Hi everyone, I was looking at the memcg_slabinfo.py drgn script that offers a replacement to the deprecated memory.kmem.slabinfo. I had some questions about how it collects the memcg slab stats: 1. Why does the script loop through all struct pages on the system? Wouldn't it be more efficient to loop for every kmem_cache, for every online kmem_cache_node, then loop through slabs_free, slabs_full, and slabs_partial lists? This seems more consistent with how /proc/slabinfo works, and more efficient. I tested this on SLAB using a crash script as I am unable to run drgn on my current setup. I am not sure how correct this would be for SLUB though. 2. Before looping through pages, why does the script collect all objcgs belonging to the desired memcg in a set, and then test every objcg in a slab page to see whether it belongs to that memcg. Wouldn't it be easier to just check objcg->memcg? AFAICT this gets updated as well when the objcg is reparented. Sorry for my ignorance if any of the assumptions I made are incorrect. I just wanted to get more understanding of the implementation decisions taken while writing the script. Thanks.
