From: Keith Busch <kbusch@fb.com>
To: <linux-fsdevel@vger.kernel.org>, <linux-block@vger.kernel.org>,
<linux-nvme@lists.infradead.org>
Cc: <axboe@kernel.dk>, Kernel Team <Kernel-team@fb.com>, <hch@lst.de>,
<bvanassche@acm.org>, <damien.lemoal@opensource.wdc.com>,
<ebiggers@kernel.org>, <pankydev8@gmail.com>,
Keith Busch <kbusch@kernel.org>
Subject: [PATCHv5 06/11] block/merge: count bytes instead of sectors
Date: Tue, 31 May 2022 12:11:32 -0700 [thread overview]
Message-ID: <20220531191137.2291467-7-kbusch@fb.com> (raw)
In-Reply-To: <20220531191137.2291467-1-kbusch@fb.com>
From: Keith Busch <kbusch@kernel.org>
Individual bv_len's may not be a sector size.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
v4->v5:
Updated comment (Christoph)
block/blk-merge.c | 41 ++++++++++++++++++++++++-----------------
1 file changed, 24 insertions(+), 17 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 7771dacc99cb..21fb4d14ca3e 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -201,11 +201,11 @@ static inline unsigned get_max_segment_size(const struct request_queue *q,
* @nsegs: [in,out] Number of segments in the bio being built. Incremented
* by the number of segments from @bv that may be appended to that
* bio without exceeding @max_segs
- * @sectors: [in,out] Number of sectors in the bio being built. Incremented
- * by the number of sectors from @bv that may be appended to that
- * bio without exceeding @max_sectors
+ * @bytes: [in,out] Number of bytes in the bio being built. Incremented
+ * by the number of bytes from @bv that may be appended to that
+ * bio without exceeding @max_bytes
* @max_segs: [in] upper bound for *@nsegs
- * @max_sectors: [in] upper bound for *@sectors
+ * @max_bytes: [in] upper bound for *@bytes
*
* When splitting a bio, it can happen that a bvec is encountered that is too
* big to fit in a single segment and hence that it has to be split in the
@@ -216,10 +216,10 @@ static inline unsigned get_max_segment_size(const struct request_queue *q,
*/
static bool bvec_split_segs(const struct request_queue *q,
const struct bio_vec *bv, unsigned *nsegs,
- unsigned *sectors, unsigned max_segs,
- unsigned max_sectors)
+ unsigned *bytes, unsigned max_segs,
+ unsigned max_bytes)
{
- unsigned max_len = (min(max_sectors, UINT_MAX >> 9) - *sectors) << 9;
+ unsigned max_len = min(max_bytes, UINT_MAX) - *bytes;
unsigned len = min(bv->bv_len, max_len);
unsigned total_len = 0;
unsigned seg_size = 0;
@@ -237,7 +237,7 @@ static bool bvec_split_segs(const struct request_queue *q,
break;
}
- *sectors += total_len >> 9;
+ *bytes += total_len;
/* tell the caller to split the bvec if it is too big to fit */
return len > 0 || bv->bv_len > max_len;
@@ -269,8 +269,8 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
{
struct bio_vec bv, bvprv, *bvprvp = NULL;
struct bvec_iter iter;
- unsigned nsegs = 0, sectors = 0;
- const unsigned max_sectors = get_max_io_size(q, bio);
+ unsigned nsegs = 0, bytes = 0;
+ const unsigned max_bytes = get_max_io_size(q, bio) << 9;
const unsigned max_segs = queue_max_segments(q);
bio_for_each_bvec(bv, bio, iter) {
@@ -282,12 +282,12 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
goto split;
if (nsegs < max_segs &&
- sectors + (bv.bv_len >> 9) <= max_sectors &&
+ bytes + bv.bv_len <= max_bytes &&
bv.bv_offset + bv.bv_len <= PAGE_SIZE) {
nsegs++;
- sectors += bv.bv_len >> 9;
- } else if (bvec_split_segs(q, &bv, &nsegs, §ors, max_segs,
- max_sectors)) {
+ bytes += bv.bv_len;
+ } else if (bvec_split_segs(q, &bv, &nsegs, &bytes, max_segs,
+ max_bytes)) {
goto split;
}
@@ -300,13 +300,20 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
split:
*segs = nsegs;
+ /*
+ * Individual bvecs may not be logical block aligned. Round down the
+ * split size so that each bio is properly sector size aligned, even if
+ * we do not use the full hardware limits.
