Re: mirrored device with thousand of mappingtableentries

["Martin K. Petersen" <mkp@mkp.net>]

>>>>> "Mike" == Mike Snitzer <snitzer@redhat.com> writes:

Mike> Thanks for sorting this out.  Can you post a patch that has a
Mike> proper header with your Signed-off-by?  Also including Zdenek's
Mike> Tested-by, and my:

I contemplated a bit and decided I liked the following approach
better. What do you think?


block: Require subsystems to explicitly allocate bio_set integrity mempool

MD and DM create a new bio_set for every metadevice. Each bio_set has an
integrity mempool attached regardless of whether the metadevice is
capable of passing integrity metadata. This is a waste of memory.

Instead we defer the allocation decision to MD and DM since we know at
metadevice creation time whether integrity passthrough is needed or not.

Automatic integrity mempool allocation can then be removed from
bioset_create() and we make an explicit integrity allocation for the
fs_bio_set.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>

---

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 38e4eb1..4e8e314 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -55,6 +55,7 @@ struct dm_table {
 	struct dm_target *targets;
 
 	unsigned discards_supported:1;
+	unsigned integrity_supported:1;
 
 	/*
 	 * Indicates the rw permissions for the new logical
@@ -859,7 +860,7 @@ int dm_table_alloc_md_mempools(struct dm_table *t)
 		return -EINVAL;
 	}
 
-	t->mempools = dm_alloc_md_mempools(type);
+	t->mempools = dm_alloc_md_mempools(type, t->integrity_supported);
 	if (!t->mempools)
 		return -ENOMEM;
 
@@ -935,8 +936,10 @@ static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device
 	struct dm_dev_internal *dd;
 
 	list_for_each_entry(dd, devices, list)
-		if (bdev_get_integrity(dd->dm_dev.bdev))
+		if (bdev_get_integrity(dd->dm_dev.bdev)) {
+			t->integrity_supported = 1;
 			return blk_integrity_register(dm_disk(md), NULL);
+		}
 
 	return 0;
 }
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index eaa3af0..b55ef95 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2643,9 +2643,10 @@ int dm_noflush_suspending(struct dm_target *ti)
 }
 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
 
-struct dm_md_mempools *dm_alloc_md_mempools(unsigned type)
+struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned int integrity)
 {
 	struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
+	unsigned int pool_size = (type == DM_TYPE_BIO_BASED) ? 16 : MIN_IOS;
 
 	if (!pools)
 		return NULL;
@@ -2662,11 +2663,13 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type)
 	if (!pools->tio_pool)
 		goto free_io_pool_and_out;
 
-	pools->bs = (type == DM_TYPE_BIO_BASED) ?
-		    bioset_create(16, 0) : bioset_create(MIN_IOS, 0);
+	pools->bs = bioset_create(pool_size, 0);
 	if (!pools->bs)
 		goto free_tio_pool_and_out;
 
+	if (integrity && bioset_integrity_create(pools->bs, pool_size))
+			goto free_tio_pool_and_out;
+
 	return pools;
 
 free_tio_pool_and_out:
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 0c2dd5f..1aaf167 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -149,7 +149,7 @@ void dm_kcopyd_exit(void);
 /*
  * Mempool operations
  */
-struct dm_md_mempools *dm_alloc_md_mempools(unsigned type);
+struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity);
 void dm_free_md_mempools(struct dm_md_mempools *pools);
 
 #endif
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 818313e..f11e0bc 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1804,8 +1804,12 @@ int md_integrity_register(mddev_t *mddev)
 			mdname(mddev));
 		return -EINVAL;
 	}
-	printk(KERN_NOTICE "md: data integrity on %s enabled\n",
-		mdname(mddev));
+	printk(KERN_NOTICE "md: data integrity enabled on %s\n", mdname(mddev));
+	if (bioset_integrity_create(mddev->bio_set, BIO_POOL_SIZE)) {
+		printk(KERN_ERR "md: failed to create integrity pool for %s\n",
+		       mdname(mddev));
+		return -EINVAL;
+	}
 	return 0;
 }
 EXPORT_SYMBOL(md_integrity_register);
diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index e49cce2..9c5e6b2 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -761,6 +761,9 @@ int bioset_integrity_create(struct bio_set *bs, int pool_size)
 {
 	unsigned int max_slab = vecs_to_idx(BIO_MAX_PAGES);
 
+	if (bs->bio_integrity_pool)
+		return 0;
+
 	bs->bio_integrity_pool =
 		mempool_create_slab_pool(pool_size, bip_slab[max_slab].slab);
 
diff --git a/fs/bio.c b/fs/bio.c
index 4bd454f..06aebf9 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1636,9 +1636,6 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
 	if (!bs->bio_pool)
 		goto bad;
 
-	if (bioset_integrity_create(bs, pool_size))
-		goto bad;
-
 	if (!biovec_create_pools(bs, pool_size))
 		return bs;
 
@@ -1684,6 +1681,9 @@ static int __init init_bio(void)
 	if (!fs_bio_set)
 		panic("bio: can't allocate bios\n");
 
+	if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
+		panic("bio: can't create integrity pool\n");
+
 	bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
 						     sizeof(struct bio_pair));
 	if (!bio_split_pool)