Date: Wed, 8 Apr 2015 10:36:18 -0700 From: Adrian Chadd <adrian@freebsd.org> To: Gleb Smirnoff <glebius@freebsd.org> Cc: "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r281239 - head/sys/netinet Message-ID: <CAJ-VmonNwsor=7c_kE82cY7TebCWFa1gX0DH8QQH%2B6EqR%2B_RRg@mail.gmail.com> In-Reply-To: <20150408084839.GO64665@FreeBSD.org> References: <201504072309.t37N9Zwf011383@svn.freebsd.org> <20150408084839.GO64665@FreeBSD.org>
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hi gleb,
/* Skip initialization of globals for non-default instances. */
if (!IS_DEFAULT_VNET(curvnet))
return;
.. ie, no. It doesn't double-init the mutexes.
And the purging from bucket behaviour should have been precisely what
the previous behaviour was.
/*
* drop something from the tail of the current queue
* before proceeding further
*/
.. if you'd like to fix that then cool, but it's orthogonal to what I
was trying to do. I didn't want to go and do multiple things in one
patch set - this was /just/ to unroll the per-bucket locking. If you'd
like to fix the existing potentially risky bucket purging code in the
ip reassembly code then cool, let's do it - but in a separate
patchset.
V_nipq leaking is something we both missed during that review cycle.
I'm glad you caught it now.
-adrian
On 8 April 2015 at 01:48, Gleb Smirnoff <glebius@freebsd.org> wrote:
> On Tue, Apr 07, 2015 at 11:09:35PM +0000, Adrian Chadd wrote:
> A> Author: adrian
> A> Date: Tue Apr 7 23:09:34 2015
> A> New Revision: 281239
> A> URL: https://svnweb.freebsd.org/changeset/base/281239
> A>
> A> Log:
> A> Move the IPv4 reassembly queue locking from a single lock to be per-bucket (global).
> A>
> A> This significantly improves performance on multi-core servers where there
> A> is any kind of IPv4 reassembly going on.
> A>
> A> glebius@ would like to see the locking moved to be attached to the reassembly
> A> bucket, which would make it per-bucket + per-VNET, instead of being global.
> A> I decided to keep it global for now as it's the minimal useful change;
> A> if people agree / wish to migrate it to be per-bucket / per-VNET then please
> A> do feel free to do so. I won't complain.
> A>
> A> Thanks to Norse Corp for giving me access to much larger servers
> A> to test this at across the 4 core boxes I have at home.
> A>
> A> Differential Revision: https://reviews.freebsd.org/D2095
> A> Reviewed by: glebius (initial comments incorporated into this patch)
>
> No, they are not.
>
> Also, I just noticed another issue with the patch. You initialize the mutexes,
> which are global, in the ip_init() which is called for every VNET. That would
> lead to panic of initializing already initialized mutex. If you followed my advice,
> that would not happen. Now VIMAGE+INVARIANTS is broken instantly, and w/o
> INVARIANTS may panic if VIMAGE created under IP traffic.
>
> My comment that purging from a bucket that is determined by source IP has
> security implications was also ignored.
>
> I will fix this all myself.
>
> --
> Totus tuus, Glebius.
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