On Mon 03-06-24 22:43:16, JunChao Sun wrote: > Jan Kara <jack@xxxxxxx> 于2024年6月3日周一 22:07写道： > > > > On Mon 03-06-24 21:15:24, Junchao Sun wrote: > > > Using pahole, we can see that there are some padding holes > > > in the current ext4_inode_info structure. Adjusting the > > > layout of ext4_inode_info can reduce these holes, > > > resulting in the size of the structure decreasing > > > from 2424 bytes to 2408 bytes. > > > > > > > But AFAICT this will save two holes 4 bytes each so only 8 bytes in total? > > > Not 16? > > Indeed it's 16. > Consider the layout int a; hole 0; int b; hole 1; And then move int b > to hole 0 position, this adjustment resulted in saving 8 bytes. There > are two adjustments like this, so it's 16. And GDB confirmed this. Aha, OK. Thanks for clarification! Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
