From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wang Weidong Date: Mon, 02 Dec 2013 12:03:19 +0000 Subject: Re: [PATCH] sctp: make the max_burst min value to 1 Message-Id: <529C7707.5020908@huawei.com> List-Id: References: <529C2E01.3090005@huawei.com> <20131202115640.GA10857@hmsreliant.think-freely.org> In-Reply-To: <20131202115640.GA10857@hmsreliant.think-freely.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Neil Horman Cc: Vlad Yasevich , David Miller , linux-sctp@vger.kernel.org, netdev@vger.kernel.org, dingtianhong@huawei.com On 2013/12/2 19:56, Neil Horman wrote: > On Mon, Dec 02, 2013 at 02:51:45PM +0800, Wang Weidong wrote: >> From: Wang Weidong >> >> when I setted the max_burst to 0, do the lksctp-tools I got hang. >> I found sctp_transport_burst_limited would make the cwnd to 0. >> so I make the max_burst min value to 1. >> Signed-off-by: Wang Weidong >> --- >> net/sctp/sysctl.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c >> index 7637e8e..46832d3 100644 >> --- a/net/sctp/sysctl.c >> +++ b/net/sctp/sysctl.c >> @@ -135,7 +135,7 @@ static struct ctl_table sctp_net_table[] = { >> .maxlen = sizeof(int), >> .mode = 0644, >> .proc_handler = proc_dointvec_minmax, >> - .extra1 = &zero, >> + .extra1 = &one, >> .extra2 = &int_max >> }, >> { >> -- >> 1.7.12 >> >> > > > This seems like a band-aid to me. There are a few things wrong: > > 1) You can also set the the max_burst via setsockopt, and so this would need to > be checked in that path as well. > > 2) I don't see how having a cwnd of zero would cause a hang. It looks like a > cwnd of zero would perpetually place the association in a slow start state, > which is silly but not illegal. > Hm, Good suggestions. Ok, I will try it again and find the root cause. Thanks! > Please investigate the acutally root cause of the problem before just avoiding > it like this. > > Thanks! > Neil > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wang Weidong Subject: Re: [PATCH] sctp: make the max_burst min value to 1 Date: Mon, 2 Dec 2013 20:03:19 +0800 Message-ID: <529C7707.5020908@huawei.com> References: <529C2E01.3090005@huawei.com> <20131202115640.GA10857@hmsreliant.think-freely.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: Vlad Yasevich , David Miller , , , To: Neil Horman Return-path: Received: from szxga03-in.huawei.com ([119.145.14.66]:4668 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753519Ab3LBMDs (ORCPT ); Mon, 2 Dec 2013 07:03:48 -0500 In-Reply-To: <20131202115640.GA10857@hmsreliant.think-freely.org> Sender: netdev-owner@vger.kernel.org List-ID: On 2013/12/2 19:56, Neil Horman wrote: > On Mon, Dec 02, 2013 at 02:51:45PM +0800, Wang Weidong wrote: >> From: Wang Weidong >> >> when I setted the max_burst to 0, do the lksctp-tools I got hang. >> I found sctp_transport_burst_limited would make the cwnd to 0. >> so I make the max_burst min value to 1. >> Signed-off-by: Wang Weidong >> --- >> net/sctp/sysctl.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c >> index 7637e8e..46832d3 100644 >> --- a/net/sctp/sysctl.c >> +++ b/net/sctp/sysctl.c >> @@ -135,7 +135,7 @@ static struct ctl_table sctp_net_table[] = { >> .maxlen = sizeof(int), >> .mode = 0644, >> .proc_handler = proc_dointvec_minmax, >> - .extra1 = &zero, >> + .extra1 = &one, >> .extra2 = &int_max >> }, >> { >> -- >> 1.7.12 >> >> > > > This seems like a band-aid to me. There are a few things wrong: > > 1) You can also set the the max_burst via setsockopt, and so this would need to > be checked in that path as well. > > 2) I don't see how having a cwnd of zero would cause a hang. It looks like a > cwnd of zero would perpetually place the association in a slow start state, > which is silly but not illegal. > Hm, Good suggestions. Ok, I will try it again and find the root cause. Thanks! > Please investigate the acutally root cause of the problem before just avoiding > it like this. > > Thanks! > Neil > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > >