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ext4: simplify updating of fast commit stats

Move fast commit stats updating logic to a separate function from ext4_fc_commit(). This significantly improves readability of ext4_fc_commit().

Harshad Shirwadkar committed 4 years ago

Commit 0915e461 parent 7bbbe243 files · +68 −59Browse files

Unified · Split

3 files
  1. fs/ext4/ext4.h +0 −1
  2. fs/ext4/fast_commit.c +54 −45
  3. fs/ext4/fast_commit.h +14 −13
fs/ext4/ext4.h+0−1
@@ -1747,7 +1747,6 @@ struct ext4_sb_info { · 1746 unmodified lines
17471747 spinlock_t s_fc_lock;
17481748 struct buffer_head *s_fc_bh;
17491749 struct ext4_fc_stats s_fc_stats;
1750− u64 s_fc_avg_commit_time;
17511750 #ifdef CONFIG_EXT4_DEBUG
17521751 int s_fc_debug_max_replay;
17531752 #endif
fs/ext4/fast_commit.c+54−45
@@ -1075,6 +1075,32 @@ out: · 1074 unmodified lines
10751075 return ret;
10761076 }
10771077
1078+static void ext4_fc_update_stats(struct super_block *sb, int status,
1079+ u64 commit_time, int nblks)
1080+{
1081+ struct ext4_fc_stats *stats = &EXT4_SB(sb)->s_fc_stats;
1082+
1083+ jbd_debug(1, "Fast commit ended with status = %d", status);
1084+ if (status == EXT4_FC_STATUS_OK) {
1085+ stats->fc_num_commits++;
1086+ stats->fc_numblks += nblks;
1087+ if (likely(stats->s_fc_avg_commit_time))
1088+ stats->s_fc_avg_commit_time =
1089+ (commit_time +
1090+ stats->s_fc_avg_commit_time * 3) / 4;
1091+ else
1092+ stats->s_fc_avg_commit_time = commit_time;
1093+ } else if (status == EXT4_FC_STATUS_FAILED ||
1094+ status == EXT4_FC_STATUS_INELIGIBLE) {
1095+ if (status == EXT4_FC_STATUS_FAILED)
1096+ stats->fc_failed_commits++;
1097+ stats->fc_ineligible_commits++;
1098+ } else {
1099+ stats->fc_skipped_commits++;
1100+ }
1101+ trace_ext4_fc_commit_stop(sb, nblks, status);
1102+}
1103+
10781104 /*
10791105 * The main commit entry point. Performs a fast commit for transaction
10801106 * commit_tid if needed. If it's not possible to perform a fast commit
@@ -1087,7 +1113,7 @@ int ext4_fc_commit(journal_t *journal, tid_t commit_tid) · 6 unmodified lines
10871113 struct ext4_sb_info *sbi = EXT4_SB(sb);
10881114 int nblks = 0, ret, bsize = journal->j_blocksize;
10891115 int subtid = atomic_read(&sbi->s_fc_subtid);
1090− int reason = EXT4_FC_REASON_OK, fc_bufs_before = 0;
1116+ int status = EXT4_FC_STATUS_OK, fc_bufs_before = 0;
10911117 ktime_t start_time, commit_time;
10921118
10931119 trace_ext4_fc_commit_start(sb);
@@ -1104,69 +1130,52 @@ restart_fc: · 10 unmodified lines
11041130 if (atomic_read(&sbi->s_fc_subtid) <= subtid &&
11051131 commit_tid > journal->j_commit_sequence)
11061132 goto restart_fc;
1107− reason = EXT4_FC_REASON_ALREADY_COMMITTED;
1108− goto out;
1133+ ext4_fc_update_stats(sb, EXT4_FC_STATUS_SKIPPED, 0, 0);
1134+ return 0;
11091135 } else if (ret) {
1110− sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
1111− reason = EXT4_FC_REASON_FC_START_FAILED;
1112− goto out;
1136+ /*
1137+ * Commit couldn't start. Just update stats and perform a
1138+ * full commit.
1139+ */
1140+ ext4_fc_update_stats(sb, EXT4_FC_STATUS_FAILED, 0, 0);
1141+ return jbd2_complete_transaction(journal, commit_tid);
11131142 }
1143+
11141144 /*
11151145 * After establishing journal barrier via jbd2_fc_begin_commit(), check
11161146 * if we are fast commit ineligible.
11171147 */
11181148 if (ext4_test_mount_flag(sb, EXT4_MF_FC_INELIGIBLE)) {
1119− reason = EXT4_FC_REASON_INELIGIBLE;
1120− goto out;
1149+ status = EXT4_FC_STATUS_INELIGIBLE;
1150+ goto fallback;
11211151 }
11221152
11231153 fc_bufs_before = (sbi->s_fc_bytes + bsize - 1) / bsize;
11241154 ret = ext4_fc_perform_commit(journal);
11251155 if (ret < 0) {
1126− sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
1127− reason = EXT4_FC_REASON_FC_FAILED;
1128− goto out;
1156+ status = EXT4_FC_STATUS_FAILED;
1157+ goto fallback;
11291158 }
