On 04/14/2018 07:19 PM, Baoquan He wrote: >>> Yes, this place is the hardest to understand. The temorary arrays are >>> allocated beforehand with the size of 'nr_present_sections'. The error >>> paths you mentioned is caused by allocation failure of mem_map or >>> map_map, but whatever it's error or success paths, the sections must be >>> marked as present in memory_present(). Error or success paths happened >>> in alloc_usemap_and_memmap(), while checking if it's erorr or success >>> paths happened in the last for_each_present_section_nr() of >>> sparse_init(), and clear the ms->section_mem_map if it goes along error >>> paths. This is the key point of this new allocation way. >> I think you owe some commenting because this is so hard to understand. > I can arrange and write a code comment above sparse_init() according to > this patch's git log, do you think it's OK? > > Honestly, it took me several days to write code, while I spent more > than one week to write the patch log. Writing patch log is really a > headache to me. I often find the same: writing the code is the easy part. Explaining why it is right is the hard part.
