From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: [PATCH 2/1] dm: do not allocate any mempools for blk-mq request-based DM Date: Mon, 27 Apr 2015 21:03:04 -0400 Message-ID: <20150428010303.GB31039@redhat.com> References: <1429957432-20672-1-git-send-email-hch@lst.de> <20150428005950.GA31039@redhat.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20150428005950.GA31039@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Christoph Hellwig Cc: Jens Axboe , dm-devel@redhat.com List-Id: dm-devel.ids 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 --- drivers/md/dm-table.c | 4 +-- drivers/md/dm.c | 69 ++++++++++++++++++++++++++++----------------------- 2 files changed, 40 insertions(+), 33 deletions(-) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 3662b2e..2000fea 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -962,8 +962,8 @@ 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 77ed371..1c0bc67 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2309,39 +2309,52 @@ 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); @@ -2721,14 +2734,6 @@ 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 */ @@ -3450,7 +3455,7 @@ 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); @@ -3469,24 +3474,26 @@ 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) @@ -3495,7 +3502,7 @@ 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) -- 2.3.2 (Apple Git-55)