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