On Fri, Feb 18, 2022 at 12:15 AM David Laight <david.lai...@aculab.com> wrote: > > From: Christophe Leroy > > Sent: 17 February 2022 14:55 > > > > Le 17/02/2022 à 15:50, Christophe Leroy a écrit : > > > Adding Ingo, Andrew and Nick as they were involved in the subjet, > > > > > > Le 17/02/2022 à 14:36, David Laight a écrit : > > >> From: Christophe Leroy > > >>> Sent: 17 February 2022 12:19 > > >>> > > >>> All functions defined as static inline in net/checksum.h are > > >>> meant to be inlined for performance reason. > > >>> > > >>> But since commit ac7c3e4ff401 ("compiler: enable > > >>> CONFIG_OPTIMIZE_INLINING forcibly") the compiler is allowed to > > >>> uninline functions when it wants. > > >>> > > >>> Fair enough in the general case, but for tiny performance critical > > >>> checksum helpers that's counter-productive. > > >> > > >> There isn't a real justification for allowing the compiler > > >> to 'not inline' functions in that commit. > > > > > > Do you mean that the two following commits should be reverted: > > > > > > - 889b3c1245de ("compiler: remove CONFIG_OPTIMIZE_INLINING entirely") > > > - 4c4e276f6491 ("net: Force inlining of checksum functions in > > > net/checksum.h") > > > > Of course not the above one (copy/paste error), but: > > - ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly") > > That's the one I looked at.
No. Not that one. The commit you presumably want to revert is: a771f2b82aa2 ("[PATCH] Add a section about inlining to Documentation/CodingStyle") This is now referred to as "__always_inline disease", though. CONFIG_OPTIMIZE_INLINING has 14 years of history for x86. See commit 60a3cdd06394 ("x86: add optimized inlining"). We always give gcc freedom to not inline functions marked as inline. -- Best Regards Masahiro Yamada