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From:   Christoph Hellwig <hch@lst.de>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Song Liu <song@kernel.org>, Hans de Goede <hdegoede@redhat.com>,
        Richard Weinberger <richard@nod.at>,
        Minchan Kim <minchan@kernel.org>,
        linux-mtd@lists.infradead.org, dm-devel@redhat.com,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        drbd-dev@lists.linbit.com, linux-raid@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        cgroups@vger.kernel.org
Subject: [PATCH 05/14] md: update the optimal I/O size on reshape
Date:   Fri, 24 Jul 2020 09:33:04 +0200
Message-Id: <20200724073313.138789-6-hch@lst.de>
In-Reply-To: <20200724073313.138789-1-hch@lst.de>
References: <20200724073313.138789-1-hch@lst.de>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The raid5 and raid10 drivers currently update the read-ahead size,
but not the optimal I/O size on reshape.  To prepare for deriving the
read-ahead size from the optimal I/O size make sure it is updated
as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/raid10.c | 22 ++++++++++++++--------
 drivers/md/raid5.c  | 10 ++++++++--
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index b1d0c9d4ef7757..9f88ff9bdee437 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -3695,10 +3695,20 @@ static struct r10conf *setup_conf(struct mddev *mddev)
 	return ERR_PTR(err);
 }
 
+static void raid10_set_io_opt(struct r10conf *conf)
+{
+	int raid_disks = conf->geo.raid_disks;
+
+	if (!(conf->geo.raid_disks % conf->geo.near_copies))
+		raid_disks /= conf->geo.near_copies;
+	blk_queue_io_opt(conf->mddev->queue, (conf->mddev->chunk_sectors << 9) *
+			 raid_disks);
+}
+
 static int raid10_run(struct mddev *mddev)
 {
 	struct r10conf *conf;
-	int i, disk_idx, chunk_size;
+	int i, disk_idx;
 	struct raid10_info *disk;
 	struct md_rdev *rdev;
 	sector_t size;
@@ -3734,18 +3744,13 @@ static int raid10_run(struct mddev *mddev)
 	mddev->thread = conf->thread;
 	conf->thread = NULL;
 
-	chunk_size = mddev->chunk_sectors << 9;
 	if (mddev->queue) {
 		blk_queue_max_discard_sectors(mddev->queue,
 					      mddev->chunk_sectors);
 		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);
-		if (conf->geo.raid_disks % conf->geo.near_copies)
-			blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
-		else
-			blk_queue_io_opt(mddev->queue, chunk_size *
-					 (conf->geo.raid_disks / conf->geo.near_copies));
+		blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
+		raid10_set_io_opt(conf);
 	}
 
 	rdev_for_each(rdev, mddev) {
@@ -4719,6 +4724,7 @@ static void end_reshape(struct r10conf *conf)
 		stripe /= conf->geo.near_copies;
 		if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
 			conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
+		raid10_set_io_opt(conf);
 	}
 	conf->fullsync = 0;
 }
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index d7780b1dd0c528..68e41ce3ca75cc 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7123,6 +7123,12 @@ static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded
 	return 0;
 }
 
+static void raid5_set_io_opt(struct r5conf *conf)
+{
+	blk_queue_io_opt(conf->mddev->queue, (conf->chunk_sectors << 9) *
+			 (conf->raid_disks - conf->max_degraded));
+}
+
 static int raid5_run(struct mddev *mddev)
 {
 	struct r5conf *conf;
@@ -7412,8 +7418,7 @@ static int raid5_run(struct mddev *mddev)
 
 		chunk_size = mddev->chunk_sectors << 9;
 		blk_queue_io_min(mddev->queue, chunk_size);
-		blk_queue_io_opt(mddev->queue, chunk_size *
-				 (conf->raid_disks - conf->max_degraded));
+		raid5_set_io_opt(conf);
 		mddev->queue->limits.raid_partial_stripes_expensive = 1;
 		/*
 		 * We can only discard a whole stripe. It doesn't make sense to
@@ -8006,6 +8011,7 @@ static void end_reshape(struct r5conf *conf)
 						   / PAGE_SIZE);
 			if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
 				conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
+			raid5_set_io_opt(conf);
 		}
 	}
 }
-- 
2.27.0