[PATCH V10 15/19] block: always define BIO_MAX_PAGES as 256

Omar Sandoval osandov at osandov.com
Fri Nov 16 12:59:36 AEDT 2018


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 <dchinner at redhat.com>
> Cc: Kent Overstreet <kent.overstreet at gmail.com>
> Cc: Mike Snitzer <snitzer at redhat.com>
> Cc: dm-devel at redhat.com
> Cc: Alexander Viro <viro at zeniv.linux.org.uk>
> Cc: linux-fsdevel at vger.kernel.org
> Cc: Shaohua Li <shli at kernel.org>
> Cc: linux-raid at vger.kernel.org
> Cc: linux-erofs at lists.ozlabs.org
> Cc: David Sterba <dsterba at suse.com>
> Cc: linux-btrfs at vger.kernel.org
> Cc: Darrick J. Wong <darrick.wong at oracle.com>
> Cc: linux-xfs at vger.kernel.org
> Cc: Gao Xiang <gaoxiang25 at huawei.com>
> Cc: Christoph Hellwig <hch at lst.de>
> Cc: Theodore Ts'o <tytso at mit.edu>
> Cc: linux-ext4 at vger.kernel.org
> Cc: Coly Li <colyli at suse.de>
> Cc: linux-bcache at vger.kernel.org
> Cc: Boaz Harrosh <ooo at electrozaur.com>
> Cc: Bob Peterson <rpeterso at redhat.com>
> Cc: cluster-devel at redhat.com
> Signed-off-by: Ming Lei <ming.lei at redhat.com>
> ---
>  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_PAGES		HPAGE_PMD_NR
> -#else
>  #define BIO_MAX_PAGES		256
> -#endif
> -#else
> -#define BIO_MAX_PAGES		256
> -#endif
>  
>  #define bio_prio(bio)			(bio)->bi_ioprio
>  #define bio_set_prio(bio, prio)		((bio)->bi_ioprio = prio)
> -- 
> 2.9.5
> 


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