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02a1520d | 1 | // SPDX-License-Identifier: GPL-2.0 |
a4bd217b JG |
2 | /* |
3 | * Copyright (C) 2016 CNEX Labs | |
4 | * Initial release: Javier Gonzalez <javier@cnexlabs.com> | |
5 | * Matias Bjorling <matias@cnexlabs.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License version | |
9 | * 2 as published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, but | |
12 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * pblk-rl.c - pblk's rate limiter for user I/O | |
17 | * | |
18 | */ | |
19 | ||
20 | #include "pblk.h" | |
21 | ||
22 | static void pblk_rl_kick_u_timer(struct pblk_rl *rl) | |
23 | { | |
24 | mod_timer(&rl->u_timer, jiffies + msecs_to_jiffies(5000)); | |
25 | } | |
26 | ||
588726d3 JG |
27 | int pblk_rl_is_limit(struct pblk_rl *rl) |
28 | { | |
29 | int rb_space; | |
30 | ||
31 | rb_space = atomic_read(&rl->rb_space); | |
32 | ||
33 | return (rb_space == 0); | |
34 | } | |
35 | ||
a4bd217b JG |
36 | int pblk_rl_user_may_insert(struct pblk_rl *rl, int nr_entries) |
37 | { | |
38 | int rb_user_cnt = atomic_read(&rl->rb_user_cnt); | |
588726d3 JG |
39 | int rb_space = atomic_read(&rl->rb_space); |
40 | ||
41 | if (unlikely(rb_space >= 0) && (rb_space - nr_entries < 0)) | |
42 | return NVM_IO_ERR; | |
43 | ||
44 | if (rb_user_cnt >= rl->rb_user_max) | |
45 | return NVM_IO_REQUEUE; | |
a4bd217b | 46 | |
588726d3 JG |
47 | return NVM_IO_OK; |
48 | } | |
49 | ||
50 | void pblk_rl_inserted(struct pblk_rl *rl, int nr_entries) | |
51 | { | |
52 | int rb_space = atomic_read(&rl->rb_space); | |
53 | ||
54 | if (unlikely(rb_space >= 0)) | |
55 | atomic_sub(nr_entries, &rl->rb_space); | |
a4bd217b JG |
56 | } |
57 | ||
58 | int pblk_rl_gc_may_insert(struct pblk_rl *rl, int nr_entries) | |
59 | { | |
60 | int rb_gc_cnt = atomic_read(&rl->rb_gc_cnt); | |
61 | int rb_user_active; | |
62 | ||
63 | /* If there is no user I/O let GC take over space on the write buffer */ | |
64 | rb_user_active = READ_ONCE(rl->rb_user_active); | |
b20ba1bc | 65 | return (!(rb_gc_cnt >= rl->rb_gc_max && rb_user_active)); |
a4bd217b JG |
66 | } |
67 | ||
68 | void pblk_rl_user_in(struct pblk_rl *rl, int nr_entries) | |
69 | { | |
70 | atomic_add(nr_entries, &rl->rb_user_cnt); | |
71 | ||
72 | /* Release user I/O state. Protect from GC */ | |
73 | smp_store_release(&rl->rb_user_active, 1); | |
74 | pblk_rl_kick_u_timer(rl); | |
75 | } | |
76 | ||
48b8d208 HH |
77 | void pblk_rl_werr_line_in(struct pblk_rl *rl) |
78 | { | |
79 | atomic_inc(&rl->werr_lines); | |
80 | } | |
81 | ||
82 | void pblk_rl_werr_line_out(struct pblk_rl *rl) | |
83 | { | |
84 | atomic_dec(&rl->werr_lines); | |
85 | } | |
86 | ||
a4bd217b JG |
87 | void pblk_rl_gc_in(struct pblk_rl *rl, int nr_entries) |
88 | { | |
89 | atomic_add(nr_entries, &rl->rb_gc_cnt); | |
90 | } | |
91 | ||
92 | void pblk_rl_out(struct pblk_rl *rl, int nr_user, int nr_gc) | |
93 | { | |
94 | atomic_sub(nr_user, &rl->rb_user_cnt); | |
95 | atomic_sub(nr_gc, &rl->rb_gc_cnt); | |
96 | } | |
97 | ||
