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