netdev - Re: Subject: [PATCH ipsec-next 0/8] xfrm: policy: convert lookups to rcu

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Date:	Fri, 12 Aug 2016 10:22:54 +0200
From:	Steffen Klassert <steffen.klassert@...unet.com>
To:	Florian Westphal <fw@...len.de>
CC:	<netdev@...r.kernel.org>
Subject: Re: Subject: [PATCH ipsec-next 0/8] xfrm: policy: convert lookups to
 rcu

On Thu, Aug 11, 2016 at 03:17:51PM +0200, Florian Westphal wrote:
> Since commit d188ba86dd07a72eb ("xfrm: add rcu protection to sk->sk_policy[]")
> sk_policy can rely on rcu protection.
> 
> This change allows to also use rcu in xfrm_policy_lookup_bytype and to
> avoid grabbing the read-sie policy lock during lookups.
> 
> read-side policy rwlock is converted to pure rcu, then the policy_lock is
> changed to a plain spinlock as only write-sides remain.
> 
> First few patches do some preparation work, the later ones remove
> the read-side locks, last patch converts rwlock to spinlock.
> 
> I tested this with rcu debug enabled and simple esp tunnel
> forwarding udp packets.
> 
> If you have better tests for this please let me know and I can re-run with
> that.
> 
> Florian Westphal (8):
>       xfrm: policy: use rcu versions for iteration and list add/del
>       xfrm: policy: prepare policy_bydst hash for rcu lookups
>       xfrm: policy: add sequence count to synchronize reads with hash resizes
>       xfrm: policy: use atomic_inc_not_zero in rcu section
>       xfrm: policy: make xfrm_policy_lookup_bytype lockless
>       xfrm: policy: only use rcu in xfrm_sk_policy_lookup
>       xfrm: policy: don't acquire policy lock in xfrm_spd_getinfo
>       xfrm: policy: convert policy_lock to spinlock
> 
>  include/net/netns/xfrm.h |    4 -
>  net/xfrm/xfrm_policy.c   |  145 +++++++++++++++++++++++++++--------------------
>  2 files changed, 88 insertions(+), 61 deletions(-)

Looks good, I've applied to already to the ipsec-next testing branch.
However, I'll be off for a week starting this afternoon, so I don't
see if the patchset passed all tests before I leave. For that I defer
the applying to master until I'm back.

Thanks!