98 | unsigned long pblk_rl_nr_free_blks(struct pblk_rl *rl) | |
99 | { | |
100 | return atomic_read(&rl->free_blocks); | |
101 | } | |
102 | ||
a7689938 JG |
103 | unsigned long pblk_rl_nr_user_free_blks(struct pblk_rl *rl) |
104 | { | |
105 | return atomic_read(&rl->free_user_blocks); | |
106 | } | |
107 | ||
108 | static void __pblk_rl_update_rates(struct pblk_rl *rl, | |
109 | unsigned long free_blocks) | |
a4bd217b | 110 | { |
32825ebb | 111 | struct pblk *pblk = container_of(rl, struct pblk, rl); |
32825ebb | 112 | int max = rl->rb_budget; |
48b8d208 | 113 | int werr_gc_needed = atomic_read(&rl->werr_lines); |
a4bd217b JG |
114 | |
115 | if (free_blocks >= rl->high) { | |
48b8d208 HH |
116 | if (werr_gc_needed) { |
117 | /* Allocate a small budget for recovering | |
118 | * lines with write errors | |
119 | */ | |
120 | rl->rb_gc_max = 1 << rl->rb_windows_pw; | |
121 | rl->rb_user_max = max - rl->rb_gc_max; | |
122 | rl->rb_state = PBLK_RL_WERR; | |
123 | } else { | |
124 | rl->rb_user_max = max; | |
125 | rl->rb_gc_max = 0; | |
126 | rl->rb_state = PBLK_RL_OFF; | |
127 | } | |
a4bd217b JG |
128 | } else if (free_blocks < rl->high) { |
129 | int shift = rl->high_pw - rl->rb_windows_pw; | |
130 | int user_windows = free_blocks >> shift; | |
afdc23c9 | 131 | int user_max = user_windows << ilog2(NVM_MAX_VLBA); |
a4bd217b JG |
132 | |
133 | rl->rb_user_max = user_max; | |
b20ba1bc JG |
134 | rl->rb_gc_max = max - user_max; |
135 | ||
136 | if (free_blocks <= rl->rsv_blocks) { | |
137 | rl->rb_user_max = 0; | |
138 | rl->rb_gc_max = max; | |
139 | } | |
140 | ||
141 | /* In the worst case, we will need to GC lines in the low list | |
142 | * (high valid sector count). If there are lines to GC on high | |
143 | * or mid lists, these will be prioritized | |
144 | */ | |
145 | rl->rb_state = PBLK_RL_LOW; | |
a4bd217b JG |
146 | } |
147 | ||
48b8d208 | 148 | if (rl->rb_state != PBLK_RL_OFF) |
32825ebb RP |
149 | pblk_gc_should_start(pblk); |
150 | else | |
151 | pblk_gc_should_stop(pblk); | |
a4bd217b JG |
152 | } |
153 | ||
a7689938 JG |
154 | void pblk_rl_update_rates(struct pblk_rl *rl) |
155 | { | |
156 | __pblk_rl_update_rates(rl, pblk_rl_nr_user_free_blks(rl)); | |
157 | } | |
158 | ||
a4bd217b JG |
159 | void pblk_rl_free_lines_inc(struct pblk_rl *rl, struct pblk_line *line) |
160 | { | |
a44f53fa | 161 | int blk_in_line = atomic_read(&line->blk_in_line); |
a7689938 | 162 | int free_blocks; |
a4bd217b | 163 | |
a44f53fa | 164 | atomic_add(blk_in_line, &rl->free_blocks); |
a7689938 JG |
165 | free_blocks = atomic_add_return(blk_in_line, &rl->free_user_blocks); |
166 | ||
167 | __pblk_rl_update_rates(rl, free_blocks); | |
a4bd217b JG |
168 | } |
169 | ||
a7689938 JG |
170 | void pblk_rl_free_lines_dec(struct pblk_rl *rl, struct pblk_line *line, |
171 | bool used) | |
a4bd217b | 172 | { |
a44f53fa | 173 | int blk_in_line = atomic_read(&line->blk_in_line); |
a7689938 | 174 | int free_blocks; |
a4bd217b | 175 | |
a44f53fa | 176 | atomic_sub(blk_in_line, &rl->free_blocks); |
a7689938 JG |
177 | |
