Messages in this thread | | | Subject | Re: [PATCH V10 09/19] block: introduce bio_bvecs() | From | Sagi Grimberg <> | Date | Tue, 20 Nov 2018 19:20:45 -0800 |
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> Not sure I understand the 'blocking' problem in this case. > > We can build a bvec table from this req, and send them all > in send(),
I would like to avoid growing bvec tables and keep everything preallocated. Plus, a bvec_iter operates on a bvec which means we'll need a table there as well... Not liking it so far...
> can this way avoid your blocking issue? You may see this > example in branch 'rq->bio != rq->biotail' of lo_rw_aio().
This is exactly an example of not ignoring the bios...
> If this way is what you need, I think you are right, even we may > introduce the following helpers: > > rq_for_each_bvec() > rq_bvecs()
I'm not sure how this helps me either. Unless we can set a bvec_iter to span bvecs or have an abstract bio crossing when we re-initialize the bvec_iter I don't see how I can ignore bios completely...
> So looks nvme-tcp host driver might be the 2nd driver which benefits > from multi-page bvec directly. > > The multi-page bvec V11 has passed my tests and addressed almost > all the comments during review on V10. I removed bio_vecs() in V11, > but it won't be big deal, we can introduce them anytime when there > is the requirement.
multipage-bvecs and nvme-tcp are going to conflict, so it would be good to coordinate on this. I think that nvme-tcp host needs some adjustments as setting a bvec_iter. I'm under the impression that the change is rather small and self-contained, but I'm not sure I have the full picture here.
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