On Thu, Sep 28, 2023 at 10:24:34AM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
>
> Add traceeval_count() that will return the number of elements in the
> traceeval. This can be useful for allocating an array to store the
> elements. By getting the count, the allocation can be done first and
> then iterated to load the elements into the array.
>
> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
> ---
> include/traceeval-hist.h | 2 ++
> src/histograms.c | 11 +++++++++++
> 2 files changed, 13 insertions(+)
>
> diff --git a/include/traceeval-hist.h b/include/traceeval-hist.h
> index eefa48d..44d071f 100644
> --- a/include/traceeval-hist.h
> +++ b/include/traceeval-hist.h
> @@ -204,6 +204,8 @@ int traceeval_query_size(struct traceeval *teval, const struct traceeval_data *k
> void traceeval_results_release(struct traceeval *teval,
> const struct traceeval_data *results);
>
> +size_t traceeval_count(struct traceeval *teval);
> +
> #define traceeval_stat(teval, keys, type) \
> traceeval_stat_size(teval, keys, TRACEEVAL_ARRAY_SIZE(keys), type)
>
> diff --git a/src/histograms.c b/src/histograms.c
> index 2456342..ac3f7f7 100644
> --- a/src/histograms.c
> +++ b/src/histograms.c
> @@ -1006,6 +1006,17 @@ int traceeval_remove_size(struct traceeval *teval,
> return 1;
> }
>
> +/**
> + * traceeval_count - Return the number of elements in the traceeval
> + * @teval: The traceeval handle to get the count from
> + *
> + * Returns the number of elements stored by unique keys in the @teval.
> + */
> +size_t traceeval_count(struct traceeval *teval)
> +{
> + return teval->update_counter;
I don't think this is going to do what you want. 'teval->update_counter'
is a generation number, is monotonically increasing, and is incremented any
time an element is added or removed from the hash.
I think we either need to actually keep an element count (increment in
create_entry(), decrement in traceeval_remove_size() and
traceeval_iterator_remove()), or else we're going to have to count the
elements by walking the 'struct hash_table' buckets. Probably easier to just
keep an explicit element count.
> +}
> +
> /**
> * traceeval_iterator_put - release a given iterator
> * @iter: The iterartor to release
> --
> 2.40.1
>
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