Return-Path: Received: from mail-pg1-f196.google.com ([209.85.215.196]:36526 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727200AbeKPMGy (ORCPT ); Fri, 16 Nov 2018 07:06:54 -0500 Received: by mail-pg1-f196.google.com with SMTP id n2so2679802pgm.3 for ; Thu, 15 Nov 2018 17:56:29 -0800 (PST) Date: Thu, 15 Nov 2018 17:56:27 -0800 From: Omar Sandoval To: Ming Lei Cc: Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Kent Overstreet , Mike Snitzer , dm-devel@redhat.com, Alexander Viro , linux-fsdevel@vger.kernel.org, Shaohua Li , linux-raid@vger.kernel.org, linux-erofs@lists.ozlabs.org, David Sterba , linux-btrfs@vger.kernel.org, "Darrick J . Wong" , linux-xfs@vger.kernel.org, Gao Xiang , Christoph Hellwig , Theodore Ts'o , linux-ext4@vger.kernel.org, Coly Li , linux-bcache@vger.kernel.org, Boaz Harrosh , Bob Peterson , cluster-devel@redhat.com Subject: Re: [PATCH V10 14/19] block: enable multipage bvecs Message-ID: <20181116015627.GI23828@vader> References: <20181115085306.9910-1-ming.lei@redhat.com> <20181115085306.9910-15-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181115085306.9910-15-ming.lei@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: 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 > Cc: Kent Overstreet > Cc: Mike Snitzer > Cc: dm-devel@redhat.com > Cc: Alexander Viro > Cc: linux-fsdevel@vger.kernel.org > Cc: Shaohua Li > Cc: linux-raid@vger.kernel.org > Cc: linux-erofs@lists.ozlabs.org > Cc: David Sterba > Cc: linux-btrfs@vger.kernel.org > Cc: Darrick J. Wong > Cc: linux-xfs@vger.kernel.org > Cc: Gao Xiang > Cc: Christoph Hellwig > Cc: Theodore Ts'o > Cc: linux-ext4@vger.kernel.org > Cc: Coly Li > Cc: linux-bcache@vger.kernel.org > Cc: Boaz Harrosh > Cc: Bob Peterson > Cc: cluster-devel@redhat.com > Signed-off-by: Ming Lei > --- > 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? > @@ -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? > + > + 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. > + return false; > + merge: > + bv->bv_len += len; > + bio->bi_iter.bi_size += len; > + return true; > } > return false; > } > -- > 2.9.5 >