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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
66114cad TH |
2 | #ifndef __LINUX_BACKING_DEV_DEFS_H |
3 | #define __LINUX_BACKING_DEV_DEFS_H | |
4 | ||
5 | #include <linux/list.h> | |
52ebea74 TH |
6 | #include <linux/radix-tree.h> |
7 | #include <linux/rbtree.h> | |
66114cad TH |
8 | #include <linux/spinlock.h> |
9 | #include <linux/percpu_counter.h> | |
52ebea74 | 10 | #include <linux/percpu-refcount.h> |
66114cad TH |
11 | #include <linux/flex_proportions.h> |
12 | #include <linux/timer.h> | |
13 | #include <linux/workqueue.h> | |
d03f6cdc | 14 | #include <linux/kref.h> |
e58dd0de | 15 | #include <linux/refcount.h> |
66114cad TH |
16 | |
17 | struct page; | |
18 | struct device; | |
19 | struct dentry; | |
20 | ||
21 | /* | |
22 | * Bits in bdi_writeback.state | |
23 | */ | |
24 | enum wb_state { | |
66114cad TH |
25 | WB_registered, /* bdi_register() was done */ |
26 | WB_writeback_running, /* Writeback is in progress */ | |
d6c10f1f | 27 | WB_has_dirty_io, /* Dirty inodes on ->b_{dirty|io|more_io} */ |
aac8d41c | 28 | WB_start_all, /* nr_pages == 0 (all) work pending */ |
66114cad TH |
29 | }; |
30 | ||
4aa9c692 TH |
31 | enum wb_congested_state { |
32 | WB_async_congested, /* The async (write) queue is getting full */ | |
33 | WB_sync_congested, /* The sync queue is getting full */ | |
34 | }; | |
35 | ||
66114cad TH |
36 | enum wb_stat_item { |
37 | WB_RECLAIMABLE, | |
38 | WB_WRITEBACK, | |
39 | WB_DIRTIED, | |
40 | WB_WRITTEN, | |
41 | NR_WB_STAT_ITEMS | |
42 | }; | |
43 | ||
44 | #define WB_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) | |
45 | ||
85009b4f JA |
46 | /* |
47 | * why some writeback work was initiated | |
48 | */ | |
49 | enum wb_reason { | |
50 | WB_REASON_BACKGROUND, | |
51 | WB_REASON_VMSCAN, | |
52 | WB_REASON_SYNC, | |
53 | WB_REASON_PERIODIC, | |
54 | WB_REASON_LAPTOP_TIMER, | |
85009b4f JA |
55 | WB_REASON_FS_FREE_SPACE, |
56 | /* | |
57 | * There is no bdi forker thread any more and works are done | |
58 | * by emergency worker, however, this is TPs userland visible | |
59 | * and we'll be exposing exactly the same information, | |
60 | * so it has a mismatch name. | |
61 | */ | |
62 | WB_REASON_FORKER_THREAD, | |
97b27821 | 63 | WB_REASON_FOREIGN_FLUSH, |
85009b4f JA |
64 | |
65 | WB_REASON_MAX, | |
66 | }; | |
67 | ||
5b9cce4c TH |
68 | struct wb_completion { |
69 | atomic_t cnt; | |
70 | wait_queue_head_t *waitq; | |
71 | }; | |
72 | ||
73 | #define __WB_COMPLETION_INIT(_waitq) \ | |
74 | (struct wb_completion){ .cnt = ATOMIC_INIT(1), .waitq = (_waitq) } | |
75 | ||
76 | /* | |
77 | * If one wants to wait for one or more wb_writeback_works, each work's | |
78 | * ->done should be set to a wb_completion defined using the following | |
79 | * macro. Once all work items are issued with wb_queue_work(), the caller | |
80 | * can wait for the completion of all using wb_wait_for_completion(). Work | |
81 | * items which are waited upon aren't freed automatically on completion. | |
82 | */ | |
83 | #define WB_COMPLETION_INIT(bdi) __WB_COMPLETION_INIT(&(bdi)->wb_waitq) | |
84 | ||
85 | #define DEFINE_WB_COMPLETION(cmpl, bdi) \ | |
86 | struct wb_completion cmpl = WB_COMPLETION_INIT(bdi) | |
87 | ||
52ebea74 TH |
88 | /* |
89 | * Each wb (bdi_writeback) can perform writeback operations, is measured | |
90 | * and throttled, independently. Without cgroup writeback, each bdi | |
91 | * (bdi_writeback) is served by its embedded bdi->wb. | |
92 | * | |
93 | * On the default hierarchy, blkcg implicitly enables memcg. This allows | |
94 | * using memcg's page ownership for attributing writeback IOs, and every | |
95 | * memcg - blkcg combination can be served by its own wb by assigning a | |
96 | * dedicated wb to each memcg, which enables isolation across different | |
