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dm: do not allocate any mempools for blk-mq request-based DM

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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>
This commit is contained in:
Mike Snitzer 2015-04-27 16:37:50 -04:00
parent 183f7802e7
commit cbc4e3c135
2 changed files with 40 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/md/dm-table.c
View File

@ -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;
}

69
drivers/md/dm.c
View File

@ -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)