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a7b36ee6 JA |
1 | #ifndef BLK_THROTTLE_H |
2 | #define BLK_THROTTLE_H | |
3 | ||
4 | #include "blk-cgroup-rwstat.h" | |
5 | ||
6 | /* | |
7 | * To implement hierarchical throttling, throtl_grps form a tree and bios | |
8 | * are dispatched upwards level by level until they reach the top and get | |
9 | * issued. When dispatching bios from the children and local group at each | |
10 | * level, if the bios are dispatched into a single bio_list, there's a risk | |
11 | * of a local or child group which can queue many bios at once filling up | |
12 | * the list starving others. | |
13 | * | |
14 | * To avoid such starvation, dispatched bios are queued separately | |
15 | * according to where they came from. When they are again dispatched to | |
16 | * the parent, they're popped in round-robin order so that no single source | |
17 | * hogs the dispatch window. | |
18 | * | |
19 | * throtl_qnode is used to keep the queued bios separated by their sources. | |
20 | * Bios are queued to throtl_qnode which in turn is queued to | |
21 | * throtl_service_queue and then dispatched in round-robin order. | |
22 | * | |
23 | * It's also used to track the reference counts on blkg's. A qnode always | |
24 | * belongs to a throtl_grp and gets queued on itself or the parent, so | |
25 | * incrementing the reference of the associated throtl_grp when a qnode is | |
26 | * queued and decrementing when dequeued is enough to keep the whole blkg | |
27 | * tree pinned while bios are in flight. | |
28 | */ | |
29 | struct throtl_qnode { | |
30 | struct list_head node; /* service_queue->queued[] */ | |
31 | struct bio_list bios; /* queued bios */ | |
32 | struct throtl_grp *tg; /* tg this qnode belongs to */ | |
33 | }; | |
34 | ||
35 | struct throtl_service_queue { | |
36 | struct throtl_service_queue *parent_sq; /* the parent service_queue */ | |
37 | ||
38 | /* | |
39 | * Bios queued directly to this service_queue or dispatched from | |
40 | * children throtl_grp's. | |
41 | */ | |
42 | struct list_head queued[2]; /* throtl_qnode [READ/WRITE] */ | |
43 | unsigned int nr_queued[2]; /* number of queued bios */ | |
44 | ||
45 | /* | |
46 | * RB tree of active children throtl_grp's, which are sorted by | |
47 | * their ->disptime. | |
48 | */ | |
49 | struct rb_root_cached pending_tree; /* RB tree of active tgs */ | |
50 | unsigned int nr_pending; /* # queued in the tree */ | |
51 | unsigned long first_pending_disptime; /* disptime of the first tg */ | |
52 | struct timer_list pending_timer; /* fires on first_pending_disptime */ | |
53 | }; | |
54 | ||
5a93b602 ML |
55 | enum tg_state_flags { |
56 | THROTL_TG_PENDING = 1 << 0, /* on parent's pending tree */ | |
57 | THROTL_TG_WAS_EMPTY = 1 << 1, /* bio_lists[] became non-empty */ | |
85496749 | 58 | THROTL_TG_CANCELING = 1 << 2, /* starts to cancel bio */ |
5a93b602 ML |
59 | }; |
60 | ||
a7b36ee6 JA |
61 | struct throtl_grp { |
62 | /* must be the first member */ | |
63 | struct blkg_policy_data pd; | |
64 | ||
65 | /* active throtl group service_queue member */ | |
66 | struct rb_node rb_node; | |
67 | ||
68 | /* throtl_data this group belongs to */ | |
69 | struct throtl_data *td; | |
70 | ||
71 | /* this group's service queue */ | |
72 | struct throtl_service_queue service_queue; | |
73 | ||
74 | /* | |
75 | * qnode_on_self is used when bios are directly queued to this | |
76 | * throtl_grp so that local bios compete fairly with bios | |
77 | * dispatched from children. qnode_on_parent is used when bios are | |
78 | * dispatched from this throtl_grp into its parent and will compete | |
79 | * with the sibling qnode_on_parents and the parent's | |
80 | * qnode_on_self. | |
81 | */ | |
82 | struct throtl_qnode qnode_on_self[2]; | |
83 | struct throtl_qnode qnode_on_parent[2]; | |
84 | ||
85 | /* | |
86 | * Dispatch time in jiffies. This is the estimated time when group | |
87 | * will unthrottle and is ready to dispatch more bio. It is used as | |
88 | * key to sort active groups in service tree. | |
89 | */ | |
90 | unsigned long disptime; | |
91 | ||
92 | unsigned int flags; | |
93 | ||
94 | /* are there any throtl rules between this group and td? */ | |
81c7a63a YK |
95 | bool has_rules_bps[2]; |
