From 1e82123da6a4c6019ef03bcd47e4b3dc18dd136e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Javier=20Gonz=C3=A1lez?= Date: Fri, 13 Oct 2017 14:46:25 +0200 Subject: [PATCH] lightnvm: pblk: remove I/O dependency on write path MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit pblk schedules user I/O, metadata I/O and erases on the write path in order to minimize collisions at the media level. Until now, there has been a dependency between user and metadata I/Os that could lead to a deadlock as both take the per-LUN semaphore to schedule submission. This path removes this dependency and guarantees forward progress at a per I/O granurality. Signed-off-by: Javier González Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe --- drivers/lightnvm/pblk-write.c | 145 +++++++++++++++------------------- 1 file changed, 65 insertions(+), 80 deletions(-) diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c index f2e846fe9242..6c1cafafef53 100644 --- a/drivers/lightnvm/pblk-write.c +++ b/drivers/lightnvm/pblk-write.c @@ -220,15 +220,16 @@ static int pblk_alloc_w_rq(struct pblk *pblk, struct nvm_rq *rqd, } static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd, - struct pblk_c_ctx *c_ctx, struct ppa_addr *erase_ppa) + struct ppa_addr *erase_ppa) { struct pblk_line_meta *lm = &pblk->lm; struct pblk_line *e_line = pblk_line_get_erase(pblk); + struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd); unsigned int valid = c_ctx->nr_valid; unsigned int padded = c_ctx->nr_padded; unsigned int nr_secs = valid + padded; unsigned long *lun_bitmap; - int ret = 0; + int ret; lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL); if (!lun_bitmap) @@ -294,55 +295,6 @@ static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail, return secs_to_sync; } -static inline int pblk_valid_meta_ppa(struct pblk *pblk, - struct pblk_line *meta_line, - struct ppa_addr *ppa_list, int nr_ppas) -{ - struct nvm_tgt_dev *dev = pblk->dev; - struct nvm_geo *geo = &dev->geo; - struct pblk_line *data_line; - struct ppa_addr ppa, ppa_opt; - u64 paddr; - int i; - - data_line = &pblk->lines[pblk_dev_ppa_to_line(ppa_list[0])]; - paddr = pblk_lookup_page(pblk, meta_line); - ppa = addr_to_gen_ppa(pblk, paddr, 0); - - if (test_bit(pblk_ppa_to_pos(geo, ppa), data_line->blk_bitmap)) - return 1; - - /* Schedule a metadata I/O that is half the distance from the data I/O - * with regards to the number of LUNs forming the pblk instance. This - * balances LUN conflicts across every I/O. - * - * When the LUN configuration changes (e.g., due to GC), this distance - * can align, which would result on a LUN deadlock. In this case, modify - * the distance to not be optimal, but allow metadata I/Os to succeed. - */ - ppa_opt = addr_to_gen_ppa(pblk, paddr + data_line->meta_distance, 0); - if (unlikely(ppa_opt.ppa == ppa.ppa)) { - data_line->meta_distance--; - return 0; - } - - for (i = 0; i < nr_ppas; i += pblk->min_write_pgs) - if (ppa_list[i].g.ch == ppa_opt.g.ch && - ppa_list[i].g.lun == ppa_opt.g.lun) - return 1; - - if (test_bit(pblk_ppa_to_pos(geo, ppa_opt), data_line->blk_bitmap)) { - for (i = 0; i < nr_ppas; i += pblk->min_write_pgs) - if (ppa_list[i].g.ch == ppa.g.ch && - ppa_list[i].g.lun == ppa.g.lun) - return 0; - - return 1; - } - - return 0; -} - int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line) { struct nvm_tgt_dev *dev = pblk->dev; @@ -421,8 +373,44 @@ fail_free_rqd: return ret; } -static int pblk_sched_meta_io(struct pblk *pblk, struct ppa_addr *prev_list, - int prev_n) +static inline bool pblk_valid_meta_ppa(struct pblk *pblk, + struct pblk_line *meta_line, + struct nvm_rq *data_rqd) +{ + struct nvm_tgt_dev *dev = pblk->dev; + struct nvm_geo *geo = &dev->geo; + struct