bcache/md: Use raid stripe size
Now that we've got code for raid5/6 stripe awareness, bcache just needs
to know about the stripes and when writing partial stripes is expensive
- we probably don't want to enable this optimization for raid1 or 10,
even though they have stripes. So add a flag to queue_limits.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 05e8267..5d21239 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -592,6 +592,10 @@
ret = -1;
}
+ t->raid_partial_stripes_expensive =
+ max(t->raid_partial_stripes_expensive,
+ b->raid_partial_stripes_expensive);
+
/* Find lowest common alignment_offset */
t->alignment_offset = lcm(t->alignment_offset, alignment)
& (max(t->physical_block_size, t->io_min) - 1);
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 63ebef7..e363efc 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1134,6 +1134,12 @@
hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
}
+ dc->disk.stripe_size = q->limits.io_opt >> 9;
+
+ if (dc->disk.stripe_size)
+ dc->partial_stripes_expensive =
+ q->limits.raid_partial_stripes_expensive;
+
ret = bcache_device_init(&dc->disk, block_size,
dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
if (ret)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index eea6337..1cfb22c 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -6101,6 +6101,7 @@
blk_queue_io_min(mddev->queue, chunk_size);
blk_queue_io_opt(mddev->queue, chunk_size *
(conf->raid_disks - conf->max_degraded));
+ mddev->queue->limits.raid_partial_stripes_expensive = 1;
/*
* We can only discard a whole stripe. It doesn't make sense to
* discard data disk but write parity disk
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 02cb6f0..0375654 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -291,6 +291,7 @@
unsigned char discard_misaligned;
unsigned char cluster;
unsigned char discard_zeroes_data;
+ unsigned char raid_partial_stripes_expensive;
};
struct request_queue {