From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Dmitry Kravkov" <dmitry@broadcom.com>
Subject: Re: [PATCH] bnx2x: fix panic when TX ring is full
Date: Thu, 21 Jun 2012 18:56:22 +0300
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Cc: "Tomas Hruby" <thruby@google.com>,
	"David Miller" <davem@davemloft.net>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"therbert@google.com" <therbert@google.com>,
	"evansr@google.com" <evansr@google.com>,
	"Eilon Greenstein" <eilong@broadcom.com>,
	"Merav Sicron" <meravs@broadcom.com>,
	"Yaniv Rosner" <yaniv.rosner@broadcom.com>,
	"willemb@google.com" <willemb@google.com>
To: "Eric Dumazet" <eric.dumazet@gmail.com>
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On Thu, 2012-06-21 at 17:12 +0200, Eric Dumazet wrote:
> On Thu, 2012-06-21 at 15:19 +0300, Dmitry Kravkov wrote:
> 
> > The crash happens with default configuration since
> > [4acb41903b2f99f3dffd4c3df9acc84ca5942cb2] "net/tcp: Fix tcp memory
> > limits initialization when !CONFIG_SYSCTL", but it can be hit by
> > increasing values of tcp_wmem even earlier.
> 
> This makes no sense.
Bisected to this commit and reproduced before the commit only after:
echo "4096 16384 4194304" > /proc/sys/net/ipv4/tcp_wmem
by this max nr_frags raised from 8 to 17, when running 40 netperfs

i've decreased rx queue to 200, during the test


> > From: Dmitry Kravkov <dmitry@broadcom.com>
> > Subject: [PATCH net-next] bnx2x: reservation for NEXT tx BDs
> > 
> > Commit [4acb41903b2f99f3dffd4c3df9acc84ca5942cb2]
> > net/tcp: Fix tcp memory limits initialization when !CONFIG_SYSCTL
> > provided new default value for tcp_wmem, since heavy tcp
> > traffic may cause the TSO packet to consume 20 BDs + 1 for next page
> > descriptor.
> 
> This is completely bogus. I have no idea how you came to this.
> 
> A forwarding workload can trigger same bug, if GRO is enabled.
> 
> Remove this wrong bit, please ?
> 
> 
>