From be572c7619785409f7f5efb11bc7a64405d5b1b4 Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@suse.com>
Date: Fri, 7 Feb 2025 01:20:55 +0900
Subject: [PATCH] btrfs: avoid monopolizing a core when activating a swap file
commit 2c8507c63f5498d4ee4af404a8e44ceae4345056 upstream.
This commit re-attempts the backport of the change to the linux-6.1.y
branch. Commit bb8e287f596b ("btrfs: avoid monopolizing a core when
activating a swap file") on this branch was reverted.
During swap activation we iterate over the extents of a file and we can
have many thousands of them, so we can end up in a busy loop monopolizing
a core. Avoid this by doing a voluntary reschedule after processing each
extent.
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/inode.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f4a754d62bf45..a13ab3abef122 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -11368,6 +11368,8 @@ static int btrfs_swap_activate(struct swap_info_struct *sis, struct file *file,
}
start += len;
+
+ cond_resched();
}
if (bsi.block_len)
--
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