Re: [PATCH 4/6] bpf: hash: convert per-hashtable lock into per-bucket bit spinlock

[Alexei Starovoitov]

On Wed, Dec 16, 2015 at 02:58:08PM +0800, Ming Lei wrote:
> On Wed, Dec 16, 2015 at 1:01 PM, Yang Shi <shy828301@xxxxxxxxx> wrote:
> 
> >
> > I recalled Steven confirmed raw_spin_lock has the lockdep benefit too in the
> > patch review for changing to raw lock.
> >
> > Please check this thread out
> >  http://lists.openwall.net/netdev/2015/10/31/7
> 
> OK, looks I was wrong about the lockdep benifit, :-(
> 
> But for this lock, I think lockdep isn't such important, because it is the
> intermost lock, and it can be used just for protecting the bucket list
> and nothing else need to be covered.

I still think that overhead of normal spinlock per bucket is acceptable.
Makes the whole thing much easier to read.

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