96 | bool has_rules_iops[2]; | |
a7b36ee6 JA |
97 | |
98 | /* internally used bytes per second rate limits */ | |
bf20ab53 | 99 | uint64_t bps[2]; |
a7b36ee6 | 100 | /* user configured bps limits */ |
bf20ab53 | 101 | uint64_t bps_conf[2]; |
a7b36ee6 JA |
102 | |
103 | /* internally used IOPS limits */ | |
bf20ab53 | 104 | unsigned int iops[2]; |
a7b36ee6 | 105 | /* user configured IOPS limits */ |
bf20ab53 | 106 | unsigned int iops_conf[2]; |
a7b36ee6 JA |
107 | |
108 | /* Number of bytes dispatched in current slice */ | |
109 | uint64_t bytes_disp[2]; | |
110 | /* Number of bio's dispatched in current slice */ | |
111 | unsigned int io_disp[2]; | |
112 | ||
113 | unsigned long last_low_overflow_time[2]; | |
114 | ||
115 | uint64_t last_bytes_disp[2]; | |
116 | unsigned int last_io_disp[2]; | |
117 | ||
a880ae93 YK |
118 | /* |
119 | * The following two fields are updated when new configuration is | |
120 | * submitted while some bios are still throttled, they record how many | |
121 | * bytes/ios are waited already in previous configuration, and they will | |
122 | * be used to calculate wait time under new configuration. | |
123 | */ | |
ef100397 YK |
124 | long long carryover_bytes[2]; |
125 | int carryover_ios[2]; | |
a880ae93 | 126 | |
a7b36ee6 JA |
127 | unsigned long last_check_time; |
128 | ||
a7b36ee6 JA |
129 | /* When did we start a new slice */ |
130 | unsigned long slice_start[2]; | |
131 | unsigned long slice_end[2]; | |
132 | ||
a7b36ee6 JA |
133 | struct blkg_rwstat stat_bytes; |
134 | struct blkg_rwstat stat_ios; | |
135 | }; | |
136 | ||
137 | extern struct blkcg_policy blkcg_policy_throtl; | |
138 | ||
139 | static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) | |
140 | { | |
141 | return pd ? container_of(pd, struct throtl_grp, pd) : NULL; | |
142 | } | |
143 | ||
144 | static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg) | |
145 | { | |
146 | return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl)); | |
147 | } | |
148 | ||
149 | /* | |
150 | * Internal throttling interface | |
151 | */ | |
152 | #ifndef CONFIG_BLK_DEV_THROTTLING | |
e13793ba | 153 | static inline void blk_throtl_exit(struct gendisk *disk) { } |
a7b36ee6 | 154 | static inline bool blk_throtl_bio(struct bio *bio) { return false; } |
cad9266a | 155 | static inline void blk_throtl_cancel_bios(struct gendisk *disk) { } |
a7b36ee6 | 156 | #else /* CONFIG_BLK_DEV_THROTTLING */ |
e13793ba | 157 | void blk_throtl_exit(struct gendisk *disk); |
a7b36ee6 | 158 | bool __blk_throtl_bio(struct bio *bio); |
cad9266a | 159 | void blk_throtl_cancel_bios(struct gendisk *disk); |
81c7a63a | 160 | |
a3166c51 YK |
161 | static inline bool blk_throtl_activated(struct request_queue *q) |
162 | { | |
163 | return q->td != NULL; | |
164 | } | |
165 | ||
81c7a63a | 166 | static inline bool blk_should_throtl(struct bio *bio) |
a7b36ee6 | 167 | { |
a3166c51 | 168 | struct throtl_grp *tg; |
81c7a63a YK |
169 | int rw = bio_data_dir(bio); |
170 | ||
a3166c51 YK |
171 | /* |
172 | * This is called under bio_queue_enter(), and it's synchronized with | |
173 | * the activation of blk-throtl, which is protected by | |
174 | * blk_mq_freeze_queue(). | |
175 | */ | |
176 | if (!blk_throtl_activated(bio->bi_bdev->bd_queue)) | |
177 | return false; | |
178 | ||
179 | tg = blkg_to_tg(bio->bi_blkg); | |
ad7c3b41 JH |
180 | if (!cgroup_subsys_on_dfl(io_cgrp_subsys)) { |
181 | if (!bio_flagged(bio, BIO_CGROUP_ACCT)) { | |
182 | bio_set_flag(bio, BIO_CGROUP_ACCT); | |
183 | blkg_rwstat_add(&tg->stat_bytes, bio->bi_opf, | |
184 | bio->bi_iter.bi_size); | |
185 | } | |
186 | blkg_rwstat_add(&tg->stat_ios, bio->bi_opf, 1); | |
187 | } | |
188 | ||
81c7a63a YK |
189 | /* iops limit is always counted */ |
190 | if (tg->has_rules_iops[rw]) | |
191 | return true; | |
192 | ||
193 | if (tg->has_rules_bps[rw] && !bio_flagged(bio, BIO_BPS_THROTTLED)) | |
194 | return true; | |
195 | ||
196 | return false; | |
197 | } | |
198 | ||
199 | static inline bool blk_throtl_bio(struct bio *bio) | |
200 | { | |
a7b36ee6 | 201 | |
81c7a63a | 202 | if (!blk_should_throtl(bio)) |
a7b36ee6 JA |
203 | return false; |
204 | ||
205 | return __blk_throtl_bio(bio); | |
206 | } | |
207 | #endif /* CONFIG_BLK_DEV_THROTTLING */ | |
208 | ||
209 | #endif |