linux-kernel - [PATCH] ext4: add cond_resched() to ext4_mb_init

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Date:   Mon, 15 Apr 2019 19:59:34 -0700
From:   Khazhismel Kumykov <khazhy@...gle.com>
To:     tytso@....edu, adilger.kernel@...ger.ca
Cc:     linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
        Khazhismel Kumykov <khazhy@...gle.com>
Subject: [PATCH] ext4: add cond_resched() to ext4_mb_init_backend()

on non-preempt kernels for filesystems with large number of groups we
may take a long time (>50 ticks) initializing all the groups.

Signed-off-by: Khazhismel Kumykov <khazhy@...gle.com>
---
 fs/ext4/mballoc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 8ef5f12bbee2..c89f497ccf50 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2490,6 +2490,7 @@ static int ext4_mb_init_backend(struct super_block *sb)
 	sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
 	EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
 	for (i = 0; i < ngroups; i++) {
+		cond_resched();
 		desc = ext4_get_group_desc(sb, i, NULL);
 		if (desc == NULL) {
 			ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
-- 
2.21.0.392.gf8f6787159e-goog