Re: [PATCH v2 1/3] btrfs: tree-checker: Fix false panic for sanity test

[David Sterba <dsterba@suse.cz>]

On Wed, Nov 08, 2017 at 04:03:35PM +0800, Qu Wenruo wrote:
> >> +int btrfs_check_leaf_full(struct btrfs_root *root, struct extent_buffer *leaf)
> >> +{
> >> +	return check_leaf(root, leaf, true);
> >> +}
> >> +
> >> +int btrfs_check_leaf_relaxed(struct btrfs_root *root,
> >> +			     struct extent_buffer *leaf)
> >> +{
> >> +	return check_leaf(root, leaf, false);
> >> +}
> > 
> > Presumably the compiler will figure it out but such trivial function are
> > usually defined straight into the header file so that the compiler
> > inlines them.
> 
> In that case, the function check_leaf() must be exported, so that we can
> inline it in header.
> 
> But exporting check_leaf() increases the possibility for caller to use
> it incorrectly, so I prefer no to export any internal used function.
> 
> 
> And compiler may or may not inline check_leaf() into
> btrfs_check_leaf_relaxed() function, but it doesn't matter.
> 
> If optimization can be done by compiler, then let compiler to do it.
> 
> What we should do is to ensure the abstraction/interface design is good
> enough, other than doing possible "over-optimization".

Though my original idea was closer to what Nikolay says, I'm fine with
the way you've actually implement it. We don't need the extended
check_leaf version that's hidden in the .c file.

The function inlining possibilities will be limited, but this is not a
performance critical code where the effects of inlining could be
observale in practice (I think, no numbers to back that).