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From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Ming Lei <ming.lei@redhat.com>,
	Omar Sandoval <osandov@fb.com>, Christoph Hellwig <hch@lst.de>
Subject: [PATCH V2 03/10] block: don't merge adjacent bvecs to one segment in bio blk_queue_split
Date: Sun, 17 Mar 2019 18:01:05 +0800	[thread overview]
Message-ID: <20190317100112.8106-4-ming.lei@redhat.com> (raw)
In-Reply-To: <20190317100112.8106-1-ming.lei@redhat.com>

For normal filesystem IO, each page is added via blk_add_page(),
in which bvec(page) merge has been handled already, and basically
not possible to merge two adjacent bvecs in one bio.

So not try to merge two adjacent bvecs in blk_queue_split().

Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-merge.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 1c9d4f0f96ea..aa9164eb7187 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -267,23 +267,6 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
 			goto split;
 		}
 
-		if (bvprvp) {
-			if (seg_size + bv.bv_len > queue_max_segment_size(q))
-				goto new_segment;
-			if (!biovec_phys_mergeable(q, bvprvp, &bv))
-				goto new_segment;
-
-			seg_size += bv.bv_len;
-			bvprv = bv;
-			bvprvp = &bvprv;
-			sectors += bv.bv_len >> 9;
-
-			if (nsegs == 1 && seg_size > front_seg_size)
-				front_seg_size = seg_size;
-
-			continue;
-		}
-new_segment:
 		if (nsegs == max_segs)
 			goto split;
 
-- 
2.9.5


  parent reply	other threads:[~2019-03-17 10:01 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-17 10:01 [PATCH V2 00/10] block: enable multi-page bvec for passthrough IO Ming Lei
2019-03-17 10:01 ` [PATCH V2 01/10] block: pass page to xen_biovec_phys_mergeable Ming Lei
2019-03-17 10:01 ` [PATCH V2 02/10] block: avoid to break XEN by multi-page bvec Ming Lei
2019-03-19  9:18   ` Juergen Gross
2019-03-17 10:01 ` Ming Lei [this message]
2019-03-17 10:01 ` [PATCH V2 04/10] block: cleanup bio_add_pc_page Ming Lei
2019-03-17 10:01 ` [PATCH V2 05/10] block: check if page is mergeable in one helper Ming Lei
2019-03-17 10:01 ` [PATCH V2 06/10] block: put the same page when adding it to bio Ming Lei
2019-03-17 10:01 ` [PATCH V2 07/10] block: enable multi-page bvec for passthrough IO Ming Lei
2019-03-17 10:01 ` [PATCH V2 08/10] block: remove argument of 'request_queue' from __blk_bvec_map_sg Ming Lei
2019-03-17 10:01 ` [PATCH V2 09/10] block: reuse __blk_bvec_map_sg() for mapping page sized bvec Ming Lei
2019-03-17 10:01 ` [PATCH V2 10/10] block: don't check if adjacent bvecs in one bio can be mergeable Ming Lei
2019-03-27 15:44 ` [PATCH V2 00/10] block: enable multi-page bvec for passthrough IO Jens Axboe

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