178 | if (used) | |
179 | free_blocks = atomic_sub_return(blk_in_line, | |
180 | &rl->free_user_blocks); | |
181 | else | |
182 | free_blocks = atomic_read(&rl->free_user_blocks); | |
183 | ||
184 | __pblk_rl_update_rates(rl, free_blocks); | |
a4bd217b JG |
185 | } |
186 | ||
b20ba1bc | 187 | int pblk_rl_high_thrs(struct pblk_rl *rl) |
a4bd217b JG |
188 | { |
189 | return rl->high; | |
190 | } | |
191 | ||
da67e68f JG |
192 | int pblk_rl_max_io(struct pblk_rl *rl) |
193 | { | |
194 | return rl->rb_max_io; | |
195 | } | |
196 | ||
87c1d2d3 | 197 | static void pblk_rl_u_timer(struct timer_list *t) |
a4bd217b | 198 | { |
87c1d2d3 | 199 | struct pblk_rl *rl = from_timer(rl, t, u_timer); |
a4bd217b JG |
200 | |
201 | /* Release user I/O state. Protect from GC */ | |
202 | smp_store_release(&rl->rb_user_active, 0); | |
203 | } | |
204 | ||
205 | void pblk_rl_free(struct pblk_rl *rl) | |
206 | { | |
207 | del_timer(&rl->u_timer); | |
208 | } | |
209 | ||
b4cdc426 | 210 | void pblk_rl_init(struct pblk_rl *rl, int budget, int threshold) |
a4bd217b | 211 | { |
b20ba1bc | 212 | struct pblk *pblk = container_of(rl, struct pblk, rl); |
a7689938 JG |
213 | struct nvm_tgt_dev *dev = pblk->dev; |
214 | struct nvm_geo *geo = &dev->geo; | |
215 | struct pblk_line_mgmt *l_mg = &pblk->l_mg; | |
b20ba1bc | 216 | struct pblk_line_meta *lm = &pblk->lm; |
a7689938 | 217 | int sec_meta, blk_meta; |
a4bd217b JG |
218 | unsigned int rb_windows; |
219 | ||
a7689938 JG |
220 | /* Consider sectors used for metadata */ |
221 | sec_meta = (lm->smeta_sec + lm->emeta_sec[0]) * l_mg->nr_free_lines; | |
e46f4e48 | 222 | blk_meta = DIV_ROUND_UP(sec_meta, geo->clba); |
a4bd217b | 223 | |
a7689938 JG |
224 | rl->high = pblk->op_blks - blk_meta - lm->blk_per_line; |
225 | rl->high_pw = get_count_order(rl->high); | |
b20ba1bc | 226 | |
3bcebc5b | 227 | rl->rsv_blocks = pblk_get_min_chks(pblk); |
b20ba1bc | 228 | |
a4bd217b | 229 | /* This will always be a power-of-2 */ |
afdc23c9 | 230 | rb_windows = budget / NVM_MAX_VLBA; |
b20ba1bc | 231 | rl->rb_windows_pw = get_count_order(rb_windows); |
a4bd217b JG |
232 | |
233 | /* To start with, all buffer is available to user I/O writers */ | |
234 | rl->rb_budget = budget; | |
235 | rl->rb_user_max = budget; | |
a4bd217b JG |
236 | rl->rb_gc_max = 0; |
237 | rl->rb_state = PBLK_RL_HIGH; | |
588726d3 | 238 | |
9205e449 JG |
239 | /* Maximize I/O size and ansure that back threshold is respected */ |
240 | if (threshold) | |
241 | rl->rb_max_io = budget - pblk->min_write_pgs_data - threshold; | |
242 | else | |
243 | rl->rb_max_io = budget - pblk->min_write_pgs_data - 1; | |
244 | ||
588726d3 | 245 | atomic_set(&rl->rb_user_cnt, 0); |
a4bd217b | 246 | atomic_set(&rl->rb_gc_cnt, 0); |
588726d3 | 247 | atomic_set(&rl->rb_space, -1); |
48b8d208 | 248 | atomic_set(&rl->werr_lines, 0); |
a4bd217b | 249 | |
87c1d2d3 | 250 | timer_setup(&rl->u_timer, pblk_rl_u_timer, 0); |
b20ba1bc | 251 | |
a4bd217b | 252 | rl->rb_user_active = 0; |
b20ba1bc | 253 | rl->rb_gc_active = 0; |
a4bd217b | 254 | } |