Allows the null_blk driver to hook into LightNVM for performance evaluation.
It is activated by passing lightnvm_enable parameter at module load. The number of channels exposed to LightNVM can be configured through the lightnvm_num_channels module parameter. Contributions in this patch from: Jesper Madsen <[email protected]> Signed-off-by: Matias Bjørling <[email protected]> --- Documentation/block/null_blk.txt | 8 ++++ drivers/block/null_blk.c | 89 +++++++++++++++++++++++++++++++++++++--- 2 files changed, 92 insertions(+), 5 deletions(-) diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt index b2830b4..a35e928 100644 --- a/Documentation/block/null_blk.txt +++ b/Documentation/block/null_blk.txt @@ -70,3 +70,11 @@ use_per_node_hctx=[0/1]: Default: 0 parameter. 1: The multi-queue block layer is instantiated with a hardware dispatch queue for each CPU node in the system. + +IV: LightNVM specific parameters + +lightnvm_enable=[x]: Default: 0 + Enable LightNVM for null block devices. Requires blk-mq to be used. + +lightnvm_num_channels=[x]: Default: 1 + Number of LightNVM channels that are exposed to the LightNVM driver. diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index 00d469c..4462941 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -7,6 +7,7 @@ #include <linux/init.h> #include <linux/slab.h> #include <linux/blk-mq.h> +#include <linux/lightnvm.h> #include <linux/hrtimer.h> struct nullb_cmd { @@ -109,6 +110,14 @@ static bool use_per_node_hctx = false; module_param(use_per_node_hctx, bool, S_IRUGO); MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false"); +static bool lightnvm_enable = false; +module_param(lightnvm_enable, bool, S_IRUGO); +MODULE_PARM_DESC(lightnvm_enable, "Enable LightNVM. Default: false"); + +static int lightnvm_num_channels = 1; +module_param(lightnvm_num_channels, int, S_IRUGO); +MODULE_PARM_DESC(lightnvm_num_channels, "Number of channels to be exposed to LightNVM. Default: 1"); + static void put_tag(struct nullb_queue *nq, unsigned int tag) { clear_bit_unlock(tag, nq->tag_map); @@ -313,6 +322,55 @@ static void null_request_fn(struct request_queue *q) } } +static int null_nvm_id(struct request_queue *q, struct nvm_id *id) +{ + sector_t size = gb * 1024 * 1024 * 1024ULL; + unsigned long per_chnl_size = + size / bs / lightnvm_num_channels; + struct nvm_id_chnl *chnl; + int i; + + id->ver_id = 0x1; + id->nvm_type = NVM_NVMT_BLK; + id->nchannels = lightnvm_num_channels; + + id->chnls = kmalloc(sizeof(struct nvm_id_chnl) * id->nchannels, + GFP_KERNEL); + if (!id->chnls) + return -ENOMEM; + + for (i = 0; i < id->nchannels; i++) { + chnl = &id->chnls[i]; + chnl->queue_size = hw_queue_depth; + chnl->gran_read = bs; + chnl->gran_write = bs; + chnl->gran_erase = bs * 256; + chnl->oob_size = 0; + chnl->t_r = chnl->t_sqr = 25000; /* 25us */ + chnl->t_w = chnl->t_sqw = 500000; /* 500us */ + chnl->t_e = 1500000; /* 1.500us */ + chnl->io_sched = NVM_IOSCHED_CHANNEL; + chnl->laddr_begin = per_chnl_size * i; + chnl->laddr_end = per_chnl_size * (i + 1) - 1; + } + + return 0; +} + +static int null_nvm_get_features(struct request_queue *q, + struct nvm_get_features *gf) +{ + gf->rsp[0] = (1 << NVM_RSP_L2P); + gf->rsp[0] |= (1 << NVM_RSP_P2L); + gf->rsp[0] |= (1 << NVM_RSP_GC); + return 0; +} + +static int null_nvm_set_rsp(struct request_queue *q, u8 rsp, u8 val) +{ + return NVM_RID_NOT_CHANGEABLE | NVM_DNR; +} + static int null_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq) { struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); @@ -346,6 +404,12 @@ static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, return 0; } +static struct lightnvm_dev_ops null_nvm_dev_ops = { + .identify = null_nvm_id, + .get_features = null_nvm_get_features, + .set_responsibility = null_nvm_set_rsp, +}; + static struct blk_mq_ops null_mq_ops = { .queue_rq = null_queue_rq, .map_queue = blk_mq_map_queue, @@ -488,6 +552,11 @@ static int null_add_dev(void) nullb->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; nullb->tag_set.driver_data = nullb; + if (lightnvm_enable) { + nullb->tag_set.flags &= ~BLK_MQ_F_SHOULD_MERGE; + nullb->tag_set.flags |= BLK_MQ_F_LIGHTNVM; + } + rv = blk_mq_alloc_tag_set(&nullb->tag_set); if (rv) goto out_cleanup_queues; @@ -525,11 +594,6 @@ static int null_add_dev(void) goto out_cleanup_blk_queue; } - mutex_lock(&lock); - list_add_tail(&nullb->list, &nullb_list); - nullb->index = nullb_indexes++; - mutex_unlock(&lock); - blk_queue_logical_block_size(nullb->q, bs); blk_queue_physical_block_size(nullb->q, bs); @@ -543,10 +607,25 @@ static int null_add_dev(void) disk->fops = &null_fops; disk->private_data = nullb; disk->queue = nullb->q; + + if (lightnvm_enable && queue_mode == NULL_Q_MQ) { + if (blk_lightnvm_register(nullb->q, &null_nvm_dev_ops)) + goto out_cleanup_nvm; + + nullb->q->nvm->drv_cmd_size = sizeof(struct nullb_cmd); + } + + mutex_lock(&lock); + list_add_tail(&nullb->list, &nullb_list); + nullb->index = nullb_indexes++; + mutex_unlock(&lock); + sprintf(disk->disk_name, "nullb%d", nullb->index); add_disk(disk); return 0; +out_cleanup_nvm: + put_disk(disk); out_cleanup_blk_queue: blk_cleanup_queue(nullb->q); out_cleanup_tags: -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