pblk_c_ctx *data_c_ctx = nvm_rq_to_pdu(data_rqd); + struct pblk_line *data_line = pblk_line_get_data(pblk); + struct ppa_addr ppa, ppa_opt; + u64 paddr; + int pos_opt; + + /* Schedule a metadata I/O that is half the distance from the data I/O + * with regards to the number of LUNs forming the pblk instance. This + * balances LUN conflicts across every I/O. + * + * When the LUN configuration changes (e.g., due to GC), this distance + * can align, which would result on metadata and data I/Os colliding. In + * this case, modify the distance to not be optimal, but move the + * optimal in the right direction. + */ + paddr = pblk_lookup_page(pblk, meta_line); + ppa = addr_to_gen_ppa(pblk, paddr, 0); + ppa_opt = addr_to_gen_ppa(pblk, paddr + data_line->meta_distance, 0); + pos_opt = pblk_ppa_to_pos(geo, ppa_opt); + + if (test_bit(pos_opt, data_c_ctx->lun_bitmap) || + test_bit(pos_opt, data_line->blk_bitmap)) + return true; + + if (unlikely(pblk_ppa_comp(ppa_opt, ppa))) + data_line->meta_distance--; + + return false; +} + +static struct pblk_line *pblk_should_submit_meta_io(struct pblk *pblk, + struct nvm_rq *data_rqd) { struct pblk_line_meta *lm = &pblk->lm; struct pblk_line_mgmt *l_mg = &pblk->l_mg; @@ -432,57 +420,45 @@ static int pblk_sched_meta_io(struct pblk *pblk, struct ppa_addr *prev_list, retry: if (list_empty(&l_mg->emeta_list)) { spin_unlock(&l_mg->close_lock); - return 0; + return NULL; } meta_line = list_first_entry(&l_mg->emeta_list, struct pblk_line, list); if (meta_line->emeta->mem >= lm->emeta_len[0]) goto retry; spin_unlock(&l_mg->close_lock); - if (!pblk_valid_meta_ppa(pblk, meta_line, prev_list, prev_n)) - return 0; + if (!pblk_valid_meta_ppa(pblk, meta_line, data_rqd)) + return NULL; - return pblk_submit_meta_io(pblk, meta_line); + return meta_line; } static int pblk_submit_io_set(struct pblk *pblk, struct nvm_rq *rqd) { - struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd); struct ppa_addr erase_ppa; + struct pblk_line *meta_line; int err; ppa_set_empty(&erase_ppa); /* Assign lbas to ppas and populate request structure */ - err = pblk_setup_w_rq(pblk, rqd, c_ctx, &erase_ppa); + err = pblk_setup_w_rq(pblk, rqd, &erase_ppa); if (err) { pr_err("pblk: could not setup write request: %d\n", err); return NVM_IO_ERR; } - if (likely(ppa_empty(erase_ppa))) { - /* Submit metadata write for previous data line */ - err = pblk_sched_meta_io(pblk, rqd->ppa_list, rqd->nr_ppas); - if (err) { - pr_err("pblk: metadata I/O submission failed: %d", err); - return NVM_IO_ERR; - } + meta_line = pblk_should_submit_meta_io(pblk, rqd); - /* Submit data write for current data line */ - err = pblk_submit_io(pblk, rqd); - if (err) { - pr_err("pblk: data I/O submission failed: %d\n", err); - return NVM_IO_ERR; - } - } else { - /* Submit data write for current data line */ - err = pblk_submit_io(pblk, rqd); - if (err) { - pr_err("pblk: data I/O submission failed: %d\n", err); - return NVM_IO_ERR; - } + /* Submit data write for current data line */ + err = pblk_submit_io(pblk, rqd); + if (err) { + pr_err("pblk: data I/O submission failed: %d\n", err); + return NVM_IO_ERR; + } - /* Submit available erase for next data line */ + if (!ppa_empty(erase_ppa)) { + /* Submit erase for next data line */ if (pblk_blk_erase_async(pblk, erase_ppa)) { struct pblk_line *e_line = pblk_line_get_erase(pblk); struct nvm_tgt_dev *dev = pblk->dev; @@ -495,6 +471,15 @@ static int pblk_submit_io_set(struct pblk *pblk, struct nvm_rq *rqd) } } + if (meta_line) { + /* Submit metadata write for previous data line */ + err = pblk_submit_meta_io(pblk, meta_line); + if (err) { + pr_err("pblk: metadata I/O submission failed: %d", err); + return NVM_IO_ERR; + } + } + return NVM_IO_OK; }