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.... -Dave. -- Dave Chinner david@xxxxxxxxxxxxx
