netdev - Re: INFO: rcu detected stall in xfrm_hash

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Message-ID: <20181214145632.urh3n4vua66wvmkx@gondor.apana.org.au>
Date:   Fri, 14 Dec 2018 22:56:32 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     Florian Westphal <fw@...len.de>
Cc:     Wolfgang Walter <linux@...m.de>,
        David Miller <davem@...emloft.net>,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        steffen.klassert@...unet.com, christophe.gouault@...nd.com
Subject: Re: INFO: rcu detected stall in xfrm_hash_rebuild

On Fri, Dec 14, 2018 at 03:35:32PM +0100, Florian Westphal wrote:
>
> Ok.  An alternative would be to remove the support for
> policy hash table thresholds (which decide what kinds of policies
> go to exact table and which ones go into inexact ones), i.e.
> partially revert 880a6fab8f6ba5b5abe59ea6
> ("xfrm: configure policy hash table thresholds by netlink").
> 
> This would remove the need for the rehashing support that
> re-sorts the policies into either exact/inexact lists) when the
> those tunables are changed.
> 
> We could also easily convert the exact table to an rhashtable
> then if we wanted to.

We could also do both.  In fact that was the reason why I started
working on rhashtable in the first place.  The idea is to extend
the run-time rehashing to include both parts of the database.

So you would look up the old table/list combo and then move onto
the new one.

Of course I never had time to finish this and I think the entity
asking for this has moved onto something else.

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt