On 7/28/23 07:59, Dave Chinner wrote: > On Thu, Jul 27, 2023 at 07:20:46PM +0900, 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... > > It's not just a "simple helper" - it's a function that has to take 6 > or 7 parameters with a return value that must be checked and > handled. > > This was done in the first versions of the patch set - the amount of > code in each caller does not go down and, IMO, was much harder to > read and determine "this is obviously correct" that what we have > now. > >> So not adding that super simple >> helper is not exactly the best choice in my opinion. > > Each to their own - I much prefer the existing style/API over having > to go look up a helper function every time I want to check some > random shrinker has been set up correctly.... OK. All fair points. -- Damien Le Moal Western Digital Research
