Messages in this thread | | | Date | Mon, 19 Nov 2018 16:45:23 +0800 | From | Ming Lei <> | Subject | Re: [PATCH V10 14/19] block: enable multipage bvecs |
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On Thu, Nov 15, 2018 at 05:56:27PM -0800, Omar Sandoval wrote: > On Thu, Nov 15, 2018 at 04:53:01PM +0800, Ming Lei wrote: > > This patch pulls the trigger for multi-page bvecs. > > > > Now any request queue which supports queue cluster will see multi-page > > bvecs. > > > > Cc: Dave Chinner <dchinner@redhat.com> > > Cc: Kent Overstreet <kent.overstreet@gmail.com> > > Cc: Mike Snitzer <snitzer@redhat.com> > > Cc: dm-devel@redhat.com > > Cc: Alexander Viro <viro@zeniv.linux.org.uk> > > Cc: linux-fsdevel@vger.kernel.org > > Cc: Shaohua Li <shli@kernel.org> > > Cc: linux-raid@vger.kernel.org > > Cc: linux-erofs@lists.ozlabs.org > > Cc: David Sterba <dsterba@suse.com> > > Cc: linux-btrfs@vger.kernel.org > > Cc: Darrick J. Wong <darrick.wong@oracle.com> > > Cc: linux-xfs@vger.kernel.org > > Cc: Gao Xiang <gaoxiang25@huawei.com> > > Cc: Christoph Hellwig <hch@lst.de> > > Cc: Theodore Ts'o <tytso@mit.edu> > > Cc: linux-ext4@vger.kernel.org > > Cc: Coly Li <colyli@suse.de> > > Cc: linux-bcache@vger.kernel.org > > Cc: Boaz Harrosh <ooo@electrozaur.com> > > Cc: Bob Peterson <rpeterso@redhat.com> > > Cc: cluster-devel@redhat.com > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > > --- > > block/bio.c | 24 ++++++++++++++++++------ > > 1 file changed, 18 insertions(+), 6 deletions(-) > > > > diff --git a/block/bio.c b/block/bio.c > > index 6486722d4d4b..ed6df6f8e63d 100644 > > --- a/block/bio.c > > +++ b/block/bio.c > > This comment above __bio_try_merge_page() doesn't make sense after this > change: > > This is a > a useful optimisation for file systems with a block size smaller than the > page size. > > Can you please get rid of it in this patch?
I understand __bio_try_merge_page() still works for original cases, so looks the optimization for sub-pagesize is still there too, isn't it?
> > > @@ -767,12 +767,24 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page, > > > > if (bio->bi_vcnt > 0) { > > struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; > > - > > - if (page == bv->bv_page && off == bv->bv_offset + bv->bv_len) { > > - bv->bv_len += len; > > - bio->bi_iter.bi_size += len; > > - return true; > > - } > > + struct request_queue *q = NULL; > > + > > + if (page == bv->bv_page && off == (bv->bv_offset + bv->bv_len) > > + && (off + len) <= PAGE_SIZE) > > + goto merge; > > The parentheses around (bv->bv_offset + bv->bv_len) and (off + len) are > unnecessary noise. > > What's the point of the new (off + len) <= PAGE_SIZE check?
Yeah, I don't know why I did it, :-(, the check is absolutely always true.
> > > + > > + if (bio->bi_disk) > > + q = bio->bi_disk->queue; > > + > > + /* disable multi-page bvec too if cluster isn't enabled */ > > + if (!q || !blk_queue_cluster(q) || > > + ((page_to_phys(bv->bv_page) + bv->bv_offset + bv->bv_len) != > > + (page_to_phys(page) + off))) > > More unnecessary parentheses here.
OK.
Thanks, Ming
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