// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2016 CNEX Labs * Initial release: Javier Gonzalez <javier@cnexlabs.com> * Matias Bjorling <matias@cnexlabs.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version * 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * pblk-rl.c - pblk's rate limiter for user I/O * */ #include "pblk.h" static void pblk_rl_kick_u_timer(struct pblk_rl *rl) { mod_timer(&rl->u_timer, jiffies + msecs_to_jiffies(5000)); } int pblk_rl_is_limit(struct pblk_rl *rl) { int rb_space; rb_space = atomic_read(&rl->rb_space); return (rb_space == 0); } int pblk_rl_user_may_insert(struct pblk_rl *rl, int nr_entries) { int rb_user_cnt = atomic_read(&rl->rb_user_cnt); int rb_space = atomic_read(&rl->rb_space); if (unlikely(rb_space >= 0) && (rb_space - nr_entries < 0)) return NVM_IO_ERR; if (rb_user_cnt >= rl->rb_user_max) return NVM_IO_REQUEUE; return NVM_IO_OK; } void pblk_rl_inserted(struct pblk_rl *rl, int nr_entries) { int rb_space = atomic_read(&rl->rb_space); if (unlikely(rb_space >= 0)) atomic_sub(nr_entries, &rl->rb_space); } int pblk_rl_gc_may_insert(struct pblk_rl *rl, int nr_entries) { int rb_gc_cnt = atomic_read(&rl->rb_gc_cnt); int rb_user_active; /* If there is no user I/O let GC take over space on the write buffer */ rb_user_active = READ_ONCE(rl->rb_user_active); return (!(rb_gc_cnt >= rl->rb_gc_max && rb_user_active)); } void pblk_rl_user_in(struct pblk_rl *rl, int nr_entries) { atomic_add(nr_entries, &rl->rb_user_cnt); /* Release user I/O state. Protect from GC */ smp_store_release(&rl->rb_user_active, 1); pblk_rl_kick_u_timer(rl); } void pblk_rl_werr_line_in(struct pblk_rl *rl) { atomic_inc(&rl->werr_lines); } void pblk_rl_werr_line_out(struct pblk_rl *rl) { atomic_dec(&rl->werr_lines); } void pblk_rl_gc_in(struct pblk_rl *rl, int nr_entries) { atomic_add(nr_entries, &rl->rb_gc_cnt); } void pblk_rl_out(struct pblk_rl *rl, int nr_user, int nr_gc) { atomic_sub(nr_user, &rl->rb_user_cnt); atomic_sub(nr_gc, &rl->rb_gc_cnt); } unsigned long pblk_rl_nr_free_blks(struct pblk_rl *rl) { return atomic_read(&rl->free_blocks); } 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); int max = rl->rb_budget; int werr_gc_needed = atomic_read(&rl->werr_lines); if (free_blocks >= rl->high) { if (werr_gc_needed) { /* Allocate a small budget for recovering * lines with write errors */ rl->rb_gc_max = 1 << rl->rb_windows_pw; rl->rb_user_max = max - rl->rb_gc_max; rl->rb_state = PBLK_RL_WERR; } else { rl->rb_user_max = max; rl->rb_gc_max = 0; rl->rb_state = PBLK_RL_OFF; } } else if (free_blocks < rl->high) { int shift = rl->high_pw - rl->rb_windows_pw; int user_windows = free_blocks >> shift; int user_max = user_windows << ilog2(NVM_MAX_VLBA); rl->rb_user_max = user_max; rl->rb_gc_max = max - user_max; if (free_blocks <= rl->rsv_blocks) { rl->rb_user_max = 0; rl->rb_gc_max = max; } /* In the worst case, we will need to GC lines in the low list * (high valid sector count). If there are lines to GC on high * or mid lists, these will be prioritized */ rl->rb_state = PBLK_RL_LOW; } if (rl->rb_state != PBLK_RL_OFF) pblk_gc_should_start(pblk); else 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); 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, bool used) { int blk_in_line = atomic_read(&line->blk_in_line); int free_blocks; atomic_sub(blk_in_line, &rl->free_blocks); 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) { return rl->high; } int pblk_rl_max_io(struct pblk_rl *rl) { return rl->rb_max_io; } static void pblk_rl_u_timer(struct timer_list *t) { struct pblk_rl *rl = from_timer(rl, t, u_timer); /* Release user I/O state. Protect from GC */ smp_store_release(&rl->rb_user_active, 0); } void pblk_rl_free(struct pblk_rl *rl) { del_timer(&rl->u_timer); } void pblk_rl_init(struct pblk_rl *rl, int budget, int threshold) { 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 sec_meta, blk_meta; unsigned int rb_windows; /* 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->clba); rl->high = pblk->op_blks - blk_meta - lm->blk_per_line; rl->high_pw = get_count_order(rl->high); rl->rsv_blocks = pblk_get_min_chks(pblk); /* This will always be a power-of-2 */ rb_windows = budget / NVM_MAX_VLBA; rl->rb_windows_pw = get_count_order(rb_windows); /* To start with, all buffer is available to user I/O writers */ rl->rb_budget = budget; rl->rb_user_max = budget; rl->rb_gc_max = 0; rl->rb_state = PBLK_RL_HIGH; /* Maximize I/O size and ansure that back threshold is respected */ if (threshold) rl->rb_max_io = budget - pblk->min_write_pgs_data - threshold; else rl->rb_max_io = budget - pblk->min_write_pgs_data - 1; atomic_set(&rl->rb_user_cnt, 0); atomic_set(&rl->rb_gc_cnt, 0); atomic_set(&rl->rb_space, -1); atomic_set(&rl->werr_lines, 0); timer_setup(&rl->u_timer, pblk_rl_u_timer, 0); rl->rb_user_active = 0; rl->rb_gc_active = 0; }