On Tue, Sep 24, 2013 at 04:00:12AM -0700, Christoph Hellwig wrote: > Just curious, what's the state of the remaining immutable bio work? Mostly just waiting for Jens to pull it, though I did discover an issue with the "generic bio chaining" patch last time I was testing it - but that's towards the end of the series and the rest could be pulled now. Going to work on the series more today - the reworked segment merging patches is what lets us shrink struct bio; those patches aren't ready yet (and they're more invasive than some other cleanup I was planning on getting in first) but I think they're logically independent from most of the other patches, I'll see if I can mail out a short series on top of this one for you to look at. > > On Thu, Aug 08, 2013 at 02:15:29PM -0700, Kent Overstreet wrote: > > > What is preventing you from sending those out as well? While it's not > > > absolutely nessecary it would certainly be good if we'd avoid a struct > > > bio size regression. > > > > There's still some fairly significant changes, and I don't want to make > > too many invasive changes at once. > > > > Main thing is making generic_make_request() take arbitrary size bios. > > After this series that's just two simple patches, but then the changes > > to make use of that will be changing behaviour in non obvious ways. > > > > The way the merging changes work is it enables multi page bvecs - so a > > bvec can point to many physically contiguous pages. This moves segment > > merging to bio_add_page(), and gets rid of bi_phys_segments - now > > bi_vcnt == bi_phys_segments, we just split the bio if it's too big. > > > > Then, with bio_add_page() building up large bios and the block layer > > splitting them as necessary, there shouldn't be any need for segment > > merging across bios anymore (because generally when that would've > > happened before, now we'd just be sending one larger bio down). > > > > The remaining patches aren't terribly complicated though (less > > complicated than this patch series). Trickiest bit is multipage bvecs, > > and that's mostly just lots of code auditing - the way I convert > > existing code is by adding bio_for_each_page() - analagous to > > bio_for_each_segment, but giving you bvecs that point to single pages. > > So it's an easy conversion, just have to make sure nothing's missed. > ---end quoted text--- -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
