Messages in this thread | | | From | "Huang\, Ying" <> | Subject | Re: [PATCH V10 15/19] block: always define BIO_MAX_PAGES as 256 | Date | Tue, 20 Nov 2018 10:45:03 +0800 |
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Ming Lei <ming.lei@redhat.com> 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
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