On Tue, May 01, 2018 at 10:54:20AM -0400, Steven Rostedt wrote: > On Tue, 1 May 2018 21:00:12 +0800 > changbin.du@xxxxxxxxx wrote: > > > From: Changbin Du <changbin.du@xxxxxxxxx> > > > > This patch add a new kernel hacking option NO_AUTO_INLINE. Selecting > > this option will make compiler not auto-inline kernel functions. By > > enabling this option, all the kernel functions (including static ones) > > will not be optimized out except those marked as inline or always_inline. > > This is useful when you are using ftrace to understand the control flow > > of kernel code or tracing some static functions. > > I'm not against this patch, but it's up to others if this gets included > or not. > > > > > Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx> > > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> > > --- > > Makefile | 6 ++++++ > > lib/Kconfig.debug | 13 +++++++++++++ > > 2 files changed, 19 insertions(+) > > > > diff --git a/Makefile b/Makefile > > index 619a85a..eb694f6 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -775,6 +775,12 @@ KBUILD_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \ > > $(call cc-option,-fno-var-tracking) > > endif > > > > +ifdef CONFIG_NO_AUTO_INLINE > > +KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions) \ > > + $(call cc-option, -fno-inline-small-functions) \ > > + $(call cc-option, -fno-inline-functions-called-once) > > +endif > > + > > ifdef CONFIG_FUNCTION_TRACER > > ifndef CC_FLAGS_FTRACE > > CC_FLAGS_FTRACE := -pg > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index c40c7b7..90f35ad 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -198,6 +198,19 @@ config GDB_SCRIPTS > > instance. See Documentation/dev-tools/gdb-kernel-debugging.rst > > for further details. > > > > +config NO_AUTO_INLINE > > + bool "Disable compiler atuo-inline optimizations" > > typo: s/atuo/auto/ > > > + default n > > + help > > + This will make compiler not auto-inline kernel functions for > > + optimization. By enabling this option, all the kernel functions > > + (including static ones) will not be optimized out except those > > + marked as inline or always_inline. This is useful when you are > > + using ftrace to understand the control flow of kernel code or > > + tracing some static functions. > > Some grammar updates: > > This will prevent the compiler from optimizing the kernel by > auto-inlining functions not marked with the inline keyword. > With this option, only functions explicitly marked with > "inline" will be inlined. This will allow the function tracer > to trace more functions because it only traces functions that > the compiler has not inlined. > > Enabling this function can help debugging a kernel if using > the function tracer. But it can also change how the kernel > works, because inlining functions may change the timing, > which could make it difficult while debugging race conditions. > Thanks for your kind grammar updates. I will update them. :) > > + > > + Use only if you want to debug the kernel. > > The proper way to say the above is: > > If unsure, select N > Agree. > -- Steve > > > + > > config ENABLE_WARN_DEPRECATED > > bool "Enable __deprecated logic" > > default y > -- Thanks, Changbin Du -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
