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Date: Thu, 23 Dec 2021 12:21:39 -0800
From: Harshad Shirwadkar <harshadshirwadkar@...il.com>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, Harshad Shirwadkar <harshadshirwadkar@...il.com>
Subject: [PATCH v2 3/4] ext4: simplify updating of fast commit stats
From: Harshad Shirwadkar <harshadshirwadkar@...il.com>
Move fast commit stats updating logic to a separate function from
ext4_fc_commit(). This significantly improves readability of
ext4_fc_commit().
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@...il.com>
---
fs/ext4/ext4.h | 1 -
fs/ext4/fast_commit.c | 99 +++++++++++++++++++++++--------------------
fs/ext4/fast_commit.h | 27 ++++++------
3 files changed, 68 insertions(+), 59 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index d71485d53050..82fa51d6f145 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1747,7 +1747,6 @@ struct ext4_sb_info {
spinlock_t s_fc_lock;
struct buffer_head *s_fc_bh;
struct ext4_fc_stats s_fc_stats;
- u64 s_fc_avg_commit_time;
#ifdef CONFIG_EXT4_DEBUG
int s_fc_debug_max_replay;
#endif
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 2771adefdba0..a37384054c9e 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1075,6 +1075,32 @@ static int ext4_fc_perform_commit(journal_t *journal)
return ret;
}
+static void ext4_fc_update_stats(struct super_block *sb, int status,
+ u64 commit_time, int nblks)
+{
+ struct ext4_fc_stats *stats = &EXT4_SB(sb)->s_fc_stats;
+
+ jbd_debug(1, "Fast commit ended with status = %d", status);
+ if (status == EXT4_FC_STATUS_OK) {
+ stats->fc_num_commits++;
+ stats->fc_numblks += nblks;
+ if (likely(stats->s_fc_avg_commit_time))
+ stats->s_fc_avg_commit_time =
+ (commit_time +
+ stats->s_fc_avg_commit_time * 3) / 4;
+ else
+ stats->s_fc_avg_commit_time = commit_time;
+ } else if (status == EXT4_FC_STATUS_FAILED ||
+ status == EXT4_FC_STATUS_INELIGIBLE) {
+ if (status == EXT4_FC_STATUS_FAILED)
+ stats->fc_failed_commits++;
+ stats->fc_ineligible_commits++;
+ } else {
+ stats->fc_skipped_commits++;
+ }
+ trace_ext4_fc_commit_stop(sb, nblks, status);
+}
+
/*
* The main commit entry point. Performs a fast commit for transaction
* 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)
struct ext4_sb_info *sbi = EXT4_SB(sb);
int nblks = 0, ret, bsize = journal->j_blocksize;
int subtid = atomic_read(&sbi->s_fc_subtid);
- int reason = EXT4_FC_REASON_OK, fc_bufs_before = 0;
+ int status = EXT4_FC_STATUS_OK, fc_bufs_before = 0;
ktime_t start_time, commit_time;
trace_ext4_fc_commit_start(sb);
@@ -1104,69 +1130,52 @@ int ext4_fc_commit(journal_t *journal, tid_t commit_tid)
if (atomic_read(&sbi->s_fc_subtid) <= subtid &&
commit_tid > journal->j_commit_sequence)
goto restart_fc;
- reason = EXT4_FC_REASON_ALREADY_COMMITTED;
- goto out;
+ ext4_fc_update_stats(sb, EXT4_FC_STATUS_SKIPPED, 0, 0);
+ return 0;
} else if (ret) {
- sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
- reason = EXT4_FC_REASON_FC_START_FAILED;
- goto out;
+ /*
+ * Commit couldn't start. Just update stats and perform a
+ * full commit.
+ */
+ ext4_fc_update_stats(sb, EXT4_FC_STATUS_FAILED, 0, 0);
+ return jbd2_complete_transaction(journal, commit_tid);
}
+
/*
* After establishing journal barrier via jbd2_fc_begin_commit(), check
* if we are fast commit ineligible.