97 | * cgroups and propagation of IO back pressure down from the IO layer upto | |
98 | * the tasks which are generating the dirty pages to be written back. | |
99 | * | |
100 | * A cgroup wb is indexed on its bdi by the ID of the associated memcg, | |
101 | * refcounted with the number of inodes attached to it, and pins the memcg | |
102 | * and the corresponding blkcg. As the corresponding blkcg for a memcg may | |
103 | * change as blkcg is disabled and enabled higher up in the hierarchy, a wb | |
104 | * is tested for blkcg after lookup and removed from index on mismatch so | |
105 | * that a new wb for the combination can be created. | |
106 | */ | |
66114cad TH |
107 | struct bdi_writeback { |
108 | struct backing_dev_info *bdi; /* our parent bdi */ | |
109 | ||
110 | unsigned long state; /* Always use atomic bitops on this */ | |
111 | unsigned long last_old_flush; /* last old data flush */ | |
112 | ||
113 | struct list_head b_dirty; /* dirty inodes */ | |
114 | struct list_head b_io; /* parked for writeback */ | |
115 | struct list_head b_more_io; /* parked for more writeback */ | |
116 | struct list_head b_dirty_time; /* time stamps are dirty */ | |
117 | spinlock_t list_lock; /* protects the b_* lists */ | |
118 | ||
119 | struct percpu_counter stat[NR_WB_STAT_ITEMS]; | |
120 | ||
8c911f3d | 121 | unsigned long congested; /* WB_[a]sync_congested flags */ |
4aa9c692 | 122 | |
66114cad TH |
123 | unsigned long bw_time_stamp; /* last time write bw is updated */ |
124 | unsigned long dirtied_stamp; | |
125 | unsigned long written_stamp; /* pages written at bw_time_stamp */ | |
126 | unsigned long write_bandwidth; /* the estimated write bandwidth */ | |
95a46c65 | 127 | unsigned long avg_write_bandwidth; /* further smoothed write bw, > 0 */ |
66114cad TH |
128 | |
129 | /* | |
130 | * The base dirty throttle rate, re-calculated on every 200ms. | |
131 | * All the bdi tasks' dirty rate will be curbed under it. | |
132 | * @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit | |
133 | * in small steps and is much more smooth/stable than the latter. | |
134 | */ | |
135 | unsigned long dirty_ratelimit; | |
136 | unsigned long balanced_dirty_ratelimit; | |
137 | ||
138 | struct fprop_local_percpu completions; | |
139 | int dirty_exceeded; | |
85009b4f | 140 | enum wb_reason start_all_reason; |
66114cad TH |
141 | |
142 | spinlock_t work_lock; /* protects work_list & dwork scheduling */ | |
143 | struct list_head work_list; | |
144 | struct delayed_work dwork; /* work item used for writeback */ | |
52ebea74 | 145 | |
b57d74af JA |
146 | unsigned long dirty_sleep; /* last wait */ |
147 | ||
b817525a TH |
148 | struct list_head bdi_node; /* anchored at bdi->wb_list */ |
149 | ||
52ebea74 TH |
150 | #ifdef CONFIG_CGROUP_WRITEBACK |
151 | struct percpu_ref refcnt; /* used only for !root wb's */ | |
841710aa | 152 | struct fprop_local_percpu memcg_completions; |
52ebea74 TH |
153 | struct cgroup_subsys_state *memcg_css; /* the associated memcg */ |
154 | struct cgroup_subsys_state *blkcg_css; /* and blkcg */ | |
155 | struct list_head memcg_node; /* anchored at memcg->cgwb_list */ | |
156 | struct list_head blkcg_node; /* anchored at blkcg->cgwb_list */ | |
157 | ||
158 | union { | |
159 | struct work_struct release_work; | |
160 | struct rcu_head rcu; | |
161 | }; | |
162 | #endif | |
66114cad TH |
163 | }; |
164 | ||
165 | struct backing_dev_info { | |
34f8fe50 TH |
166 | u64 id; |
167 | struct rb_node rb_node; /* keyed by ->id */ | |
66114cad | 168 | struct list_head bdi_list; |
ea1754a0 | 169 | unsigned long ra_pages; /* max readahead in PAGE_SIZE units */ |
9491ae4a | 170 | unsigned long io_pages; /* max allowed IO size */ |
66114cad | 171 | |
d03f6cdc | 172 | struct kref refcnt; /* Reference counter for the structure */ |
