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* [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request
@ 2020-09-02 12:00 Xiao Ni
  2020-09-02 12:00 ` [PATCH V6 1/3] md: calculate discard start address and size in specific raid type Xiao Ni
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Xiao Ni @ 2020-09-02 12:00 UTC (permalink / raw)
  To: linux-raid, song; +Cc: heinzm, ncroxon, guoqing.jiang, colyli

Hi all

Now mkfs on raid10 which is combined with ssd/nvme disks takes a long time.
This patch set tries to resolve this problem.

v1:
Coly helps to review these patches and give some suggestions:
One bug is found. If discard bio is across one stripe but bio size is
bigger than one stripe size. After spliting, the bio will be NULL.
In this version, it checks whether discard bio size is bigger than
(2*stripe_size). 
In raid10_end_discard_request, it's better to check R10BIO_Uptodate
is set or not. It can avoid write memory to improve performance. 
Add more comments for calculating addresses.

v2:
Fix error by checkpatch.pl
Fix one bug for offset layout. v1 calculates wrongly split size
Add more comments to explain how the discard range of each component disk
is decided.

v3:
add support for far layout
Change the patch name

v4:
Pull codes that wait for blocked device into a seprate function
It can't use (stripe_size-1) as a mask to calculate. (stripe_size-1) may
not be power of 2.
It doesn't need to use a full copy of geo.
Fix warning by checkpatch.pl

v5:
In 32bit platform, it doesn't support 64bit devide by 32bit value.
Reported-by: kernel test robot <lkp@intel.com>

v6:
Move the codes that calculate discard start/size into specific raid type.
Remove discard support for reshape

Xiao Ni (3):
  md: calculate discard start address and size in specific raid type
  md/raid10: improve raid10 discard request
  md/raid10: improve discard request for far layout

 drivers/md/md.c     |   9 +-
 drivers/md/md.h     |   3 +-
 drivers/md/raid0.c  |   5 +-
 drivers/md/raid10.c | 296 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 drivers/md/raid10.h |   1 +
 5 files changed, 303 insertions(+), 11 deletions(-)

-- 
2.7.5


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH V6 1/3] md: calculate discard start address and size in specific raid type
  2020-09-02 12:00 [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request Xiao Ni
@ 2020-09-02 12:00 ` Xiao Ni
  2020-09-02 12:00 ` [PATCH V6 2/3] md/raid10: improve raid10 discard request Xiao Ni
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Xiao Ni @ 2020-09-02 12:00 UTC (permalink / raw)
  To: linux-raid, song; +Cc: heinzm, ncroxon, guoqing.jiang, colyli

For raid10 it needs to choose new data offset and old offset
in reshape. So it's better to calculate discard start address
and size in specific raid type.

Signed-off-by: Xiao Ni <xni@redhat.com>
---
 drivers/md/md.c    | 9 +++------
 drivers/md/md.h    | 3 +--
 drivers/md/raid0.c | 5 +++--
 3 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 10743be..e360d46 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8585,15 +8585,12 @@ EXPORT_SYMBOL(md_write_end);
 
 /* This is used by raid0 and raid10 */
 void md_submit_discard_bio(struct mddev *mddev, struct md_rdev *rdev,
-				struct bio *bio,
-				sector_t dev_start, sector_t dev_end)
+			struct bio *bio, sector_t start, sector_t size)
 {
 	struct bio *discard_bio = NULL;
 
-	if (__blkdev_issue_discard(rdev->bdev,
-	    dev_start + rdev->data_offset,
-	    dev_end - dev_start, GFP_NOIO, 0, &discard_bio) ||
-	    !discard_bio)
+	if (__blkdev_issue_discard(rdev->bdev, start, size,
+		GFP_NOIO, 0, &discard_bio) || !discard_bio)
 		return;
 
 	bio_chain(discard_bio, bio);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index bae3bd5..da9997a 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -714,8 +714,7 @@ extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
 extern void md_finish_reshape(struct mddev *mddev);
 extern void md_submit_discard_bio(struct mddev *mddev, struct md_rdev *rdev,
-				struct bio *bio,
-				sector_t dev_start, sector_t dev_end);
+			struct bio *bio, sector_t start, sector_t size);
 
 extern bool __must_check md_flush_request(struct mddev *mddev, struct bio *bio);
 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 2868294..d3da17b 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -532,8 +532,9 @@ static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
 
 		rdev = conf->devlist[(zone - conf->strip_zone) *
 			conf->strip_zone[0].nb_dev + disk];
-		dev_start += zone->dev_start;
-		md_submit_discard_bio(mddev, rdev, bio, dev_start, dev_end);
+		md_submit_discard_bio(mddev, rdev, bio,
+			dev_start + zone->dev_start + rdev->data_offset,
+			dev_end - dev_start);
 	}
 	bio_endio(bio);
 }
-- 
2.7.5


