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SubjectRe: [PATCH] trace-cmd: add trace_hash_find_reverse
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On 02/23/2016 05:26 PM, Steven Rostedt wrote:
> On Tue, 15 Dec 2015 11:13:24 -0500
> Josef Bacik <jbacik@fb.com> wrote:
>
>> Sometimes we want to FIFO identical entries in the hash table, so add
>> trace_hash_find_reverse, which will cycle through the hash list in reverse.
>> This is helpful in our case where we are monitoring block request issues to
>> match with their corresponding completes, if we issue multiple times to the same
>> block we want to be able to match them with the correct completes (more or less
>> anyway). Thanks,
>>
>> Signed-off-by: Josef Bacik <jbacik@fb.com>
>> ---
>> list.h | 5 +++++
>> trace-hash.c | 22 ++++++++++++++++++++++
>> 2 files changed, 27 insertions(+)
>>
>> diff --git a/list.h b/list.h
>> index 9817871..93c64f5 100644
>> --- a/list.h
>> +++ b/list.h
>> @@ -79,4 +79,9 @@ static inline int list_empty(struct list_head *list)
>> &(p)->field != list; \
>> p = n, n = container_of((p)->field.next, typeof(*p), field))
>>
>> +#define list_for_each_entry_reverse(p, list, field) \
>> + for (p = container_of((list)->prev, typeof(*p), field); \
>> + &p->field != list; \
>> + p = container_of((p)->field.prev, typeof(*p), field))
>> +
>> #endif /* __LIST_H */
>> diff --git a/trace-hash.c b/trace-hash.c
>> index 5ffe61c..0dc4f73 100644
>> --- a/trace-hash.c
>> +++ b/trace-hash.c
>> @@ -94,3 +94,25 @@ trace_hash_find(struct trace_hash *hash, unsigned long long key,
>>
>> return NULL;
>> }
>> +
>> +struct trace_hash_item *
>> +trace_hash_find_reverse(struct trace_hash *hash, unsigned long long key,
>> + trace_hash_func match, void *data)
>> +{
>> + struct trace_hash_item *item;
>> + struct list_head *bucket;
>> + int bucket_nr = hash->power ? key & hash->power :
>> + key % hash->nr_buckets;
>> +
>> + bucket = hash->buckets + bucket_nr;
>> + list_for_each_entry_reverse(item, bucket, list) {
>
> Strange, this doesn't compile.
>
> "struct trace_hash_item has no member named list"
>

Sorry I sent out the wrong version of this patch. I don't actually need
this anymore so you can just drop it. Thanks,

Josef

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