8db378a5 | 173 | unsigned int capabilities; /* Device capabilities */ |
66114cad TH |
174 | unsigned int min_ratio; |
175 | unsigned int max_ratio, max_prop_frac; | |
176 | ||
95a46c65 TH |
177 | /* |
178 | * Sum of avg_write_bw of wbs with dirty inodes. > 0 if there are | |
179 | * any dirty wbs, which is depended upon by bdi_has_dirty(). | |
180 | */ | |
181 | atomic_long_t tot_write_bandwidth; | |
766a9d6e | 182 | |
52ebea74 | 183 | struct bdi_writeback wb; /* the root writeback info for this bdi */ |
b817525a | 184 | struct list_head wb_list; /* list of all wbs */ |
52ebea74 TH |
185 | #ifdef CONFIG_CGROUP_WRITEBACK |
186 | struct radix_tree_root cgwb_tree; /* radix tree of active cgroup wbs */ | |
3ee7e869 | 187 | struct mutex cgwb_release_mutex; /* protect shutdown of wb structs */ |
7fc5854f | 188 | struct rw_semaphore wb_switch_rwsem; /* no cgwb switch while syncing */ |
52ebea74 | 189 | #endif |
cc395d7f TH |
190 | wait_queue_head_t wb_waitq; |
191 | ||
66114cad | 192 | struct device *dev; |
6bd87eec | 193 | char dev_name[64]; |
df08c32c | 194 | struct device *owner; |
66114cad TH |
195 | |
196 | struct timer_list laptop_mode_wb_timer; | |
197 | ||
198 | #ifdef CONFIG_DEBUG_FS | |
199 | struct dentry *debug_dir; | |
66114cad TH |
200 | #endif |
201 | }; | |
202 | ||
203 | enum { | |
204 | BLK_RW_ASYNC = 0, | |
205 | BLK_RW_SYNC = 1, | |
206 | }; | |
207 | ||
492d76b2 CH |
208 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync); |
209 | void set_bdi_congested(struct backing_dev_info *bdi, int sync); | |
66114cad | 210 | |
2e898e4c GT |
211 | struct wb_lock_cookie { |
212 | bool locked; | |
213 | unsigned long flags; | |
214 | }; | |
215 | ||
21c6321f TH |
216 | #ifdef CONFIG_CGROUP_WRITEBACK |
217 | ||
218 | /** | |
219 | * wb_tryget - try to increment a wb's refcount | |
220 | * @wb: bdi_writeback to get | |
221 | */ | |
222 | static inline bool wb_tryget(struct bdi_writeback *wb) | |
223 | { | |
224 | if (wb != &wb->bdi->wb) | |
225 | return percpu_ref_tryget(&wb->refcnt); | |
226 | return true; | |
227 | } | |
228 | ||
229 | /** | |
230 | * wb_get - increment a wb's refcount | |
231 | * @wb: bdi_writeback to get | |
232 | */ | |
233 | static inline void wb_get(struct bdi_writeback *wb) | |
234 | { | |
235 | if (wb != &wb->bdi->wb) | |
236 | percpu_ref_get(&wb->refcnt); | |
237 | } | |
238 | ||
239 | /** | |
240 | * wb_put - decrement a wb's refcount | |
241 | * @wb: bdi_writeback to put | |
242 | */ | |
243 | static inline void wb_put(struct bdi_writeback *wb) | |
244 | { | |
368686a9 AR |
245 | if (WARN_ON_ONCE(!wb->bdi)) { |
246 | /* | |
247 | * A driver bug might cause a file to be removed before bdi was | |
248 | * initialized. | |
249 | */ | |
250 | return; | |
251 | } | |
252 | ||
21c6321f TH |
253 | if (wb != &wb->bdi->wb) |
254 | percpu_ref_put(&wb->refcnt); | |
255 | } | |
256 | ||
e8a7abf5 TH |
257 | /** |
258 | * wb_dying - is a wb dying? | |
259 | * @wb: bdi_writeback of interest | |
260 | * | |
261 | * Returns whether @wb is unlinked and being drained. | |
262 | */ | |
263 | static inline bool wb_dying(struct bdi_writeback *wb) | |
264 | { | |
265 | return percpu_ref_is_dying(&wb->refcnt); | |
266 | } | |
267 | ||
21c6321f TH |
268 | #else /* CONFIG_CGROUP_WRITEBACK */ |
269 | ||
270 | static inline bool wb_tryget(struct bdi_writeback *wb) | |
271 | { | |
272 | return true; | |
273 | } | |
274 | ||
275 | static inline void wb_get(struct bdi_writeback *wb) | |
276 | { | |
277 | } | |
278 | ||
279 | static inline void wb_put(struct bdi_writeback *wb) | |
280 | { | |
281 | } | |
282 | ||
e8a7abf5 TH |
283 | static inline bool wb_dying(struct bdi_writeback *wb) |
284 | { | |
285 | return false; | |
286 | } | |
287 | ||
21c6321f TH |
288 | #endif /* CONFIG_CGROUP_WRITEBACK */ |
289 | ||
66114cad | 290 | #endif /* __LINUX_BACKING_DEV_DEFS_H */ |