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![Kees Cook](/assets/img/avatar_default.png)
In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: Matias Bjorling <mb@lightnvm.io> Cc: linux-block@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
209 lines
5.2 KiB
C
209 lines
5.2 KiB
C
/*
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* Copyright (C) 2016 CNEX Labs
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* Initial release: Javier Gonzalez <javier@cnexlabs.com>
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* Matias Bjorling <matias@cnexlabs.com>
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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_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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/*
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* We check for (i) the number of free blocks in the current LUN and (ii) the
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* total number of free blocks in the pblk instance. This is to even out the
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* number of free blocks on each LUN when GC kicks in.
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*
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* Only the total number of free blocks is used to configure the rate limiter.
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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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struct pblk *pblk = container_of(rl, struct pblk, rl);
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unsigned long free_blocks = pblk_rl_nr_free_blks(rl);
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int max = rl->rb_budget;
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if (free_blocks >= rl->high) {
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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_HIGH;
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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 << PBLK_MAX_REQ_ADDRS_PW;
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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_MID | PBLK_RL_LOW))
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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_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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atomic_add(blk_in_line, &rl->free_blocks);
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pblk_rl_update_rates(rl);
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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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{
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int blk_in_line = atomic_read(&line->blk_in_line);
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atomic_sub(blk_in_line, &rl->free_blocks);
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pblk_rl_update_rates(rl);
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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)
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{
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struct pblk *pblk = container_of(rl, struct pblk, rl);
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struct pblk_line_meta *lm = &pblk->lm;
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int min_blocks = lm->blk_per_line * PBLK_GC_RSV_LINE;
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unsigned int rb_windows;
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rl->high = rl->total_blocks / PBLK_USER_HIGH_THRS;
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rl->high_pw = get_count_order(rl->high);
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rl->low = rl->total_blocks / PBLK_USER_LOW_THRS;
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if (rl->low < min_blocks)
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rl->low = min_blocks;
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rl->rsv_blocks = min_blocks;
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/* This will always be a power-of-2 */
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rb_windows = budget / PBLK_MAX_REQ_ADDRS;
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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_max_io = budget >> 1;
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rl->rb_gc_max = 0;
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rl->rb_state = PBLK_RL_HIGH;
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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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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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