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Re: [PATCH v3 03/15] lockdep: Refactor lookup_chain_cache()

From Nilay Vaish <nilayvaish@gmail.com>
Newsgroups linux.kernel
Subject Re: [PATCH v3 03/15] lockdep: Refactor lookup_chain_cache()
Date 2016-09-15 17:40 +0200
Message-ID <shGVz-ku-5@gated-at.bofh.it> (permalink)
References <sgSvL-8uI-5@gated-at.bofh.it> <sgSFs-6J-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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?

--
Nilay

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Thread

[PATCH v3 03/15] lockdep: Refactor lookup_chain_cache() Byungchul Park <byungchul.park@lge.com> - 2016-09-13 12:00 +0200
  Re: [PATCH v3 03/15] lockdep: Refactor lookup_chain_cache() Nilay Vaish <nilayvaish@gmail.com> - 2016-09-15 17:40 +0200
    Re: [PATCH v3 03/15] lockdep: Refactor lookup_chain_cache() Byungchul Park <byungchul.park@lge.com> - 2016-09-19 05:30 +0200
      Re: [PATCH v3 03/15] lockdep: Refactor lookup_chain_cache() Nilay Vaish <nilayvaish@gmail.com> - 2016-09-19 18:40 +0200
        Re: [PATCH v3 03/15] lockdep: Refactor lookup_chain_cache() Byungchul Park <byungchul.park@lge.com> - 2016-09-20 04:10 +0200

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