From: Filipe Manana <fdmanana@xxxxxxxx> commit 2c8507c63f5498d4ee4af404a8e44ceae4345056 upstream. 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@xxxxxxxxxxxxxxx # 5.4+ Reviewed-by: Qu Wenruo <wqu@xxxxxxxx> Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/inode.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7679,6 +7679,8 @@ noinline int can_nocow_extent(struct ino ret = -EAGAIN; goto out; } + + cond_resched(); } btrfs_release_path(path); Patches currently in stable-queue which might be from fdmanana@xxxxxxxx are queue-5.4/btrfs-tree-checker-reject-inline-extent-items-with-0-ref-count.patch queue-5.4/btrfs-avoid-monopolizing-a-core-when-activating-a-swap-file.patch