11301159 nblks = (sbi->s_fc_bytes + bsize - 1) / bsize - fc_bufs_before;
11311160 ret = jbd2_fc_wait_bufs(journal, nblks);
11321161 if (ret < 0) {
1133− sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
1134− reason = EXT4_FC_REASON_FC_FAILED;
1135− goto out;
1162+ status = EXT4_FC_STATUS_FAILED;
1163+ goto fallback;
11361164 }
11371165 atomic_inc(&sbi->s_fc_subtid);
1138− jbd2_fc_end_commit(journal);
1139−out:
1140− spin_lock(&sbi->s_fc_lock);
1141− if (reason != EXT4_FC_REASON_OK &&
1142− reason != EXT4_FC_REASON_ALREADY_COMMITTED) {
1143− sbi->s_fc_stats.fc_ineligible_commits++;
1144− } else {
1145− sbi->s_fc_stats.fc_num_commits++;
1146− sbi->s_fc_stats.fc_numblks += nblks;
1147− }
1148− spin_unlock(&sbi->s_fc_lock);
1149− nblks = (reason == EXT4_FC_REASON_OK) ? nblks : 0;
1150− trace_ext4_fc_commit_stop(sb, nblks, reason);
1151− commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1166+ ret = jbd2_fc_end_commit(journal);
11521167 /*
1153− * weight the commit time higher than the average time so we don't
1154− * react too strongly to vast changes in the commit time
1168+ * weight the commit time higher than the average time so we
1169+ * don't react too strongly to vast changes in the commit time
11551170 */
1156− if (likely(sbi->s_fc_avg_commit_time))
1157− sbi->s_fc_avg_commit_time = (commit_time +
1158− sbi->s_fc_avg_commit_time * 3) / 4;
1159− else
1160− sbi->s_fc_avg_commit_time = commit_time;
1161− jbd_debug(1,
1162− "Fast commit ended with blks = %d, reason = %d, subtid - %d",
1163− nblks, reason, subtid);
1164− if (reason == EXT4_FC_REASON_FC_FAILED)
1165− return jbd2_fc_end_commit_fallback(journal);
1166− if (reason == EXT4_FC_REASON_FC_START_FAILED ||
1167− reason == EXT4_FC_REASON_INELIGIBLE)
1168− return jbd2_complete_transaction(journal, commit_tid);
1169− return 0;
1171+ commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1172+ ext4_fc_update_stats(sb, status, commit_time, nblks);
1173+ return ret;
1174+
1175+fallback:
1176+ ret = jbd2_fc_end_commit_fallback(journal);
1177+ ext4_fc_update_stats(sb, status, 0, 0);
1178+ return ret;
11701179 }
11711180
11721181 /*
@@ -2124,7 +2133,7 @@ int ext4_fc_info_show(struct seq_file *seq, void *v) · 951 unmodified lines
21242133 "fc stats:\n%ld commits\n%ld ineligible\n%ld numblks\n%lluus avg_commit_time\n",
21252134 stats->fc_num_commits, stats->fc_ineligible_commits,
21262135 stats->fc_numblks,
2127− div_u64(sbi->s_fc_avg_commit_time, 1000));
2136+ div_u64(stats->s_fc_avg_commit_time, 1000));
21282137 seq_puts(seq, "Ineligible reasons:\n");
21292138 for (i = 0; i < EXT4_FC_REASON_MAX; i++)
21302139 seq_printf(seq, "\"%s\":\t%d\n", fc_ineligible_reasons[i],
fs/ext4/fast_commit.h+14−13
@@ -71,21 +71,19 @@ struct ext4_fc_tail { · 70 unmodified lines
7171 };
7272
7373 /*
74− * Fast commit reason codes
74+ * Fast commit status codes
75+ */
76+enum {
77+ EXT4_FC_STATUS_OK = 0,
78+ EXT4_FC_STATUS_INELIGIBLE,
79+ EXT4_FC_STATUS_SKIPPED,
80+ EXT4_FC_STATUS_FAILED,
81+};
82+
83+/*
84+ * Fast commit ineligiblity reasons:
7585 */
7686 enum {
77− /*
78− * Commit status codes:
79− */
80− EXT4_FC_REASON_OK = 0,
81− EXT4_FC_REASON_INELIGIBLE,
82− EXT4_FC_REASON_ALREADY_COMMITTED,
83− EXT4_FC_REASON_FC_START_FAILED,
84− EXT4_FC_REASON_FC_FAILED,
85−
86− /*
87− * Fast commit ineligiblity reasons:
88− */
8987 EXT4_FC_REASON_XATTR = 0,
9088 EXT4_FC_REASON_CROSS_RENAME,
9189 EXT4_FC_REASON_JOURNAL_FLAG_CHANGE,
@@ -117,7 +115,10 @@ struct ext4_fc_stats { · 25 unmodified lines
117115 unsigned int fc_ineligible_reason_count[EXT4_FC_REASON_MAX];
118116 unsigned long fc_num_commits;
119117 unsigned long fc_ineligible_commits;
118+ unsigned long fc_failed_commits;
119+ unsigned long fc_skipped_commits;
120120 unsigned long fc_numblks;
121+ u64 s_fc_avg_commit_time;
121122 };
122123
123124 #define EXT4_FC_REPLAY_REALLOC_INCREMENT 4