On Fri, 15 Sep 2023, Chuck Lever III wrote: > > > On Sep 11, 2023, at 9:30 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > On Tue, 12 Sep 2023 09:19:59 +1000 "NeilBrown" <neilb@xxxxxxx> wrote: > > > >> Plain old list_heads (which the code currently uses) require a spinlock > >> to be taken to insert something into the queue. As this is usually in > >> bh context, it needs to be a spin_lock_bh(). My understanding is that > >> the real-time developers don't much like us disabling bh. It isn't an > >> enormous win switching from a list_head list to a llist_node list, but > >> there are small gains such as object size reduction and less locking. I > >> particularly wanted an easy-to-use library facility that could be > >> plugged in to two different uses cases in the sunrpc code and there > >> didn't seem to be one. I could have written one using list_head, but > >> llist seemed a better fix. I think the code in sunrpc that uses this > >> lwq looks a lot neater after the conversion. > > > > Thanks. Could we please get words such as these into the changelog, > > describing why it was felt necessary to add more library code? > > > > And also into the .c file, to help people who are looking at it and > > wondering "can I use this". And to help reviewers who are wondering > > "could they have used Neil's thing". > > Neil, are you planning to send along a replacement for 11/17, > or would you like me to fold the above into the patch description > I have now? Sorry I didn't reply sooner - been busy. I'll send a patch that can be squashed in to 11/17 which adds some more explanatory text. Hopefully soonish. NeilBrown
