the interfaces look good to me.
Sep 25 2019
Jun 11 2018
Apr 18 2018
Apr 17 2018
Dec 5 2017
So you only have one new compression value in the BP? Have you looked at how this interacts with L2ARC when compressed ARC is disabled? See arc_cksum_is_equal(), I don't think this will work right, because you won't be able to reproduce the on-disk compressed data without knowing the compression level.
Sep 20 2017
@seanc OpenZFS/illumos has been at 4K chunk size since ABD was introduced. I'm not aware of any discussion around changing that.
Sep 17 2017
FYI - we use 1K ABD chunks at Delphix (on illumos), and we've found that up to 40% of memory can end up being wasted because of memory fragmentation. At least on illumos, the 1K ABD kmem cache will use slab size 4K (one page), so there are 4 chunks per slab. After eviction, we may have many partially-full slabs, which wastes the free chunks. We are considering implementing a kmem_move callback which would allow the free chunks to be consolidated, reducing the potential for memory waste. But it isn't done yet.
Jul 19 2016
Jun 13 2016
Dec 23 2015
looks good. Happy to have this upstream too.
Nov 10 2015
You can use the instructions here: https://github.com/openzfs/openzfs to submit a pull request and get regression tests. Then solicit code reviews to email@example.com.
Nov 2 2015
What is the use case for this? AFAIK it isn't possible to create all those holds with one zfs command (there's just "zfs holds -r <snapshot>" which creates a hold on one snapshot per filesystem.
Oct 25 2015
Oct 24 2015
This is a good start, but you also need to update the manpage and help message (see get_usage()).
Jun 20 2015
Jun 18 2015
Looks fine to me. FWIW, illumos appears to have flsll() in userland but not kernel. It's implemented similarly to highbit().