*/
if (ext4_test_mount_flag(sb, EXT4_MF_FC_INELIGIBLE)) {
- reason = EXT4_FC_REASON_INELIGIBLE;
- goto out;
+ status = EXT4_FC_STATUS_INELIGIBLE;
+ goto fallback;
}
fc_bufs_before = (sbi->s_fc_bytes + bsize - 1) / bsize;
ret = ext4_fc_perform_commit(journal);
if (ret < 0) {
- sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
- reason = EXT4_FC_REASON_FC_FAILED;
- goto out;
+ status = EXT4_FC_STATUS_FAILED;
+ goto fallback;
}
nblks = (sbi->s_fc_bytes + bsize - 1) / bsize - fc_bufs_before;
ret = jbd2_fc_wait_bufs(journal, nblks);
if (ret < 0) {
- sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
- reason = EXT4_FC_REASON_FC_FAILED;
- goto out;
+ status = EXT4_FC_STATUS_FAILED;
+ goto fallback;
}
atomic_inc(&sbi->s_fc_subtid);
- jbd2_fc_end_commit(journal);
-out:
- spin_lock(&sbi->s_fc_lock);
- if (reason != EXT4_FC_REASON_OK &&
- reason != EXT4_FC_REASON_ALREADY_COMMITTED) {
- sbi->s_fc_stats.fc_ineligible_commits++;
- } else {
- sbi->s_fc_stats.fc_num_commits++;
- sbi->s_fc_stats.fc_numblks += nblks;
- }
- spin_unlock(&sbi->s_fc_lock);
- nblks = (reason == EXT4_FC_REASON_OK) ? nblks : 0;
- trace_ext4_fc_commit_stop(sb, nblks, reason);
- commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
+ ret = jbd2_fc_end_commit(journal);
/*
- * weight the commit time higher than the average time so we don't
- * react too strongly to vast changes in the commit time
+ * weight the commit time higher than the average time so we
+ * don't react too strongly to vast changes in the commit time
*/
- if (likely(sbi->s_fc_avg_commit_time))
- sbi->s_fc_avg_commit_time = (commit_time +
- sbi->s_fc_avg_commit_time * 3) / 4;
- else
- sbi->s_fc_avg_commit_time = commit_time;
- jbd_debug(1,
- "Fast commit ended with blks = %d, reason = %d, subtid - %d",
- nblks, reason, subtid);
- if (reason == EXT4_FC_REASON_FC_FAILED)
- return jbd2_fc_end_commit_fallback(journal);
- if (reason == EXT4_FC_REASON_FC_START_FAILED ||
- reason == EXT4_FC_REASON_INELIGIBLE)
- return jbd2_complete_transaction(journal, commit_tid);
- return 0;
+ commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
+ ext4_fc_update_stats(sb, status, commit_time, nblks);
+ return ret;
+
+fallback:
+ ret = jbd2_fc_end_commit_fallback(journal);
+ ext4_fc_update_stats(sb, status, 0, 0);
+ return ret;
}
/*
@@ -2124,7 +2133,7 @@ int ext4_fc_info_show(struct seq_file *seq, void *v)
"fc stats:\n%ld commits\n%ld ineligible\n%ld numblks\n%lluus avg_commit_time\n",
stats->fc_num_commits, stats->fc_ineligible_commits,
stats->fc_numblks,
- div_u64(sbi->s_fc_avg_commit_time, 1000));
+ div_u64(stats->s_fc_avg_commit_time, 1000));
seq_puts(seq, "Ineligible reasons:\n");
for (i = 0; i < EXT4_FC_REASON_MAX; i++)
seq_printf(seq, "\"%s\":\t%d\n", fc_ineligible_reasons[i],
diff --git a/fs/ext4/fast_commit.h b/fs/ext4/fast_commit.h
index 937c381b4c85..083ad1cb705a 100644
--- a/fs/ext4/fast_commit.h
+++ b/fs/ext4/fast_commit.h
@@ -71,21 +71,19 @@ struct ext4_fc_tail {
};
/*
- * Fast commit reason codes
+ * Fast commit status codes
+ */
+enum {
+ EXT4_FC_STATUS_OK = 0,
+ EXT4_FC_STATUS_INELIGIBLE,
+ EXT4_FC_STATUS_SKIPPED,
+ EXT4_FC_STATUS_FAILED,
+};
+
+/*
+ * Fast commit ineligiblity reasons:
*/
enum {
- /*
- * Commit status codes:
- */
- EXT4_FC_REASON_OK = 0,
- EXT4_FC_REASON_INELIGIBLE,
- EXT4_FC_REASON_ALREADY_COMMITTED,
- EXT4_FC_REASON_FC_START_FAILED,
- EXT4_FC_REASON_FC_FAILED,
-
- /*
- * Fast commit ineligiblity reasons:
- */
EXT4_FC_REASON_XATTR = 0,
EXT4_FC_REASON_CROSS_RENAME,
EXT4_FC_REASON_JOURNAL_FLAG_CHANGE,
@@ -117,7 +115,10 @@ struct ext4_fc_stats {
unsigned int fc_ineligible_reason_count[EXT4_FC_REASON_MAX];
unsigned long fc_num_commits;
unsigned long fc_ineligible_commits;
+ unsigned long fc_failed_commits;
+ unsigned long fc_skipped_commits;
unsigned long fc_numblks;
+ u64 s_fc_avg_commit_time;
};
#define EXT4_FC_REPLAY_REALLOC_INCREMENT 4
--
2.34.1.307.g9b7440fafd-goog
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