Re: [dm-devel] [PATCH v2 01/14] block: Generalized bio pool freeing

[Tejun Heo <tj kernel org>]

On Thu, May 24, 2012 at 09:09:44AM -0700, Tejun Heo wrote:
> On Wed, May 23, 2012 at 05:02:38PM -0700, Kent Overstreet wrote:
> > With the old code, when you allocate a bio from a bio pool you have to
> > implement your own destructor that knows how to find the bio pool the
> > bio was originally allocated from.
> > 
> > This adds a new field to struct bio (bi_pool) and changes
> > bio_alloc_bioset() to use it. This makes various bio destructors
> > unnecessary, so they're then deleted.
> > 
> > Signed-off-by: Kent Overstreet <koverstreet google com>
> > Change-Id: I5eb66c1d6910757f4af8755b8857dcbe4619cf8d
> 
> Please drop Change-ID tag and it would be great how you tested the
> changes, other than that,
> 
>  Acked-by: Tejun Heo <tj kernel org>

To add a bit here too.  Please explain "why" you're making this
change.  Is it because bi_destructor interface is cumbersome?  Adding
bi_pool is overhead - why is it justified?  Is it because one pointer
is fine to add to struct bio (which I kinda agree) or are there future
changes which will reverse the overhead (which is the case here).

In general, I find the descriptions insufficient.  They don't describe
the reasons and reasoning behind the patch.

Thanks.

-- 
tejun