On Mon, 8 Jan 2024, Vladimir Oltean wrote: ... > Nitpick: you could render this in kernel-doc format. > https://docs.kernel.org/doc-guide/kernel-doc.html > > > +static inline bool stmmac_has_ip_ethertype(struct sk_buff *skb) > > Nitpick: in netdev it is preferred not to use the "inline" keyword at > all in C files, only "static inline" in headers, and to let the compiler > decide by itself when it is appropriate to inline the code (which it > does by itself even without the "inline" keyword). For a bit more > background why, you can view Documentation/process/4.Coding.rst, section > "Inline functions". I see, the kernel docs were indeed enlightening on this point. As a side note, I've just benchmarked both the "with-inline" and "without-inline" versions. First of all, objdump seems to confirm that GCC does indeed follow this pragma in this particular case. Also, RX perfs are better with stmmac_has_ip_ethertype inlined, but TX perfs are actually consistently worse with this function inlined, which could very well be caused by cache effects. In any case, I think it is better to remove the "inline" pragma as you said. I'll do that in v4. Best Regards, -- Romain Gantois, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
