Commit c78afc62 authored by Kent Overstreet's avatar Kent Overstreet

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: default avatarKent Overstreet <kmo@daterainc.com>
parent 5f5837d2
......@@ -592,6 +592,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
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);
......
......@@ -1134,6 +1134,12 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
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)
......
......@@ -6101,6 +6101,7 @@ static int run(struct mddev *mddev)
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
......
......@@ -291,6 +291,7 @@ struct queue_limits {
unsigned char discard_misaligned;
unsigned char cluster;
unsigned char discard_zeroes_data;
unsigned char raid_partial_stripes_expensive;
};
struct request_queue {
......
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