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH V6 2/3] md/raid10: improve raid10 discard request
  2020-09-02 12:00 [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request Xiao Ni
  2020-09-02 12:00 ` [PATCH V6 1/3] md: calculate discard start address and size in specific raid type Xiao Ni
@ 2020-09-02 12:00 ` Xiao Ni
  2020-09-02 12:00 ` [PATCH V6 3/3] md/raid10: improve discard request for far layout Xiao Ni
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Xiao Ni @ 2020-09-02 12:00 UTC (permalink / raw)
  To: linux-raid, song; +Cc: heinzm, ncroxon, guoqing.jiang, colyli

Now the discard request is split by chunk size. So it takes a long time
to finish mkfs on disks which support discard function. This patch improve
handling raid10 discard request. It uses the similar way with patch
29efc390b (md/md0: optimize raid0 discard handling).

But it's a little complex than raid0. Because raid10 has different layout.
If raid10 is offset layout and the discard request is smaller than stripe
size. There are some holes when we submit discard bio to underlayer disks.

For example: five disks (disk1 - disk5)
D01 D02 D03 D04 D05
D05 D01 D02 D03 D04
D06 D07 D08 D09 D10
D10 D06 D07 D08 D09
The discard bio just wants to discard from D03 to D10. For disk3, there is
a hole between D03 and D08. For disk4, there is a hole between D04 and D09.
D03 is a chunk, raid10_write_request can handle one chunk perfectly. So
the part that is not aligned with stripe size is still handled by
raid10_write_request.

If reshape is running when discard bio comes and the discard bio spans the
reshape position, raid10_write_request is responsible to handle this
discard bio.

I did a test with this patch set.
Without patch:
time mkfs.xfs /dev/md0
real4m39.775s
user0m0.000s
sys0m0.298s

With patch:
time mkfs.xfs /dev/md0
real0m0.105s
user0m0.000s
sys0m0.007s

nvme3n1           259:1    0   477G  0 disk
└─nvme3n1p1       259:10   0    50G  0 part
nvme4n1           259:2    0   477G  0 disk
└─nvme4n1p1       259:11   0    50G  0 part
nvme5n1           259:6    0   477G  0 disk
└─nvme5n1p1       259:12   0    50G  0 part
nvme2n1           259:9    0   477G  0 disk
└─nvme2n1p1       259:15   0    50G  0 part
nvme0n1           259:13   0   477G  0 disk
└─nvme0n1p1       259:14   0    50G  0 part

Reviewed-by: Coly Li <colyli@suse.de>
Reviewed-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Xiao Ni <xni@redhat.com>
---
 drivers/md/raid10.c | 256 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 255 insertions(+), 1 deletion(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 05e7f8d..e619151 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1516,6 +1516,256 @@ static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
 		raid10_write_request(mddev, bio, r10_bio);
 }
 
