Re: [PATCH v2] btrfs: Turn delayed_nodes_tree into an XArray

[Gabriel Niebler <gniebler@suse.com>]

Am 13.04.22 um 16:14 schrieb David Sterba:
> On Tue, Apr 12, 2022 at 02:35:46PM +0200, Gabriel Niebler wrote:
>> [...]
>> ---
>>
>> Notes:
>>      XArrays offer a somewhat nicer API than radix trees and were implemented
>>      specifically to replace the latter. They utilize the exact same underlying
>>      data structure, but their API is notionally easier to use, as it provides
>>      array semantics to the user of radix trees. The higher level API also
>>      takes care of locking, adding even more ease of use.
>>      
>>      The btrfs code uses radix trees in several places. This patch only
>>      converts the `delayed_nodes_tree` member of the btrfs_root struct.
> 
> You've put this under the --- marker which means this is not supposed to
> be in the changelog (as we do for various patch revision commments) [...]

I did, because I thought that my general waffling about XArrays is not 
something we need to have in the kernel changelog forerver, however...

> [...] but
> then there would be basically no useful changelog left. [...]

That's a good point. I kind of forgot that a good commit message is 
supposed to say *why* something was done and not just *what* was done, 
as that's obvious from the diff.

> [...] That the
> conversion is done is clear, maybe there are some useful notes or
> comments what changed and how, eg. the locking.

I'll try to come up with something more satisfying, yet not too verbose.