[PATCH v3 28/49] dm zoned: dynamically allocate the dm-zoned-meta shrinker

[Qi Zheng]

On 2023/7/27 18:20, Damien Le Moal wrote:
> On 7/27/23 17:55, Qi Zheng wrote:
>>>>            goto err;
>>>>        }
>>>>    +    zmd->mblk_shrinker->count_objects = dmz_mblock_shrinker_count;
>>>> +    zmd->mblk_shrinker->scan_objects = dmz_mblock_shrinker_scan;
>>>> +    zmd->mblk_shrinker->seeks = DEFAULT_SEEKS;
>>>> +    zmd->mblk_shrinker->private_data = zmd;
>>>> +
>>>> +    shrinker_register(zmd->mblk_shrinker);
>>>
>>> I fail to see how this new shrinker API is better... Why isn't there a
>>> shrinker_alloc_and_register() function ? That would avoid adding all this code
>>> all over the place as the new API call would be very similar to the current
>>> shrinker_register() call with static allocation.
>>
>> In some registration scenarios, memory needs to be allocated in advance.
>> So we continue to use the previous prealloc/register_prepared()
>> algorithm. The shrinker_alloc_and_register() is just a helper function
>> that combines the two, and this increases the number of APIs that
>> shrinker exposes to the outside, so I choose not to add this helper.
> 
> And that results in more code in many places instead of less code + a simple
> inline helper in the shrinker header file... So not adding that super simple

It also needs to be exported to the driver for use.

> helper is not exactly the best choice in my opinion.

Hm, either one is fine for me. If no one else objects, I can add this
helper. ;)

>