+static struct bio *raid10_split_bio(struct r10conf *conf,
+			struct bio *bio, sector_t sectors, bool want_first)
+{
+	struct bio *split;
+
+	split = bio_split(bio, sectors,	GFP_NOIO, &conf->bio_split);
+	bio_chain(split, bio);
+	allow_barrier(conf);
+	if (want_first) {
+		submit_bio_noacct(bio);
+		bio = split;
+	} else
+		submit_bio_noacct(split);
+	wait_barrier(conf);
+
+	return bio;
+}
+
+static void raid10_end_discard_request(struct bio *bio)
+{
+	struct r10bio *r10_bio = bio->bi_private;
+	struct r10conf *conf = r10_bio->mddev->private;
+	struct md_rdev *rdev = NULL;
+	int dev;
+	int slot, repl;
+
+	/*
+	 * We don't care the return value of discard bio
+	 */
+	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
+		set_bit(R10BIO_Uptodate, &r10_bio->state);
+
+	dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
+	if (repl)
+		rdev = conf->mirrors[dev].replacement;
+	if (!rdev) {
+		/* raid10_remove_disk uses smp_mb to make sure rdev is set to
+		 * replacement before setting replacement to NULL. It can read
+		 * rdev first without barrier protect even replacment is NULL
+		 */
+		smp_rmb();
+		rdev = conf->mirrors[dev].rdev;
+	}
+
+	if (atomic_dec_and_test(&r10_bio->remaining)) {
+		md_write_end(r10_bio->mddev);
+		raid_end_bio_io(r10_bio);
+	}
+
+	rdev_dec_pending(rdev, conf->mddev);
+}
+
+/* There are some limitations to handle discard bio
+ * 1st, the discard size is bigger than stripe_size*2.
+ * 2st, if the discard bio spans reshape progress, we use the old way to
+ * handle discard bio
+ */
+static bool raid10_handle_discard(struct mddev *mddev, struct bio *bio)
+{
+	struct r10conf *conf = mddev->private;
+	struct geom *geo = &conf->geo;
+	struct r10bio *r10_bio;
+
+	int disk;
+	sector_t chunk;
+	unsigned int stripe_size;
+	sector_t split_size;
+
+	sector_t bio_start, bio_end;
+	sector_t first_stripe_index, last_stripe_index;
+	sector_t start_disk_offset;
+	unsigned int start_disk_index;
+	sector_t end_disk_offset;
+	unsigned int end_disk_index;
+	unsigned int remainder;
+
+	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+		return -EAGAIN;
+
+	wait_barrier(conf);
+
+	/* Check reshape again to avoid reshape happens after checking
+	 * MD_RECOVERY_RESHAPE and before wait_barrier
+	 */
+	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+		goto out;
+
+	stripe_size = geo->raid_disks << geo->chunk_shift;
+	bio_start = bio->bi_iter.bi_sector;
+	bio_end = bio_end_sector(bio);
+
+	/* Maybe one discard bio is smaller than strip size or across one stripe
+	 * and discard region is larger than one stripe size. For far offset layout,
+	 * if the discard region is not aligned with stripe size, there is hole
+	 * when we submit discard bio to member disk. For simplicity, we only
+	 * handle discard bio which discard region is bigger than stripe_size*2
+	 */
+	if (bio_sectors(bio) < stripe_size*2)
+		goto out;
+
+	/* For far offset layout, if bio is not aligned with stripe size, it splits
+	 * the part that is not aligned with strip size.
+	 */
+	div_u64_rem(bio_start, stripe_size, &remainder);
+	if (geo->far_offset && remainder) {
+		split_size = stripe_size - remainder;
+		bio = raid10_split_bio(conf, bio, split_size, false);
+	}
+	div_u64_rem(bio_end, stripe_size, &remainder);
+	if (geo->far_offset && remainder) {
+		split_size = bio_sectors(bio) - remainder;
+		bio = raid10_split_bio(conf, bio, split_size, true);
+	}
+
+	r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
+	r10_bio->mddev = mddev;
+	r10_bio->state = 0;
+	r10_bio->sectors = 0;
+	memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks);
+
+	wait_blocked_dev(mddev, r10_bio);
+
+	r10_bio->master_bio = bio;
+
+	bio_start = bio->bi_iter.bi_sector;
+	bio_end = bio_end_sector(bio);
+
+	/* raid10 uses chunk as the unit to store data. It's similar like raid0.
+	 * One stripe contains the chunks from all member disk (one chunk from
+	 * one disk at the same HBA address). For layout detail, see 'man md 4'
+	 */
+	chunk = bio_start >> geo->chunk_shift;
+	chunk *= geo->near_copies;
