[Drbd-dev] [PATCH 07/10] block: kill merge_bvec_fn() completely

[Ming Lin]

On Tue, Apr 28, 2015 at 10:31 AM, Alasdair G Kergon <agk at redhat.com> wrote:
> On Mon, Apr 27, 2015 at 11:48:34PM -0700, Ming Lin wrote:
>> As generic_make_request() is now able to handle arbitrarily sized bios,
>> it's no longer necessary for each individual block driver to define its
>> own ->merge_bvec_fn() callback. Remove every invocation completely.
>
> merge_bvec_fn is also about telling the code building up bios what optimum
> maximum size to use.
>
> Have you got some test data to demonstrate that we won't find some situations
> where performance is now lost by code building up bios that are far too big
> and are always going to have to be split up later?

Not yet.
Fengguang will help to run some tests.

Thanks.

>
> Alasdair
>