Re: [PATCH 10/13] lightnvm: pblk: Reduce L2P DRAM footprint

["Matias Bjørling" <mb@lightnvm.io>]

On 2/27/19 6:14 PM, Igor Konopko wrote:
> Currently L2P map size is calculated based on
> the total number of available sectors, which is
> redundant, since it contains some number of
> over provisioning (11% by default).
> 
> The goal of this patch is to change this size
> to the real capacity and thus reduce the DRAM
> footprint significantly - with default op value
> it is approx. 110MB of DRAM less for every 1TB
> of pblk drive.
> 
> Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
> ---
>   drivers/lightnvm/pblk-core.c     | 8 ++++----
>   drivers/lightnvm/pblk-init.c     | 7 +++----
>   drivers/lightnvm/pblk-read.c     | 2 +-
>   drivers/lightnvm/pblk-recovery.c | 2 +-
>   drivers/lightnvm/pblk.h          | 1 -
>   5 files changed, 9 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> index f48f2e77f770..2e424c0275c1 100644
> --- a/drivers/lightnvm/pblk-core.c
> +++ b/drivers/lightnvm/pblk-core.c
> @@ -2024,7 +2024,7 @@ void pblk_update_map(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
>   	struct ppa_addr ppa_l2p;
>   
>   	/* logic error: lba out-of-bounds. Ignore update */
> -	if (!(lba < pblk->rl.nr_secs)) {
> +	if (!(lba < pblk->capacity)) {
>   		WARN(1, "pblk: corrupted L2P map request\n");
>   		return;
>   	}
> @@ -2064,7 +2064,7 @@ int pblk_update_map_gc(struct pblk *pblk, sector_t lba, struct ppa_addr ppa_new,
>   #endif
>   
>   	/* logic error: lba out-of-bounds. Ignore update */
> -	if (!(lba < pblk->rl.nr_secs)) {
> +	if (!(lba < pblk->capacity)) {
>   		WARN(1, "pblk: corrupted L2P map request\n");
>   		return 0;
>   	}
> @@ -2110,7 +2110,7 @@ void pblk_update_map_dev(struct pblk *pblk, sector_t lba,
>   	}
>   
>   	/* logic error: lba out-of-bounds. Ignore update */
> -	if (!(lba < pblk->rl.nr_secs)) {
> +	if (!(lba < pblk->capacity)) {
>   		WARN(1, "pblk: corrupted L2P map request\n");
>   		return;
>   	}
> @@ -2168,7 +2168,7 @@ void pblk_lookup_l2p_rand(struct pblk *pblk, struct ppa_addr *ppas,
>   		lba = lba_list[i];
>   		if (lba != ADDR_EMPTY) {
>   			/* logic error: lba out-of-bounds. Ignore update */
> -			if (!(lba < pblk->rl.nr_secs)) {
> +			if (!(lba < pblk->capacity)) {
>   				WARN(1, "pblk: corrupted L2P map request\n");
>   				continue;
>   			}
> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> index e553105b7ba1..9913a4514eb6 100644
> --- a/drivers/lightnvm/pblk-init.c
> +++ b/drivers/lightnvm/pblk-init.c
> @@ -105,7 +105,7 @@ static size_t pblk_trans_map_size(struct pblk *pblk)
>   	if (pblk->addrf_len < 32)
>   		entry_size = 4;
>   
> -	return entry_size * pblk->rl.nr_secs;
> +	return entry_size * pblk->capacity;
>   }
>   
>   #ifdef CONFIG_NVM_PBLK_DEBUG
> @@ -175,7 +175,7 @@ static int pblk_l2p_init(struct pblk *pblk, bool factory_init)
>   
>   	pblk_ppa_set_empty(&ppa);
>   
> -	for (i = 0; i < pblk->rl.nr_secs; i++)
> +	for (i = 0; i < pblk->capacity; i++)
>   		pblk_trans_map_set(pblk, i, ppa);
>   
>   	ret = pblk_l2p_recover(pblk, factory_init);
> @@ -706,7 +706,6 @@ static int pblk_set_provision(struct pblk *pblk, int nr_free_chks)
>   	 * on user capacity consider only provisioned blocks
>   	 */
>   	pblk->rl.total_blocks = nr_free_chks;
> -	pblk->rl.nr_secs = nr_free_chks * geo->clba;
>   
>   	/* Consider sectors used for metadata */
>   	sec_meta = (lm->smeta_sec + lm->emeta_sec[0]) * l_mg->nr_free_lines;
> @@ -1289,7 +1288,7 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
>   
>   	pblk_info(pblk, "luns:%u, lines:%d, secs:%llu, buf entries:%u\n",
>   			geo->all_luns, pblk->l_mg.nr_lines,
> -			(unsigned long long)pblk->rl.nr_secs,
> +			(unsigned long long)pblk->capacity,
>   			pblk->rwb.nr_entries);
>   
>   	wake_up_process(pblk->writer_ts);
> diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
> index 39c1d6ccaedb..65697463def8 100644
> --- a/drivers/lightnvm/pblk-read.c
> +++ b/drivers/lightnvm/pblk-read.c
> @@ -561,7 +561,7 @@ static int read_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
>   		goto out;
>   
>   	/* logic error: lba out-of-bounds */
> -	if (lba >= pblk->rl.nr_secs) {
> +	if (lba >= pblk->capacity) {
>   		WARN(1, "pblk: read lba out of bounds\n");
>   		goto out;
>   	}
> diff --git a/drivers/lightnvm/pblk-recovery.c b/drivers/lightnvm/pblk-recovery.c
> index d86f580036d3..83b467b5edc7 100644
> --- a/drivers/lightnvm/pblk-recovery.c
> +++ b/drivers/lightnvm/pblk-recovery.c
> @@ -474,7 +474,7 @@ static int pblk_recov_scan_oob(struct pblk *pblk, struct pblk_line *line,
>   
>   		lba_list[paddr++] = cpu_to_le64(lba);
>   
> -		if (lba == ADDR_EMPTY || lba > pblk->rl.nr_secs)
> +		if (lba == ADDR_EMPTY || lba >= pblk->capacity)
>   			continue;
>   
>   		line->nr_valid_lbas++;
> diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
> index a6386d5acd73..a92377530930 100644
> --- a/drivers/lightnvm/pblk.h
> +++ b/drivers/lightnvm/pblk.h
> @@ -305,7 +305,6 @@ struct pblk_rl {
>   
>   	struct timer_list u_timer;
>   
> -	unsigned long long nr_secs;
>   	unsigned long total_blocks;
>   
>   	atomic_t free_blocks;		/* Total number of free blocks (+ OP) */
> 

Thanks Igor. Applied for 5.2. I've also updated the text a bit.