+	first_stripe_index = chunk;
+	start_disk_index = sector_div(first_stripe_index, geo->raid_disks);
+	if (geo->far_offset)
+		first_stripe_index *= geo->far_copies;
+	start_disk_offset = (bio_start & geo->chunk_mask) +
+				(first_stripe_index << geo->chunk_shift);
+
+	chunk = bio_end >> geo->chunk_shift;
+	chunk *= geo->near_copies;
+	last_stripe_index = chunk;
+	end_disk_index = sector_div(last_stripe_index, geo->raid_disks);
+	if (geo->far_offset)
+		last_stripe_index *= geo->far_copies;
+	end_disk_offset = (bio_end & geo->chunk_mask) +
+				(last_stripe_index << geo->chunk_shift);
+
+	rcu_read_lock();
+	for (disk = 0; disk < geo->raid_disks; disk++) {
+		struct md_rdev *rdev = rcu_dereference(conf->mirrors[disk].rdev);
+		struct md_rdev *rrdev = rcu_dereference(
+			conf->mirrors[disk].replacement);
+
+		r10_bio->devs[disk].bio = NULL;
+		r10_bio->devs[disk].repl_bio = NULL;
+
+		if (rdev && (test_bit(Faulty, &rdev->flags)))
+			rdev = NULL;
+		if (rrdev && (test_bit(Faulty, &rrdev->flags)))
+			rrdev = NULL;
+		if (!rdev && !rrdev)
+			continue;
+
+		if (rdev) {
+			r10_bio->devs[disk].bio = bio;
+			atomic_inc(&rdev->nr_pending);
+		}
+		if (rrdev) {
+			r10_bio->devs[disk].repl_bio = bio;
+			atomic_inc(&rrdev->nr_pending);
+		}
+	}
+	rcu_read_unlock();
+
+	atomic_set(&r10_bio->remaining, 1);
+	for (disk = 0; disk < geo->raid_disks; disk++) {
+		sector_t dev_start, dev_end;
+		struct bio *mbio, *rbio = NULL;
+		struct md_rdev *rdev = rcu_dereference(conf->mirrors[disk].rdev);
+		struct md_rdev *rrdev = rcu_dereference(
+			conf->mirrors[disk].replacement);
+
+		/*
+		 * Now start to calculate the start and end address for each disk.
+		 * The space between dev_start and dev_end is the discard region.
+		 *
+		 * For dev_start, it needs to consider three conditions:
+		 * 1st, the disk is before start_disk, you can imagine the disk in
+		 * the next stripe. So the dev_start is the start address of next
+		 * stripe.
+		 * 2st, the disk is after start_disk, it means the disk is at the
+		 * same stripe of first disk
+		 * 3st, the first disk itself, we can use start_disk_offset directly
+		 */
+		if (disk < start_disk_index)
+			dev_start = (first_stripe_index + 1) * mddev->chunk_sectors;
+		else if (disk > start_disk_index)
+			dev_start = first_stripe_index * mddev->chunk_sectors;
+		else
+			dev_start = start_disk_offset;
+
+		if (disk < end_disk_index)
+			dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
+		else if (disk > end_disk_index)
+			dev_end = last_stripe_index * mddev->chunk_sectors;
+		else
+			dev_end = end_disk_offset;
+
+		/* It only handles discard bio which size is >= stripe size, so
+		 * dev_end > dev_start all the time
+		 */
+		if (r10_bio->devs[disk].bio) {
+			mbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
+			mbio->bi_end_io = raid10_end_discard_request;
+			mbio->bi_private = r10_bio;
+			r10_bio->devs[disk].bio = mbio;
+			r10_bio->devs[disk].devnum = disk;
+			atomic_inc(&r10_bio->remaining);
+			md_submit_discard_bio(mddev, rdev, mbio,
+					dev_start + choose_data_offset(r10_bio, rdev),
+					dev_end - dev_start);
+			bio_endio(mbio);
+		}
+		if (r10_bio->devs[disk].repl_bio) {
+			rbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
+			rbio->bi_end_io = raid10_end_discard_request;
+			rbio->bi_private = r10_bio;
+			r10_bio->devs[disk].repl_bio = rbio;
+			r10_bio->devs[disk].devnum = disk;
+			atomic_inc(&r10_bio->remaining);
+			md_submit_discard_bio(mddev, rrdev, rbio,
+					dev_start + choose_data_offset(r10_bio, rrdev),
+					dev_end - dev_start);
+			bio_endio(rbio);
+		}
+	}
+
+	if (atomic_dec_and_test(&r10_bio->remaining)) {
+		md_write_end(r10_bio->mddev);
+		raid_end_bio_io(r10_bio);
+	}
+
+	return 0;
+out:
+	allow_barrier(conf);
+	return -EAGAIN;
+}
+
 static bool raid10_make_request(struct mddev *mddev, struct bio *bio)
 {
 	struct r10conf *conf = mddev->private;
@@ -1530,6 +1780,10 @@ static bool raid10_make_request(struct mddev *mddev, struct bio *bio)
 	if (!md_write_start(mddev, bio))
 		return false;
 
