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SubjectRe: [PATCH v3 03/15] lockdep: Refactor lookup_chain_cache()
On Thu, Sep 15, 2016 at 10:33:46AM -0500, Nilay Vaish wrote:
> On 13 September 2016 at 04:45, Byungchul Park <byungchul.park@lge.com> wrote:
> > @@ -2215,6 +2178,75 @@ cache_hit:
> > return 1;
> > }
> >
> > +/*
> > + * Look up a dependency chain.
> > + */
> > +static inline struct lock_chain *lookup_chain_cache(u64 chain_key)
> > +{
> > + struct hlist_head *hash_head = chainhashentry(chain_key);
> > + struct lock_chain *chain;
> > +
> > + /*
> > + * We can walk it lock-free, because entries only get added
> > + * to the hash:
> > + */
> > + hlist_for_each_entry_rcu(chain, hash_head, entry) {
> > + if (chain->chain_key == chain_key) {
> > + debug_atomic_inc(chain_lookup_hits);
> > + return chain;
> > + }
> > + }
> > + return NULL;
> > +}
>
> Byungchul, do you think we should increment chain_lookup_misses
> before returning NULL from the above function?

Hello,

No, I don't think so.
It will be done in add_chain_cache().

Thank you,
Byungchul

>
> --
> Nilay

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