Re: [Cluster-devel] [PATCH V10 15/19] block: always define BIO_MAX_PAGES as 256
Ming Lei 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
Re: [Cluster-devel] [PATCH V10 15/19] block: always define BIO_MAX_PAGES as 256
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. thanks, Ming
Re: [Cluster-devel] [PATCH V10 15/19] block: always define BIO_MAX_PAGES as 256
> diff --git a/include/linux/bio.h b/include/linux/bio.h > index 5040e9a2eb09..277921ad42e7 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -34,15 +34,7 @@ > #define BIO_BUG_ON > #endif > > -#ifdef CONFIG_THP_SWAP > -#if HPAGE_PMD_NR > 256 > -#define BIO_MAX_PAGESHPAGE_PMD_NR > -#else > #define BIO_MAX_PAGES256 > -#endif > -#else > -#define BIO_MAX_PAGES256 > -#endif Looks good. This mess should have never gone in. Reviewed-by: Christoph Hellwig
Re: [Cluster-devel] [PATCH V10 15/19] block: always define BIO_MAX_PAGES as 256
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? > Cc: Dave Chinner > Cc: Kent Overstreet > Cc: Mike Snitzer > Cc: dm-de...@redhat.com > Cc: Alexander Viro > Cc: linux-fsde...@vger.kernel.org > Cc: Shaohua Li > Cc: linux-r...@vger.kernel.org > Cc: linux-er...@lists.ozlabs.org > Cc: David Sterba > Cc: linux-bt...@vger.kernel.org > Cc: Darrick J. Wong > Cc: linux-...@vger.kernel.org > Cc: Gao Xiang > Cc: Christoph Hellwig > Cc: Theodore Ts'o > Cc: linux-e...@vger.kernel.org > Cc: Coly Li > Cc: linux-bca...@vger.kernel.org > Cc: Boaz Harrosh > Cc: Bob Peterson > Cc: cluster-devel@redhat.com > Signed-off-by: Ming Lei > --- > include/linux/bio.h | 8 > 1 file changed, 8 deletions(-) > > diff --git a/include/linux/bio.h b/include/linux/bio.h > index 5040e9a2eb09..277921ad42e7 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -34,15 +34,7 @@ > #define BIO_BUG_ON > #endif > > -#ifdef CONFIG_THP_SWAP > -#if HPAGE_PMD_NR > 256 > -#define BIO_MAX_PAGESHPAGE_PMD_NR > -#else > #define BIO_MAX_PAGES256 > -#endif > -#else > -#define BIO_MAX_PAGES256 > -#endif > > #define bio_prio(bio)(bio)->bi_ioprio > #define bio_set_prio(bio, prio) ((bio)->bi_ioprio = prio) > -- > 2.9.5 >