+	if (unlikely(bio_op(bio) == REQ_OP_DISCARD))
+		if (!raid10_handle_discard(mddev, bio))
+			return true;
+
 	/*
 	 * If this request crosses a chunk boundary, we need to split
 	 * it.
@@ -3760,7 +4014,7 @@ static int raid10_run(struct mddev *mddev)
 	chunk_size = mddev->chunk_sectors << 9;
 	if (mddev->queue) {
 		blk_queue_max_discard_sectors(mddev->queue,
-					      mddev->chunk_sectors);
+					      UINT_MAX);
 		blk_queue_max_write_same_sectors(mddev->queue, 0);
 		blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
 		blk_queue_io_min(mddev->queue, chunk_size);
-- 
2.7.5


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH V6 3/3] md/raid10: improve discard request for far layout
  2020-09-02 12:00 [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request Xiao Ni
  2020-09-02 12:00 ` [PATCH V6 1/3] md: calculate discard start address and size in specific raid type Xiao Ni
  2020-09-02 12:00 ` [PATCH V6 2/3] md/raid10: improve raid10 discard request Xiao Ni
@ 2020-09-02 12:00 ` Xiao Ni
  2020-09-02 12:04 ` [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request Xiao Ni
  2020-09-15  6:29 ` Song Liu
  4 siblings, 0 replies; 6+ messages in thread
From: Xiao Ni @ 2020-09-02 12:00 UTC (permalink / raw)
  To: linux-raid, song; +Cc: heinzm, ncroxon, guoqing.jiang, colyli

For far layout, the discard region is not continuous on disks. So it needs
far copies r10bio to cover all regions. It needs a way to know all r10bios
have finish or not. Similar with raid10_sync_request, only the first r10bio
master_bio records the discard bio. Other r10bios master_bio record the
first r10bio. The first r10bio can finish after other r10bios finish and
then return the discard bio.

Signed-off-by: Xiao Ni <xni@redhat.com>
---
 drivers/md/raid10.c | 86 +++++++++++++++++++++++++++++++++++++++--------------
 drivers/md/raid10.h |  1 +
 2 files changed, 64 insertions(+), 23 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e619151..524344c 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1534,6 +1534,28 @@ static struct bio *raid10_split_bio(struct r10conf *conf,
 	return bio;
 }
 
+static void raid_end_discard_bio(struct r10bio *r10bio)
+{
+	struct r10conf *conf = r10bio->mddev->private;
+	struct r10bio *first_r10bio;
+
+	while (atomic_dec_and_test(&r10bio->remaining)) {
+
+		allow_barrier(conf);
+
+		if (!test_bit(R10BIO_Discard, &r10bio->state)) {
+			first_r10bio = (struct r10bio *)r10bio->master_bio;
+			free_r10bio(r10bio);
+			r10bio = first_r10bio;
+		} else {
+			md_write_end(r10bio->mddev);
+			bio_endio(r10bio->master_bio);
+			free_r10bio(r10bio);
+			break;
+		}
+	}
+}
+
 static void raid10_end_discard_request(struct bio *bio)
 {
 	struct r10bio *r10_bio = bio->bi_private;
@@ -1560,11 +1582,7 @@ static void raid10_end_discard_request(struct bio *bio)
 		rdev = conf->mirrors[dev].rdev;
 	}
 
-	if (atomic_dec_and_test(&r10_bio->remaining)) {
-		md_write_end(r10_bio->mddev);
-		raid_end_bio_io(r10_bio);
-	}
-
+	raid_end_discard_bio(r10_bio);
 	rdev_dec_pending(rdev, conf->mddev);
 }
 
@@ -1577,7 +1595,9 @@ static bool raid10_handle_discard(struct mddev *mddev, struct bio *bio)
 {
 	struct r10conf *conf = mddev->private;
 	struct geom *geo = &conf->geo;
-	struct r10bio *r10_bio;
+	struct r10bio *r10_bio, *first_r10bio;
+	int far_copies = geo->far_copies;
+	bool first_copy = true;
 
 	int disk;
 	sector_t chunk;
@@ -1616,30 +1636,20 @@ static bool raid10_handle_discard(struct mddev *mddev, struct bio *bio)
 	if (bio_sectors(bio) < stripe_size*2)
 		goto out;
 
