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authorMike Snitzer <snitzer@redhat.com>2015-04-27 16:37:50 -0400
committerMike Snitzer <snitzer@redhat.com>2015-05-29 14:18:57 -0400
commitcbc4e3c1350beb47beab8f34ad9be3d34a20c705 (patch)
tree443ef957c07dd59b979057be737f733e5142b2d3
parent183f7802e73e26206558864d1b67e64382257277 (diff)
downloadlinux-cbc4e3c1350beb47beab8f34ad9be3d34a20c705.tar.bz2
dm: do not allocate any mempools for blk-mq request-based DM
Do not allocate the io_pool mempool for blk-mq request-based DM (DM_TYPE_MQ_REQUEST_BASED) in dm_alloc_rq_mempools(). Also refine __bind_mempools() to have more precise awareness of which mempools each type of DM device uses -- avoids mempool churn when reloading DM tables (particularly for DM_TYPE_REQUEST_BASED). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-rw-r--r--drivers/md/dm-table.c4
-rw-r--r--drivers/md/dm.c69
2 files changed, 40 insertions, 33 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index a5f94125ad01..85e1d39e9a38 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -964,8 +964,8 @@ static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *
return -EINVAL;
}
- if (!t->mempools)
- return -ENOMEM;
+ if (IS_ERR(t->mempools))
+ return PTR_ERR(t->mempools);
return 0;
}
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 4d6f089a0e9e..916f6015981c 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2323,39 +2323,52 @@ static void free_dev(struct mapped_device *md)
kfree(md);
}
+static unsigned filter_md_type(unsigned type, struct mapped_device *md)
+{
+ if (type == DM_TYPE_BIO_BASED)
+ return type;
+
+ return !md->use_blk_mq ? DM_TYPE_REQUEST_BASED : DM_TYPE_MQ_REQUEST_BASED;
+}
+
static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
{
struct dm_md_mempools *p = dm_table_get_md_mempools(t);
- if (md->bs) {
- /* The md already has necessary mempools. */
- if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) {
+ switch (filter_md_type(dm_table_get_type(t), md)) {
+ case DM_TYPE_BIO_BASED:
+ if (md->bs && md->io_pool) {
/*
+ * This bio-based md already has necessary mempools.
* Reload bioset because front_pad may have changed
* because a different table was loaded.
*/
bioset_free(md->bs);
md->bs = p->bs;
p->bs = NULL;
+ goto out;
}
- /*
- * There's no need to reload with request-based dm
- * because the size of front_pad doesn't change.
- * Note for future: If you are to reload bioset,
- * prep-ed requests in the queue may refer
- * to bio from the old bioset, so you must walk
- * through the queue to unprep.
- */
- goto out;
+ break;
+ case DM_TYPE_REQUEST_BASED:
+ if (md->rq_pool && md->io_pool)
+ /*
+ * This request-based md already has necessary mempools.
+ */
+ goto out;
+ break;
+ case DM_TYPE_MQ_REQUEST_BASED:
+ BUG_ON(p); /* No mempools needed */
+ return;
}
+ BUG_ON(!p || md->io_pool || md->rq_pool || md->bs);
+
md->io_pool = p->io_pool;
p->io_pool = NULL;
md->rq_pool = p->rq_pool;
p->rq_pool = NULL;
md->bs = p->bs;
p->bs = NULL;
-
out:
/* mempool bind completed, no longer need any mempools in the table */
dm_table_free_md_mempools(t);
@@ -2734,14 +2747,6 @@ out_tag_set:
return err;
}
-static unsigned filter_md_type(unsigned type, struct mapped_device *md)
-{
- if (type == DM_TYPE_BIO_BASED)
- return type;
-
- return !md->use_blk_mq ? DM_TYPE_REQUEST_BASED : DM_TYPE_MQ_REQUEST_BASED;
-}
-
/*
* Setup the DM device's queue based on md's type
*/
@@ -3463,7 +3468,7 @@ struct dm_md_mempools *dm_alloc_bio_mempools(unsigned integrity,
pools = kzalloc(sizeof(*pools), GFP_KERNEL);
if (!pools)
- return NULL;
+ return ERR_PTR(-ENOMEM);
front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) +
offsetof(struct dm_target_io, clone);
@@ -3482,24 +3487,26 @@ struct dm_md_mempools *dm_alloc_bio_mempools(unsigned integrity,
return pools;
out:
dm_free_md_mempools(pools);
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
struct dm_md_mempools *dm_alloc_rq_mempools(struct mapped_device *md,
unsigned type)
{
- unsigned int pool_size = dm_get_reserved_rq_based_ios();
+ unsigned int pool_size;
struct dm_md_mempools *pools;
+ if (filter_md_type(type, md) == DM_TYPE_MQ_REQUEST_BASED)
+ return NULL; /* No mempools needed */
+
+ pool_size = dm_get_reserved_rq_based_ios();
pools = kzalloc(sizeof(*pools), GFP_KERNEL);
if (!pools)
- return NULL;
+ return ERR_PTR(-ENOMEM);
- if (filter_md_type(type, md) == DM_TYPE_REQUEST_BASED) {
- pools->rq_pool = mempool_create_slab_pool(pool_size, _rq_cache);
- if (!pools->rq_pool)
- goto out;
- }
+ pools->rq_pool = mempool_create_slab_pool(pool_size, _rq_cache);
+ if (!pools->rq_pool)
+ goto out;
pools->io_pool = mempool_create_slab_pool(pool_size, _rq_tio_cache);
if (!pools->io_pool)
@@ -3508,7 +3515,7 @@ struct dm_md_mempools *dm_alloc_rq_mempools(struct mapped_device *md,
return pools;
out:
dm_free_md_mempools(pools);
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
void dm_free_md_mempools(struct dm_md_mempools *pools)