+ */
+ bytes = ALIGN_DOWN(bytes, queue_logical_block_size(q));
+
/*
* Bio splitting may cause subtle trouble such as hang when doing sync
* iopoll in direct IO routine. Given performance gain of iopoll for
* big IO can be trival, disable iopoll when split needed.
*/
bio_clear_polled(bio);
- return bio_split(bio, sectors, GFP_NOIO, bs);
+ return bio_split(bio, bytes >> SECTOR_SHIFT, GFP_NOIO, bs);
}
/**
@@ -375,7 +382,7 @@ EXPORT_SYMBOL(blk_queue_split);
unsigned int blk_recalc_rq_segments(struct request *rq)
{
unsigned int nr_phys_segs = 0;
- unsigned int nr_sectors = 0;
+ unsigned int bytes = 0;
struct req_iterator iter;
struct bio_vec bv;
@@ -398,7 +405,7 @@ unsigned int blk_recalc_rq_segments(struct request *rq)
}
rq_for_each_bvec(bv, rq, iter)
- bvec_split_segs(rq->q, &bv, &nr_phys_segs, &nr_sectors,
+ bvec_split_segs(rq->q, &bv, &nr_phys_segs, &bytes,
UINT_MAX, UINT_MAX);
return nr_phys_segs;
}
--
2.30.2
next prev parent reply other threads:[~2022-05-31 19:17 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-31 19:11 [PATCHv5 00/11] direct-io dma alignment Keith Busch
2022-05-31 19:11 ` [PATCHv5 01/11] block: fix infinite loop for invalid zone append Keith Busch
2022-06-01 8:03 ` Johannes Thumshirn
2022-05-31 19:11 ` [PATCHv5 02/11] block/bio: remove duplicate append pages code Keith Busch
2022-05-31 19:11 ` [PATCHv5 03/11] block: export dma_alignment attribute Keith Busch
2022-05-31 19:11 ` [PATCHv5 04/11] block: introduce bdev_dma_alignment helper Keith Busch
2022-05-31 19:11 ` [PATCHv5 05/11] block: add a helper function for dio alignment Keith Busch
2022-06-01 5:29 ` Christoph Hellwig
2022-06-01 8:04 ` Johannes Thumshirn
2022-05-31 19:11 ` Keith Busch [this message]
2022-06-01 8:05 ` [PATCHv5 06/11] block/merge: count bytes instead of sectors Johannes Thumshirn
2022-05-31 19:11 ` [PATCHv5 08/11] iov: introduce iov_iter_aligned Keith Busch
2022-06-01 5:30 ` Christoph Hellwig
2022-05-31 19:11 ` [PATCHv5 09/11] block: introduce bdev_iter_is_aligned helper Keith Busch
2022-05-31 21:46 ` Eric Biggers
2022-06-01 5:31 ` Christoph Hellwig
2022-05-31 19:11 ` [PATCHv5 10/11] block: relax direct io memory alignment Keith Busch
2022-06-01 5:31 ` Christoph Hellwig
2022-05-31 19:11 ` [PATCHv5 11/11] fs: add support for dma aligned direct-io Keith Busch
2022-06-01 5:32 ` Christoph Hellwig
[not found] ` <20220531191137.2291467-8-kbusch@fb.com>
2022-06-01 7:04 ` [PATCHv5 07/11] block/bounce: count bytes instead of sectors Eric Biggers
2022-06-01 7:11 ` [PATCHv5 00/11] direct-io dma alignment Eric Biggers
2022-06-01 14:28 ` Keith Busch
2022-06-01 16:12 ` Keith Busch
2022-06-06 16:24 ` Keith Busch
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