-	/* For far offset layout, if bio is not aligned with stripe size, it splits
-	 * the part that is not aligned with strip size.
+	/* For far and far offset layout, if bio is not aligned with stripe size,
+	 * it splits the part that is not aligned with strip size.
 	 */
 	div_u64_rem(bio_start, stripe_size, &remainder);
-	if (geo->far_offset && remainder) {
+	if ((far_copies > 1) && remainder) {
 		split_size = stripe_size - remainder;
 		bio = raid10_split_bio(conf, bio, split_size, false);
 	}
 	div_u64_rem(bio_end, stripe_size, &remainder);
-	if (geo->far_offset && remainder) {
+	if ((far_copies > 1) && remainder) {
 		split_size = bio_sectors(bio) - remainder;
 		bio = raid10_split_bio(conf, bio, split_size, true);
 	}
 
-	r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
-	r10_bio->mddev = mddev;
-	r10_bio->state = 0;
-	r10_bio->sectors = 0;
-	memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks);
-
-	wait_blocked_dev(mddev, r10_bio);
-
-	r10_bio->master_bio = bio;
-
 	bio_start = bio->bi_iter.bi_sector;
 	bio_end = bio_end_sector(bio);
 
@@ -1665,6 +1675,28 @@ static bool raid10_handle_discard(struct mddev *mddev, struct bio *bio)
 	end_disk_offset = (bio_end & geo->chunk_mask) +
 				(last_stripe_index << geo->chunk_shift);
 
+retry_discard:
+	r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
+	r10_bio->mddev = mddev;
+	r10_bio->state = 0;
+	r10_bio->sectors = 0;
+	memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks);
+	wait_blocked_dev(mddev, r10_bio);
+
+	/* For far layout it needs more than one r10bio to cover all regions.
+	 * Inspired by raid10_sync_request, we can use the first r10bio->master_bio
+	 * to record the discard bio. Other r10bio->master_bio record the first
+	 * r10bio. The first r10bio only release after all other r10bios finish.
+	 * The discard bio returns only first r10bio finishes
+	 */
+	if (first_copy) {
+		r10_bio->master_bio = bio;
+		set_bit(R10BIO_Discard, &r10_bio->state);
+		first_copy = false;
+		first_r10bio = r10_bio;
+	} else
+		r10_bio->master_bio = (struct bio *)first_r10bio;
+
 	rcu_read_lock();
 	for (disk = 0; disk < geo->raid_disks; disk++) {
 		struct md_rdev *rdev = rcu_dereference(conf->mirrors[disk].rdev);
@@ -1755,11 +1787,19 @@ static bool raid10_handle_discard(struct mddev *mddev, struct bio *bio)
 		}
 	}
 
-	if (atomic_dec_and_test(&r10_bio->remaining)) {
-		md_write_end(r10_bio->mddev);
-		raid_end_bio_io(r10_bio);
+	if (!geo->far_offset && --far_copies) {
+		first_stripe_index += geo->stride >> geo->chunk_shift;
+		start_disk_offset += geo->stride;
+		last_stripe_index += geo->stride >> geo->chunk_shift;
+		end_disk_offset += geo->stride;
+		atomic_inc(&first_r10bio->remaining);
+		raid_end_discard_bio(r10_bio);
+		wait_barrier(conf);
+		goto retry_discard;
 	}
 
+	raid_end_discard_bio(r10_bio);
+
 	return 0;
 out:
 	allow_barrier(conf);
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index 79cd2b7..1461fd5 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -179,5 +179,6 @@ enum r10bio_state {
 	R10BIO_Previous,
 /* failfast devices did receive failfast requests. */
 	R10BIO_FailFast,
+	R10BIO_Discard,
 };
 #endif
-- 
2.7.5


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request
  2020-09-02 12:00 [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request Xiao Ni
                   ` (2 preceding siblings ...)
  2020-09-02 12:00 ` [PATCH V6 3/3] md/raid10: improve discard request for far layout Xiao Ni
@ 2020-09-02 12:04 ` Xiao Ni
  2020-09-15  6:29 ` Song Liu
  4 siblings, 0 replies; 6+ messages in thread
From: Xiao Ni @ 2020-09-02 12:04 UTC (permalink / raw)
  To: linux-raid, song; +Cc: heinzm, ncroxon, guoqing.jiang, colyli

Hi Song

I did test with reshape, it still has problems. So I remove discard 
support for reshape in this patch set.
I'll add reshape support once all problems are fixed.

