From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:34134 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726617AbeIKOVh (ORCPT ); Tue, 11 Sep 2018 10:21:37 -0400 Date: Tue, 11 Sep 2018 11:22:51 +0200 From: David Sterba To: Omar Sandoval Cc: David Sterba , linux-btrfs@vger.kernel.org Subject: Re: [PATCH 4/4] btrfs: tests: polish ifdefs around testing helper Message-ID: <20180911092250.GC24025@twin.jikos.cz> Reply-To: dsterba@suse.cz References: <7a6c4814d8467999d9a9eb12906ff28a3f90b284.1536599879.git.dsterba@suse.com> <20180910234329.GD16436@vader> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20180910234329.GD16436@vader> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Mon, Sep 10, 2018 at 04:43:29PM -0700, Omar Sandoval wrote: > On Mon, Sep 10, 2018 at 07:22:31PM +0200, David Sterba wrote: > > Avoid the inline ifdefs and use two sections for self-tests enabled and > > disabled. > > > > Signed-off-by: David Sterba > > --- > > fs/btrfs/ctree.h | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > > index 32d2fce4ac53..8dafc7bb6ad8 100644 > > --- a/fs/btrfs/ctree.h > > +++ b/fs/btrfs/ctree.h > > @@ -3708,17 +3708,20 @@ static inline int btrfs_defrag_cancelled(struct btrfs_fs_info *fs_info) > > #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS > > void btrfs_test_inode_set_ops(struct inode *inode); > > void btrfs_test_destroy_inode(struct inode *inode); > > -#endif > > > > static inline int btrfs_is_testing(struct btrfs_fs_info *fs_info) > > { > > -#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS > > if (unlikely(test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, > > &fs_info->fs_state))) > > return 1; > > -#endif > > return 0; > > How about just: > > return test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state); > > We can probably get away without the unlikely() considering that no one > sane is going to run a kernel with CONFIG_BTRFS_FS_RUN_SANITY_TESTS in > production. The unlikely can go away, sure. I would still like to remove the test_bit call when tests are compiled out. There are about 10 calls to btrfs_is_testing in various core functions, followed by further statements. This would have a (negligible) runtime penalty but generates effectively unused code on production builds. The static inline function returning 0 allows to optimize out the unused code, so smaller code, fewer inctructions, etc.