Date: Wed, 26 Sep 2012 15:38:11 -0400 From: John Baldwin <jhb@freebsd.org> To: Ryan Stone <rysto32@gmail.com> Cc: freebsd-net@freebsd.org, Jack Vogel <jfvogel@gmail.com>, Vijay Singh <vijju.singh@gmail.com> Subject: Re: ixgbe rx & tx locks Message-ID: <201209261538.11588.jhb@freebsd.org> In-Reply-To: <CAFMmRNwUpO-=PvdPVisrD%2BkicS5WA-cn%2BXsdjRGt5JfSokRSjQ@mail.gmail.com> References: <CALCNsJSSQSWV7vNVR-Sn8CPDKbUBBLpSH0b-HYMJo3SXvkOY=w@mail.gmail.com> <201209260955.14417.jhb@freebsd.org> <CAFMmRNwUpO-=PvdPVisrD%2BkicS5WA-cn%2BXsdjRGt5JfSokRSjQ@mail.gmail.com>
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On Wednesday, September 26, 2012 3:08:22 pm Ryan Stone wrote: > On Wed, Sep 26, 2012 at 9:55 AM, John Baldwin <jhb@freebsd.org> wrote: > > You only have to drop the RX lock around if_input() if you use the same lock > > for both TX and RX (as if_transmit() / if_start() can be invoked while locks > > in the network stack are held). > > Last time I checked(FreeBSD 8.2), this is not true. The problematic > (and convoluted) ordering is: > > ix:rx -> udp -> udpinp -> in_multi_mtx -> ix:core -> ix:rx Hmm, I'm not sure where the 'in_multi_mtx -> ix:core' bit comes from. I think that is the broken part of this. The SIOCADDMULTI and SIOCDELMULTI ioctls are invoked without any stack locks held, so it shouldn't come from there. -- John Baldwin
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