Regards
Xiao

On 09/02/2020 08:00 PM, Xiao Ni wrote:
> Hi all
>
> Now mkfs on raid10 which is combined with ssd/nvme disks takes a long time.
> This patch set tries to resolve this problem.
>
> v1:
> Coly helps to review these patches and give some suggestions:
> One bug is found. If discard bio is across one stripe but bio size is
> bigger than one stripe size. After spliting, the bio will be NULL.
> In this version, it checks whether discard bio size is bigger than
> (2*stripe_size).
> In raid10_end_discard_request, it's better to check R10BIO_Uptodate
> is set or not. It can avoid write memory to improve performance.
> Add more comments for calculating addresses.
>
> v2:
> Fix error by checkpatch.pl
> Fix one bug for offset layout. v1 calculates wrongly split size
> Add more comments to explain how the discard range of each component disk
> is decided.
>
> v3:
> add support for far layout
> Change the patch name
>
> v4:
> Pull codes that wait for blocked device into a seprate function
> It can't use (stripe_size-1) as a mask to calculate. (stripe_size-1) may
> not be power of 2.
> It doesn't need to use a full copy of geo.
> Fix warning by checkpatch.pl
>
> v5:
> In 32bit platform, it doesn't support 64bit devide by 32bit value.
> Reported-by: kernel test robot <lkp@intel.com>
>
> v6:
> Move the codes that calculate discard start/size into specific raid type.
> Remove discard support for reshape
>
> Xiao Ni (3):
>    md: calculate discard start address and size in specific raid type
>    md/raid10: improve raid10 discard request
>    md/raid10: improve discard request for far layout
>
>   drivers/md/md.c     |   9 +-
>   drivers/md/md.h     |   3 +-
>   drivers/md/raid0.c  |   5 +-
>   drivers/md/raid10.c | 296 +++++++++++++++++++++++++++++++++++++++++++++++++++-
>   drivers/md/raid10.h |   1 +
>   5 files changed, 303 insertions(+), 11 deletions(-)
>


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request
  2020-09-02 12:00 [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request Xiao Ni
                   ` (3 preceding siblings ...)
  2020-09-02 12:04 ` [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request Xiao Ni
@ 2020-09-15  6:29 ` Song Liu
  4 siblings, 0 replies; 6+ messages in thread
From: Song Liu @ 2020-09-15  6:29 UTC (permalink / raw)
  To: Xiao Ni
  Cc: linux-raid, Heinz Mauelshagen, Nigel Croxon, Guoqing Jiang, Coly Li

On Wed, Sep 2, 2020 at 5:00 AM Xiao Ni <xni@redhat.com> wrote:
>
> Hi all
>
> Now mkfs on raid10 which is combined with ssd/nvme disks takes a long time.
> This patch set tries to resolve this problem.
>
> v1:
> Coly helps to review these patches and give some suggestions:
> One bug is found. If discard bio is across one stripe but bio size is
> bigger than one stripe size. After spliting, the bio will be NULL.
> In this version, it checks whether discard bio size is bigger than
> (2*stripe_size).
> In raid10_end_discard_request, it's better to check R10BIO_Uptodate
> is set or not. It can avoid write memory to improve performance.
> Add more comments for calculating addresses.
>
> v2:
> Fix error by checkpatch.pl
> Fix one bug for offset layout. v1 calculates wrongly split size
> Add more comments to explain how the discard range of each component disk
> is decided.
>
> v3:
> add support for far layout
> Change the patch name
>
> v4:
> Pull codes that wait for blocked device into a seprate function
> It can't use (stripe_size-1) as a mask to calculate. (stripe_size-1) may
> not be power of 2.
> It doesn't need to use a full copy of geo.
> Fix warning by checkpatch.pl
>
> v5:
> In 32bit platform, it doesn't support 64bit devide by 32bit value.
> Reported-by: kernel test robot <lkp@intel.com>
>
> v6:
> Move the codes that calculate discard start/size into specific raid type.
> Remove discard support for reshape

Sorry for the delay.

I apply the set to md-next. Please keep testing and try to fix discard with
reshape. I will also run tests.

Thanks,
Song

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2020-09-15  6:29 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-02 12:00 [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request Xiao Ni
2020-09-02 12:00 ` [PATCH V6 1/3] md: calculate discard start address and size in specific raid type Xiao Ni
2020-09-02 12:00 ` [PATCH V6 2/3] md/raid10: improve raid10 discard request Xiao Ni
2020-09-02 12:00 ` [PATCH V6 3/3] md/raid10: improve discard request for far layout Xiao Ni
2020-09-02 12:04 ` [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request Xiao Ni
2020-09-15  6:29 ` Song Liu

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