On Oct 21, 2010, at 3:38 PM, Trond Myklebust wrote:
> On Thu, 2010-10-21 at 13:33 -0500, Ben Myers wrote:
>> Retry bind for reserved source ports forever. Add an error message when we
>> have a hard time binding one.
>
> NACK. This approach leads to the process spinning forever in that loop,
> which is exactly why we introduced the limit in the first place. See all
> the old archived bug report emails about 'rpciod taking 100% cpu'.
The root problem seems to be the hard loop. Thinking out loud, what if the client's FSM or some other higher up layer performed the retry, with a short delay inserted after each attempt?
> Cheers
> Trond
>
>> Signed-off-by: Ben Myers <bpm@xxxxxxx>
>> ---
>> net/sunrpc/xprtsock.c | 22 ++++++++++++++++++----
>> 1 files changed, 18 insertions(+), 4 deletions(-)
>>
>> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
>> index b6309db..79a001b 100644
>> --- a/net/sunrpc/xprtsock.c
>> +++ b/net/sunrpc/xprtsock.c
>> @@ -1560,9 +1560,16 @@ static int xs_bind4(struct sock_xprt *transport, struct socket *sock)
>> }
>> last = port;
>> port = xs_next_srcport(transport, sock, port);
>> - if (port > last)
>> + if (port > last) {
>> + if (nloop > 2 && net_ratelimit()) {
>> + printk("RPC: %s %pI4: Cannot bind reserved "
>> + "source port. Consider decreasing "
>> + "min_resvport.\n",
>> + __func__, &myaddr.sin_addr);
>> + }
>> nloop++;
>> - } while (err == -EADDRINUSE && nloop != 2);
>> + }
>> + } while (err == -EADDRINUSE);
>> dprintk("RPC: %s %pI4:%u: %s (%d)\n",
>> __func__, &myaddr.sin_addr,
>> port, err ? "failed" : "ok", err);
>> @@ -1593,9 +1600,16 @@ static int xs_bind6(struct sock_xprt *transport, struct socket *sock)
>> }
>> last = port;
>> port = xs_next_srcport(transport, sock, port);
>> - if (port > last)
>> + if (port > last) {
>> + if (nloop > 2 && net_ratelimit()) {
>> + printk("RPC: %s %pI6: Cannot bind reserved "
>> + "source port. Consider decreasing "
>> + "min_resvport.\n",
>> + __func__, &myaddr.sin6_addr);
>> + }
>> nloop++;
>> - } while (err == -EADDRINUSE && nloop != 2);
>> + }
>> + } while (err == -EADDRINUSE);
>> dprintk("RPC: xs_bind6 %pI6:%u: %s (%d)\n",
>> &myaddr.sin6_addr, port, err ? "failed" : "ok", err);
>> return err;
>>
>> --
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>
>
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--
chuck[dot]lever[at]oracle[dot]com
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