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-rw-r--r--block/blk-cgroup-rwstat.h149
1 files changed, 149 insertions, 0 deletions
diff --git a/block/blk-cgroup-rwstat.h b/block/blk-cgroup-rwstat.h
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index 000000000..022527b0b
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+++ b/block/blk-cgroup-rwstat.h
@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Legacy blkg rwstat helpers enabled by CONFIG_BLK_CGROUP_RWSTAT.
+ * Do not use in new code.
+ */
+#ifndef _BLK_CGROUP_RWSTAT_H
+#define _BLK_CGROUP_RWSTAT_H
+
+#include "blk-cgroup.h"
+
+enum blkg_rwstat_type {
+ BLKG_RWSTAT_READ,
+ BLKG_RWSTAT_WRITE,
+ BLKG_RWSTAT_SYNC,
+ BLKG_RWSTAT_ASYNC,
+ BLKG_RWSTAT_DISCARD,
+
+ BLKG_RWSTAT_NR,
+ BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
+};
+
+/*
+ * blkg_[rw]stat->aux_cnt is excluded for local stats but included for
+ * recursive. Used to carry stats of dead children.
+ */
+struct blkg_rwstat {
+ struct percpu_counter cpu_cnt[BLKG_RWSTAT_NR];
+ atomic64_t aux_cnt[BLKG_RWSTAT_NR];
+};
+
+struct blkg_rwstat_sample {
+ u64 cnt[BLKG_RWSTAT_NR];
+};
+
+static inline u64 blkg_rwstat_read_counter(struct blkg_rwstat *rwstat,
+ unsigned int idx)
+{
+ return atomic64_read(&rwstat->aux_cnt[idx]) +
+ percpu_counter_sum_positive(&rwstat->cpu_cnt[idx]);
+}
+
+int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp);
+void blkg_rwstat_exit(struct blkg_rwstat *rwstat);
+u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
+ const struct blkg_rwstat_sample *rwstat);
+u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
+ int off);
+void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
+ int off, struct blkg_rwstat_sample *sum);
+
+
+/**
+ * blkg_rwstat_add - add a value to a blkg_rwstat
+ * @rwstat: target blkg_rwstat
+ * @op: REQ_OP and flags
+ * @val: value to add
+ *
+ * Add @val to @rwstat. The counters are chosen according to @rw. The
+ * caller is responsible for synchronizing calls to this function.
+ */
+static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
+ blk_opf_t opf, uint64_t val)
+{
+ struct percpu_counter *cnt;
+
+ if (op_is_discard(opf))
+ cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_DISCARD];
+ else if (op_is_write(opf))
+ cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
+ else
+ cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];
+
+ percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
+
+ if (op_is_sync(opf))
+ cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
+ else
+ cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
+
+ percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH);
+}
+
+/**
+ * blkg_rwstat_read - read the current values of a blkg_rwstat
+ * @rwstat: blkg_rwstat to read
+ *
+ * Read the current snapshot of @rwstat and return it in the aux counts.
+ */
+static inline void blkg_rwstat_read(struct blkg_rwstat *rwstat,
+ struct blkg_rwstat_sample *result)
+{
+ int i;
+
+ for (i = 0; i < BLKG_RWSTAT_NR; i++)
+ result->cnt[i] =
+ percpu_counter_sum_positive(&rwstat->cpu_cnt[i]);
+}
+
+/**
+ * blkg_rwstat_total - read the total count of a blkg_rwstat
+ * @rwstat: blkg_rwstat to read
+ *
+ * Return the total count of @rwstat regardless of the IO direction. This
+ * function can be called without synchronization and takes care of u64
+ * atomicity.
+ */
+static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
+{
+ struct blkg_rwstat_sample tmp = { };
+
+ blkg_rwstat_read(rwstat, &tmp);
+ return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
+}
+
+/**
+ * blkg_rwstat_reset - reset a blkg_rwstat
+ * @rwstat: blkg_rwstat to reset
+ */
+static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
+{
+ int i;
+
+ for (i = 0; i < BLKG_RWSTAT_NR; i++) {
+ percpu_counter_set(&rwstat->cpu_cnt[i], 0);
+ atomic64_set(&rwstat->aux_cnt[i], 0);
+ }
+}
+
+/**
+ * blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count
+ * @to: the destination blkg_rwstat
+ * @from: the source
+ *
+ * Add @from's count including the aux one to @to's aux count.
+ */
+static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to,
+ struct blkg_rwstat *from)
+{
+ u64 sum[BLKG_RWSTAT_NR];
+ int i;
+
+ for (i = 0; i < BLKG_RWSTAT_NR; i++)
+ sum[i] = percpu_counter_sum_positive(&from->cpu_cnt[i]);
+
+ for (i = 0; i < BLKG_RWSTAT_NR; i++)
+ atomic64_add(sum[i] + atomic64_read(&from->aux_cnt[i]),
+ &to->aux_cnt[i]);
+}
+#endif /* _BLK_CGROUP_RWSTAT_H */