forked from mirrors/linux
		
	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(). Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com> Link: https://lore.kernel.org/r/20211223202140.2061101-4-harshads@google.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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					 3 changed files with 67 additions and 58 deletions
				
			
		|  | @ -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 | ||||
|  |  | |||
|  | @ -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], | ||||
|  |  | |||
|  | @ -71,21 +71,19 @@ struct ext4_fc_tail { | |||
| }; | ||||
| 
 | ||||
| /*
 | ||||
|  * Fast commit reason codes | ||||
|  * Fast commit status codes | ||||
|  */ | ||||
| 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, | ||||
| 	EXT4_FC_STATUS_OK = 0, | ||||
| 	EXT4_FC_STATUS_INELIGIBLE, | ||||
| 	EXT4_FC_STATUS_SKIPPED, | ||||
| 	EXT4_FC_STATUS_FAILED, | ||||
| }; | ||||
| 
 | ||||
| 	/*
 | ||||
| 	 * Fast commit ineligiblity reasons: | ||||
| 	 */ | ||||
| /*
 | ||||
|  * Fast commit ineligiblity reasons: | ||||
|  */ | ||||
| enum { | ||||
| 	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 | ||||
|  |  | |||
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	 Harshad Shirwadkar
						Harshad Shirwadkar