On Wed, Nov 7, 2012 at 7:14 AM, David Sterba <dave@xxxxxxxx> wrote:
> On Mon, Oct 29, 2012 at 12:30:52PM +0800, zwu.kernel@xxxxxxxxx wrote:
>> +static struct hot_func_type *hot_func_get(const char *name)
>> +{
>> + struct hot_func_type *f, *h = &hot_func_def;
>> +
>> + spin_lock(&hot_func_list_lock);
>> + list_for_each_entry(f, &hot_func_list, list) {
>> + if (!strcmp(f->hot_func_name, name))
>> + h = f;
>
> You probably want to break here
Good catch, done, thanks.
>
>> + }
>> + spin_unlock(&hot_func_list_lock);
>> +
>> + return h;
>> +}
>> +
>> +int hot_func_register(struct hot_func_type *h)
>> +{
>> + struct hot_func_type *f, *t = NULL;
>> +
>> + /* register, don't allow duplicate names */
>> + spin_lock(&hot_func_list_lock);
>> + list_for_each_entry(f, &hot_func_list, list) {
>> + if (!strcmp(f->hot_func_name, h->hot_func_name))
>> + t = f;
>
> if duplicate names are not allowed, then a warning may make sense to
> let us know that something is wrong
done, thanks.
>
>> + }
>> +
>> + if (t) {
>> + spin_unlock(&hot_func_list_lock);
>> + return -EBUSY;
>> + }
>> +
>> + list_add_tail(&h->list, &hot_func_list);
>> + spin_unlock(&hot_func_list_lock);
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(hot_func_register);
>> --- a/include/linux/hot_tracking.h
>> +++ b/include/linux/hot_tracking.h
>> @@ -73,6 +75,25 @@ struct hot_range_item {
>> u32 len; /* length in bytes */
>> };
>>
>> +typedef u64 (hot_rw_freq_calc_fn) (struct timespec old_atime,
>> + struct timespec cur_time, u64 old_avg);
>> +typedef u32 (hot_temp_calc_fn) (struct hot_freq_data *freq_data);
>> +typedef bool (hot_is_obsolete_fn) (struct hot_freq_data *freq_data);
>
> I'm thinking, whether these typedefs are useful, similar ops structures
> do not introduce them, also when you pick a struct member names exactly
> same as the typedefs:
>
>> +struct hot_func_ops {
>> + hot_rw_freq_calc_fn *hot_rw_freq_calc_fn;
>> + hot_temp_calc_fn *hot_temp_calc_fn;
>> + hot_is_obsolete_fn *hot_is_obsolete_fn;
>> +};
>
> My suggestion is to make the types explicit in the structure.
sorry, i don't get your point, can you elaborate it about how to do this?
>
>> +/* identifies an hot func type */
>> +struct hot_func_type {
>> + char hot_func_name[HOT_NAME_MAX];
>
> 'name' would be sufficient IMHO
done, thanks.
>
>> + /* fields provided by specific FS */
>> + struct hot_func_ops ops;
>> + struct list_head list;
>> +};
>
> david
--
Regards,
Zhi Yong Wu
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