Ming Lei <ming.lei@xxxxxxxxxx> writes: > On Thu, Nov 15, 2018 at 05:59:36PM -0800, Omar Sandoval wrote: >> On Thu, Nov 15, 2018 at 04:53:02PM +0800, Ming Lei wrote: >> > Now multi-page bvec can cover CONFIG_THP_SWAP, so we don't need to >> > increase BIO_MAX_PAGES for it. >> >> You mentioned to it in the cover letter, but this needs more explanation >> in the commit message. Why did CONFIG_THP_SWAP require > 256? Why does >> multipage bvecs remove that requirement? > > CONFIG_THP_SWAP needs to split one TH page into normal pages and adds > them all to one bio. With multipage-bvec, it just takes one bvec to > hold them all. Yes. CONFIG_THP_SWAP needs to put 512 normal sub-pages into one bio to write the 512 sub-pages together. With the help of multipage-bvec, it needs just bvect to hold 512 normal sub-pages. Best Regards, Huang, Ying > thanks, > Ming
