.c

--- 25/net/ipv4/route.c~ip_rt_init-sizing-fix	2004-02-27 19:43:01.000000000 -0800
+++ 25-akpm/net/ipv4/route.c	2004-02-27 19:51:02.000000000 -0800

@@ -2753,9 +2753,7 @@ int __init ip_rt_init(void)
 		panic("IP: failed to allocate ip_dst_cache\n");
 
 	goal = num_physpages >> (26 - PAGE_SHIFT);
-	if (!rhash_entries)
-		goal = min(10, goal);
-	else
+	if (rhash_entries)
 		goal = (rhash_entries * sizeof(struct rt_hash_bucket)) >> PAGE_SHIFT;
 	for (order = 0; (1UL << order) < goal; order++)
 		/* NOTHING */;

diff -puN net/ipv4/tcp.c~ip_rt_init-sizing-fix net/ipv4/tcp.c

--- 25/net/ipv4/tcp.c~ip_rt_init-sizing-fix	2004-02-27 19:51:40.000000000 -0800
+++ 25-akpm/net/ipv4/tcp.c	2004-02-27 19:52:27.000000000 -0800

@@ -2621,9 +2621,7 @@ void __init tcp_init(void)
 	else
 		goal = num_physpages >> (23 - PAGE_SHIFT);
 
-	if (!thash_entries)
-		goal = min(10UL, goal);
-	else
+	if (thash_entries)
 		goal = (thash_entries * sizeof(struct tcp_ehash_bucket)) >> PAGE_SHIFT;
 	for (order = 0; (1UL << order) < goal; order++)
 		;

_