On 2/27/19 8:24 PM, Ming Lei wrote: > bio_for_each_bvec is used in fast path of bio splitting and sg mapping, > and what we want to do is to iterate over multi-page bvecs, instead of pages. > However, bvec_iter_advance() is invisble for this requirement, and > always advance by page size. > > This way isn't efficient for multipage bvec iterator, also bvec_iter_len() > isn't as fast as mp_bvec_iter_len(). > > So advance by multi-page bvec's length instead of page size for > bio_for_each_bvec(). > > More than 1% IOPS improvement can be observed in io_uring test on null_blk.
Thanks Ming, I tested this last night with good results. -- Jens Axboe
