On 5/27/18 1:23 AM, Ming Lei wrote: > On Fri, May 25, 2018 at 10:30:46AM -0600, Jens Axboe wrote: >> On 5/24/18 10:53 PM, Kent Overstreet wrote: >>> On Fri, May 25, 2018 at 11:45:48AM +0800, Ming Lei wrote: >>>> Hi, >>>> >>>> This patchset brings multipage bvec into block layer: >>> >>> patch series looks sane to me. goddamn that's a lot of renaming. >> >> Indeed... I actually objected to some of the segment -> page >> renaming, but it's still in there. The foo2() temporary functions >> also concern me, we all know there's nothing more permanent than a >> temporary fixup. > > Jens, I remember I explained the renaming story to you in lsfmm a bit: > > 1) the current naming of segment is actually wrong, since every segment > only stores one single-page vector > > 2) the most important part is that once multipage bvec is introduced, > if the old _segment naming is still kept, it can be very confusing, > especially no good name is left for the helpers of dealing with real > segment.
Yes, we discussed exactly this, which is why I'm surprised you went ahead with the same approach. I told you I don't like tree wide renames, if they can be avoided. I'd rather suffer some pain wrt page vs segments naming, and then later do a rename (if it bothers us) once the dust has settled on the interesting part of the changes. I'm very well away of our current naming and what it signifies. With #1, you are really splitting hairs, imho. Find a decent name for multiple segment. Chunk? > For the foo2() temporary change, that is only for avoiding tree-wide > change in one single tree, with this way, we can change sub-system one > by one, but if you think it is good to do tree-wide conversion in one > patch, I am fine to do it in next version. It's still a painful middle step. >>> Things are going to get interesting when we start sticking compound >>> pages in the page cache, there'll be some interesting questions of >>> semantics to deal with then but I think getting this will only help >>> w.r.t. plumbing that through and not dealing with 4k pages >>> unnecessarily - but I think even if we were to decide that merging >>> in bio_add_page() is not the way to go when the upper layers are >>> passing compound pages around already, this patch series helps >>> because regardless at some point everything under >>> generic_make_request() is going to have to deal with segments that >>> are more than one page, and this patch series makes that happen. So >>> incremental progress. >>> >>> Jens, any objections to getting this in? >> >> I like most of it, but I'd much rather get this way earlier in the >> series. We're basically just one week away from the merge window, it >> needs more simmer and testing time than that. On top of that, it >> hasn't received much review yet. >> >> So as far as I'm concerned, we can kick off the 4.19 block branch >> with iterated versions of this patchset. > > OK, I will post out again once v4.19 is started. Sounds good. -- Jens Axboe
