block/blk-cgroup-rwstat.h

   1 /* SPDX-License-Identifier: GPL-2.0
   2  *
   3  * Legacy blkg rwstat helpers enabled by CONFIG_BLK_CGROUP_RWSTAT.
   4  * Do not use in new code.
   5  */
   6 #ifndef _BLK_CGROUP_RWSTAT_H
   7 #define _BLK_CGROUP_RWSTAT_H
   8
   9 #include <linux/blk-cgroup.h>
  10
  11 enum blkg_rwstat_type {
  12         BLKG_RWSTAT_READ,
  13         BLKG_RWSTAT_WRITE,
  14         BLKG_RWSTAT_SYNC,
  15         BLKG_RWSTAT_ASYNC,
  16         BLKG_RWSTAT_DISCARD,
  17
  18         BLKG_RWSTAT_NR,
  19         BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
  20 };
  21
  22 /*
  23  * blkg_[rw]stat->aux_cnt is excluded for local stats but included for
  24  * recursive.  Used to carry stats of dead children.
  25  */
  26 struct blkg_rwstat {
  27         struct percpu_counter           cpu_cnt[BLKG_RWSTAT_NR];
  28         atomic64_t                      aux_cnt[BLKG_RWSTAT_NR];
  29 };
  30
  31 struct blkg_rwstat_sample {
  32         u64                             cnt[BLKG_RWSTAT_NR];
  33 };
  34
  35 static inline u64 blkg_rwstat_read_counter(struct blkg_rwstat *rwstat,
  36                 unsigned int idx)
  37 {
  38         return atomic64_read(&rwstat->aux_cnt[idx]) +
  39                 percpu_counter_sum_positive(&rwstat->cpu_cnt[idx]);
  40 }
  41
  42 int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp);
  43 void blkg_rwstat_exit(struct blkg_rwstat *rwstat);
  44 u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
  45                          const struct blkg_rwstat_sample *rwstat);
  46 u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
  47                        int off);
  48 void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
  49                 int off, struct blkg_rwstat_sample *sum);
  50
  51
  52 /**
  53  * blkg_rwstat_add - add a value to a blkg_rwstat
  54  * @rwstat: target blkg_rwstat
  55  * @op: REQ_OP and flags
  56  * @val: value to add
  57  *
  58  * Add @val to @rwstat.  The counters are chosen according to @rw.  The
  59  * caller is responsible for synchronizing calls to this function.
  60  */
  61 static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
  62                                    unsigned int op, uint64_t val)
  63 {
  64         struct percpu_counter *cnt;
  65
  66         if (op_is_discard(op))
  67                 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_DISCARD];
  68         else if (op_is_write(op))
  69                 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
  70         else
  71                 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];
  72
  73         percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
  74
  75         if (op_is_sync(op))
  76                 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
  77         else
  78                 cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
  79
  80         percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
  81 }
  82
  83 /**
  84  * blkg_rwstat_read - read the current values of a blkg_rwstat
  85  * @rwstat: blkg_rwstat to read
  86  *
  87  * Read the current snapshot of @rwstat and return it in the aux counts.
  88  */
  89 static inline void blkg_rwstat_read(struct blkg_rwstat *rwstat,
  90                 struct blkg_rwstat_sample *result)
  91 {
  92         int i;
  93
  94         for (i = 0; i < BLKG_RWSTAT_NR; i++)
  95                 result->cnt[i] =
  96                         percpu_counter_sum_positive(&rwstat->cpu_cnt[i]);
  97 }
  98
  99 /**
 100  * blkg_rwstat_total - read the total count of a blkg_rwstat
 101  * @rwstat: blkg_rwstat to read
 102  *
 103  * Return the total count of @rwstat regardless of the IO direction.  This
 104  * function can be called without synchronization and takes care of u64
 105  * atomicity.
 106  */
 107 static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
 108 {
 109         struct blkg_rwstat_sample tmp = { };
 110
 111         blkg_rwstat_read(rwstat, &tmp);
 112         return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
 113 }
 114
 115 /**
 116  * blkg_rwstat_reset - reset a blkg_rwstat
 117  * @rwstat: blkg_rwstat to reset
 118  */
 119 static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
 120 {
 121         int i;
 122
 123         for (i = 0; i < BLKG_RWSTAT_NR; i++) {
 124                 percpu_counter_set(&rwstat->cpu_cnt[i], 0);
 125                 atomic64_set(&rwstat->aux_cnt[i], 0);
 126         }
 127 }
 128
 129 /**
 130  * blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count
 131  * @to: the destination blkg_rwstat
 132  * @from: the source
 133  *
 134  * Add @from's count including the aux one to @to's aux count.
 135  */
 136 static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to,
 137                                        struct blkg_rwstat *from)
 138 {
 139         u64 sum[BLKG_RWSTAT_NR];
 140         int i;
 141
 142         for (i = 0; i < BLKG_RWSTAT_NR; i++)
 143                 sum[i] = percpu_counter_sum_positive(&from->cpu_cnt[i]);
 144
 145         for (i = 0; i < BLKG_RWSTAT_NR; i++)
 146                 atomic64_add(sum[i] + atomic64_read(&from->aux_cnt[i]),
 147                              &to->aux_cnt[i]);
 148 }
 149 #endif  /* _BLK_CGROUP_RWSTAT_H */