linux-ext4 - [PATCH v3] ext4: fix log printing of ext4_mb_regular

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Message-ID: <0a165ac0-1912-aebd-8a0d-b42e7cd1aea1@gmail.com>
Date:   Sat, 15 Aug 2020 08:10:44 +0800
From:   brookxu <brookxu.cn@...il.com>
To:     adilger.kernel@...ger.ca, tytso@....edu, linux-ext4@...r.kernel.org
Cc:     riteshh@...ux.ibm.com
Subject: [PATCH v3] ext4: fix log printing of ext4_mb_regular_allocator()

Fix log printing of ext4_mb_regular_allocator()，it may be an
unintentional behavior.

V3:
It may be better to add a comma between start and len, which is
convenient for script processing.

V2:
Add more valuable information, such as group, start, len, lost.

Signed-off-by: Chunguang Xu <brookxu@...cent.com>
---
 fs/ext4/mballoc.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index c0a331e..70b110f 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2218,6 +2218,7 @@ static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac,
 	struct ext4_sb_info *sbi;
 	struct super_block *sb;
 	struct ext4_buddy e4b;
+	unsigned int lost;
 
 	sb = ac->ac_sb;
 	sbi = EXT4_SB(sb);
@@ -2341,22 +2342,24 @@ static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac,
 		 * We've been searching too long. Let's try to allocate
 		 * the best chunk we've found so far
 		 */
-
 		ext4_mb_try_best_found(ac, &e4b);
 		if (ac->ac_status != AC_STATUS_FOUND) {
 			/*
 			 * Someone more lucky has already allocated it.
 			 * The only thing we can do is just take first
 			 * found block(s)
-			printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n");
 			 */
+			lost = (unsigned int)atomic_inc_return(&sbi->s_mb_lost_chunks);
+			mb_debug(sb, "lost chunk, group: %u, start: %d, len: %d, lost: %u\n",
+				 ac->ac_b_ex.fe_group, ac->ac_b_ex.fe_start,
+				 ac->ac_b_ex.fe_len, lost);
+
 			ac->ac_b_ex.fe_group = 0;
 			ac->ac_b_ex.fe_start = 0;
 			ac->ac_b_ex.fe_len = 0;
 			ac->ac_status = AC_STATUS_CONTINUE;
 			ac->ac_flags |= EXT4_MB_HINT_FIRST;
 			cr = 3;
-			atomic_inc(&sbi->s_mb_lost_chunks);
 			goto repeat;
 		}
 	}
-- 
1.8.3.1