linux-kernel - [PATCH 15/21] ext4: use best found when complex scan of group finishs

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Date:   Fri, 10 Feb 2023 03:48:19 +0800
From:   Kemeng Shi <shikemeng@...weicloud.com>
To:     tytso@....edu, adilger.kernel@...ger.ca, jack@...e.cz
Cc:     linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 15/21] ext4: use best found when complex scan of group finishs

If any bex which meets bex->fe_len >= gex->fe_len is found, then it will
always be used when complex scan of group that bex belongs to finishs.
So there will not be any lock-unlock period.

Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
---
 fs/ext4/mballoc.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index e53f84de5018..c684758d6dbb 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2019,8 +2019,6 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
 	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
 	struct ext4_free_extent *bex = &ac->ac_b_ex;
 	struct ext4_free_extent *gex = &ac->ac_g_ex;
-	struct ext4_free_extent ex;
-	int max;
 
 	if (ac->ac_status == AC_STATUS_FOUND)
 		return;
@@ -2039,16 +2037,8 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
 	if (bex->fe_len < gex->fe_len)
 		return;
 
-	if (finish_group && bex->fe_group == e4b->bd_group) {
-		/* recheck chunk's availability - we don't know
-		 * when it was found (within this lock-unlock
-		 * period or not) */
-		max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
-		if (max >= gex->fe_len) {
-			ext4_mb_use_best_found(ac, e4b);
-			return;
-		}
-	}
+	if (finish_group)
+		ext4_mb_use_best_found(ac, e4b);
 }
 
 /*
-- 
2.30.0