Re: [PATCH] performance problem with established hash

[Andrew Morton <akpm@xxxxxxxx>]

Anton Blanchard <anton@xxxxxxxxx> 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++)
                ;

_