Re: [PATCH] btrfs: make btrfs_node_key static inline
From: Su Yue <hidden>
Date: 2021-09-14 14:17:42
On Tue 14 Sep 2021 at 15:12, David Sterba [off-list ref] wrote:
On Tue, Sep 14, 2021 at 06:53:35PM +0800, Su Yue wrote:quoted
It looks strange that btrfs_node_key is in struct-funcs.c. So move it to ctree.h and make it static inline."looks strange" is not a sufficient reason. Inlining a function means that the body will be expanded at each call site, bloating the binary code. Have you measured the impact of that?
Fair enough. Before: text data bss dec hex filename 1202418 123105 19384 1344907 14858b fs/btrfs/btrfs.ko After: text data bss dec hex filename 1202620 123105 19384 1345109 148655 fs/btrfs/btrfs.ko +202
There's some performance cost of an non-inline function due to the call overhead but it does not make sense to inline a function that's called rarely and not in a tight loop. If you grep for the function you'd see that it's called eg. once per function or in a loop that's not performance critical on first sight (eg. in reada_for_search).
Right, the patch won't impact performance obviously at the cost of +202 binary size. So I'd drop the patch. Sorry for the noise. -- Su