From a7689938ef4c8678ff78c44d11e4b0b897244714 Mon Sep 17 00:00:00 2001 From: Javier González Date: Fri, 5 Jan 2018 14:16:13 +0100 Subject: lightnvm: pblk: use exact free block counter in RL Until now, pblk's rate-limiter has used a heuristic to reserve space for GC I/O given that the over-provision area was fixed. In preparation for allowing to define the over-provision area on target creation, define a dedicated free_block counter in the rate-limiter to track the number of blocks being used for user data. Signed-off-by: Javier González Signed-off-by: Hans Holmberg Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe --- drivers/lightnvm/pblk-rl.c | 54 +++++++++++++++++++++++++++++++--------------- 1 file changed, 37 insertions(+), 17 deletions(-) (limited to 'drivers/lightnvm/pblk-rl.c') diff --git a/drivers/lightnvm/pblk-rl.c b/drivers/lightnvm/pblk-rl.c index dacc71922260..0d457b162f23 100644 --- a/drivers/lightnvm/pblk-rl.c +++ b/drivers/lightnvm/pblk-rl.c @@ -89,17 +89,15 @@ unsigned long pblk_rl_nr_free_blks(struct pblk_rl *rl) return atomic_read(&rl->free_blocks); } -/* - * We check for (i) the number of free blocks in the current LUN and (ii) the - * total number of free blocks in the pblk instance. This is to even out the - * number of free blocks on each LUN when GC kicks in. - * - * Only the total number of free blocks is used to configure the rate limiter. - */ -void pblk_rl_update_rates(struct pblk_rl *rl) +unsigned long pblk_rl_nr_user_free_blks(struct pblk_rl *rl) +{ + return atomic_read(&rl->free_user_blocks); +} + +static void __pblk_rl_update_rates(struct pblk_rl *rl, + unsigned long free_blocks) { struct pblk *pblk = container_of(rl, struct pblk, rl); - unsigned long free_blocks = pblk_rl_nr_free_blks(rl); int max = rl->rb_budget; if (free_blocks >= rl->high) { @@ -132,20 +130,37 @@ void pblk_rl_update_rates(struct pblk_rl *rl) pblk_gc_should_stop(pblk); } +void pblk_rl_update_rates(struct pblk_rl *rl) +{ + __pblk_rl_update_rates(rl, pblk_rl_nr_user_free_blks(rl)); +} + void pblk_rl_free_lines_inc(struct pblk_rl *rl, struct pblk_line *line) { int blk_in_line = atomic_read(&line->blk_in_line); + int free_blocks; atomic_add(blk_in_line, &rl->free_blocks); - pblk_rl_update_rates(rl); + free_blocks = atomic_add_return(blk_in_line, &rl->free_user_blocks); + + __pblk_rl_update_rates(rl, free_blocks); } -void pblk_rl_free_lines_dec(struct pblk_rl *rl, struct pblk_line *line) +void pblk_rl_free_lines_dec(struct pblk_rl *rl, struct pblk_line *line, + bool used) { int blk_in_line = atomic_read(&line->blk_in_line); + int free_blocks; atomic_sub(blk_in_line, &rl->free_blocks); - pblk_rl_update_rates(rl); + + if (used) + free_blocks = atomic_sub_return(blk_in_line, + &rl->free_user_blocks); + else + free_blocks = atomic_read(&rl->free_user_blocks); + + __pblk_rl_update_rates(rl, free_blocks); } int pblk_rl_high_thrs(struct pblk_rl *rl) @@ -174,16 +189,21 @@ void pblk_rl_free(struct pblk_rl *rl) void pblk_rl_init(struct pblk_rl *rl, int budget) { struct pblk *pblk = container_of(rl, struct pblk, rl); + struct nvm_tgt_dev *dev = pblk->dev; + struct nvm_geo *geo = &dev->geo; + struct pblk_line_mgmt *l_mg = &pblk->l_mg; struct pblk_line_meta *lm = &pblk->lm; int min_blocks = lm->blk_per_line * PBLK_GC_RSV_LINE; + int sec_meta, blk_meta; + unsigned int rb_windows; - rl->high = rl->total_blocks / PBLK_USER_HIGH_THRS; - rl->high_pw = get_count_order(rl->high); + /* Consider sectors used for metadata */ + sec_meta = (lm->smeta_sec + lm->emeta_sec[0]) * l_mg->nr_free_lines; + blk_meta = DIV_ROUND_UP(sec_meta, geo->sec_per_chk); - rl->low = rl->total_blocks / PBLK_USER_LOW_THRS; - if (rl->low < min_blocks) - rl->low = min_blocks; + rl->high = pblk->op_blks - blk_meta - lm->blk_per_line; + rl->high_pw = get_count_order(rl->high); rl->rsv_blocks = min_blocks; -- cgit v1.2.3-55-g7522