125 lines · c
1/* SPDX-License-Identifier: GPL-2.02 *3 * Legacy blkg rwstat helpers enabled by CONFIG_BLK_CGROUP_RWSTAT.4 * Do not use in new code.5 */6#include "blk-cgroup-rwstat.h"7 8int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)9{10 int i, ret;11 12 ret = percpu_counter_init_many(rwstat->cpu_cnt, 0, gfp, BLKG_RWSTAT_NR);13 if (ret)14 return ret;15 16 for (i = 0; i < BLKG_RWSTAT_NR; i++)17 atomic64_set(&rwstat->aux_cnt[i], 0);18 return 0;19}20EXPORT_SYMBOL_GPL(blkg_rwstat_init);21 22void blkg_rwstat_exit(struct blkg_rwstat *rwstat)23{24 percpu_counter_destroy_many(rwstat->cpu_cnt, BLKG_RWSTAT_NR);25}26EXPORT_SYMBOL_GPL(blkg_rwstat_exit);27 28/**29 * __blkg_prfill_rwstat - prfill helper for a blkg_rwstat30 * @sf: seq_file to print to31 * @pd: policy private data of interest32 * @rwstat: rwstat to print33 *34 * Print @rwstat to @sf for the device assocaited with @pd.35 */36u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,37 const struct blkg_rwstat_sample *rwstat)38{39 static const char *rwstr[] = {40 [BLKG_RWSTAT_READ] = "Read",41 [BLKG_RWSTAT_WRITE] = "Write",42 [BLKG_RWSTAT_SYNC] = "Sync",43 [BLKG_RWSTAT_ASYNC] = "Async",44 [BLKG_RWSTAT_DISCARD] = "Discard",45 };46 const char *dname = blkg_dev_name(pd->blkg);47 u64 v;48 int i;49 50 if (!dname)51 return 0;52 53 for (i = 0; i < BLKG_RWSTAT_NR; i++)54 seq_printf(sf, "%s %s %llu\n", dname, rwstr[i],55 rwstat->cnt[i]);56 57 v = rwstat->cnt[BLKG_RWSTAT_READ] +58 rwstat->cnt[BLKG_RWSTAT_WRITE] +59 rwstat->cnt[BLKG_RWSTAT_DISCARD];60 seq_printf(sf, "%s Total %llu\n", dname, v);61 return v;62}63EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat);64 65/**66 * blkg_prfill_rwstat - prfill callback for blkg_rwstat67 * @sf: seq_file to print to68 * @pd: policy private data of interest69 * @off: offset to the blkg_rwstat in @pd70 *71 * prfill callback for printing a blkg_rwstat.72 */73u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,74 int off)75{76 struct blkg_rwstat_sample rwstat = { };77 78 blkg_rwstat_read((void *)pd + off, &rwstat);79 return __blkg_prfill_rwstat(sf, pd, &rwstat);80}81EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);82 83/**84 * blkg_rwstat_recursive_sum - collect hierarchical blkg_rwstat85 * @blkg: blkg of interest86 * @pol: blkcg_policy which contains the blkg_rwstat87 * @off: offset to the blkg_rwstat in blkg_policy_data or @blkg88 * @sum: blkg_rwstat_sample structure containing the results89 *90 * Collect the blkg_rwstat specified by @blkg, @pol and @off and all its91 * online descendants and their aux counts. The caller must be holding the92 * queue lock for online tests.93 *94 * If @pol is NULL, blkg_rwstat is at @off bytes into @blkg; otherwise, it95 * is at @off bytes into @blkg's blkg_policy_data of the policy.96 */97void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,98 int off, struct blkg_rwstat_sample *sum)99{100 struct blkcg_gq *pos_blkg;101 struct cgroup_subsys_state *pos_css;102 unsigned int i;103 104 lockdep_assert_held(&blkg->q->queue_lock);105 106 memset(sum, 0, sizeof(*sum));107 rcu_read_lock();108 blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {109 struct blkg_rwstat *rwstat;110 111 if (!pos_blkg->online)112 continue;113 114 if (pol)115 rwstat = (void *)blkg_to_pd(pos_blkg, pol) + off;116 else117 rwstat = (void *)pos_blkg + off;118 119 for (i = 0; i < BLKG_RWSTAT_NR; i++)120 sum->cnt[i] += blkg_rwstat_read_counter(rwstat, i);121 }122 rcu_read_unlock();123}124EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum);125