On Fri 15-11-19 12:36:34, Theodore Y. Ts'o wrote: > On Fri, Nov 15, 2019 at 03:56:38PM +0100, Jan Kara wrote: > > With some effort, we could even shrink struct buffer_head from 104 bytes > > (on x86_64) to 96 bytes but I don't think that effort is worth it (I'd find > > it better use of time to actually work on getting rid of buffer heads > > completely). > > Is that really realistic? All aside from the very large number of > file systems which use buffer_heads that would have to be reworked, > the concept of buffer heads is pretty fundamental to how jbd2 is > architected. I think it is reasonably possible to remove buffer_heads from data path (including direct IO path) of all filesystems. That way memory consumption of buffer_heads becomes mostly irrelevant and we can have a look how much from the current bh framework still makes sense... Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
