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Mon, 22 Jun 2026 06:41:17 -0700 (PDT) Received: from localhost ([38.101.158.131]) by smtp.gmail.com with ESMTPSA id 00721157ae682-8025cf6703bsm31379457b3.16.2026.06.22.06.41.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jun 2026 06:41:17 -0700 (PDT) From: Yury Norov X-Google-Original-From: Yury Norov Date: Mon, 22 Jun 2026 09:41:16 -0400 To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Linus Torvalds , Sebastian Andrzej Siewior , John Ogness , Thomas Gleixner , Peter Zijlstra , Julia Lawall , Yury Norov Subject: Re: [PATCH v2 1/2] tracing: Move non-trace_printk prototypes into trace_controls.h Message-ID: References: <20260622130739.375198646@kernel.org> <20260622131029.655382134@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260622131029.655382134@kernel.org> On Mon, Jun 22, 2026 at 09:07:40AM -0400, Steven Rostedt wrote: > From: Steven Rostedt > > In order to remove the include to trace_printk.h from kernel.h the tracing > control prototypes need to be separated into their own header file as they > are used in other common header files like rcu.h. There's no point in > removing trace_printk.h from kernel.h if it just gets added back to other > common headers. > > Prototypes are very cheap for the compiler and should not be an issue. > > Signed-off-by: Steven Rostedt Suggested-by: Yury Norov > --- > Changes since v1: https://patch.msgid.link/20260621093811.007634476@kernel.org > > - Instead of moving back into kernel.h, create a new trace_controls.h > header. > > arch/powerpc/xmon/xmon.c | 1 + > arch/s390/kernel/ipl.c | 1 + > arch/s390/kernel/machine_kexec.c | 1 + > drivers/gpu/drm/i915/i915_gem.h | 1 + > drivers/tty/sysrq.c | 1 + > include/linux/trace_controls.h | 54 ++++++++++++++++++++++++++++++++ > include/linux/trace_printk.h | 51 ------------------------------ > kernel/debug/debug_core.c | 1 + > kernel/panic.c | 1 + > kernel/rcu/rcu.h | 2 ++ > kernel/rcu/rcutorture.c | 1 + > kernel/trace/trace.h | 1 + > kernel/trace/trace_benchmark.c | 1 + > lib/sys_info.c | 1 + > 14 files changed, 67 insertions(+), 51 deletions(-) > create mode 100644 include/linux/trace_controls.h > > diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c > index cb3a3244ae6f..2135f319e0dd 100644 > --- a/arch/powerpc/xmon/xmon.c > +++ b/arch/powerpc/xmon/xmon.c > @@ -27,6 +27,7 @@ > #include > #include > #include > +#include > > #include > #include > diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c > index 3c346b02ceb9..baac66cc4de4 100644 > --- a/arch/s390/kernel/ipl.c > +++ b/arch/s390/kernel/ipl.c > @@ -22,6 +22,7 @@ > #include > #include > #include > +#include > #include > #include > #include > diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c > index baeb3dcfc1c8..33f9a89eb3ad 100644 > --- a/arch/s390/kernel/machine_kexec.c > +++ b/arch/s390/kernel/machine_kexec.c > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > #include > #include > #include > diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h > index 20b3cb29cfff..1da8fb61c09e 100644 > --- a/drivers/gpu/drm/i915/i915_gem.h > +++ b/drivers/gpu/drm/i915/i915_gem.h > @@ -116,6 +116,7 @@ int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file); > #endif > > #if IS_ENABLED(CONFIG_DRM_I915_TRACE_GEM) > +#include > #define GEM_TRACE(...) trace_printk(__VA_ARGS__) > #define GEM_TRACE_ERR(...) do { \ > pr_err(__VA_ARGS__); \ > diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c > index c2e4b31b699a..d3f72dc430b8 100644 > --- a/drivers/tty/sysrq.c > +++ b/drivers/tty/sysrq.c > @@ -324,6 +324,7 @@ static const struct sysrq_key_op sysrq_showstate_blocked_op = { > }; > > #ifdef CONFIG_TRACING > +#include > #include > > static void sysrq_ftrace_dump(u8 key) > diff --git a/include/linux/trace_controls.h b/include/linux/trace_controls.h > new file mode 100644 > index 000000000000..995b97e963b4 > --- /dev/null > +++ b/include/linux/trace_controls.h > @@ -0,0 +1,54 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _LINUX_TRACE_CONTROLS_H > +#define _LINUX_TRACE_CONTROLS_H > + > + > +/* > + * General tracing related utility functions - trace_printk(), > + * tracing_on/tracing_off and tracing_start()/tracing_stop > + * > + * Use tracing_on/tracing_off when you want to quickly turn on or off > + * tracing. It simply enables or disables the recording of the trace events. > + * This also corresponds to the user space /sys/kernel/tracing/tracing_on > + * file, which gives a means for the kernel and userspace to interact. > + * Place a tracing_off() in the kernel where you want tracing to end. > + * From user space, examine the trace, and then echo 1 > tracing_on > + * to continue tracing. > + * > + * tracing_stop/tracing_start has slightly more overhead. It is used > + * by things like suspend to ram where disabling the recording of the > + * trace is not enough, but tracing must actually stop because things > + * like calling smp_processor_id() may crash the system. > + * > + * Most likely, you want to use tracing_on/tracing_off. > + */ > +enum ftrace_dump_mode { > + DUMP_NONE, > + DUMP_ALL, > + DUMP_ORIG, > + DUMP_PARAM, > +}; > + > +#ifdef CONFIG_TRACING > +void tracing_on(void); > +void tracing_off(void); > +int tracing_is_on(void); > +void tracing_snapshot(void); > +void tracing_snapshot_alloc(void); > +void tracing_start(void); > +void tracing_stop(void); > +void trace_dump_stack(int skip); The function description says: record a stack back trace in the trace buffer So, to me it sounds like it should go to the trace_printk.h. > +void ftrace_dump(enum ftrace_dump_mode oops_dump_mode); Same here, based on the function name, it relates to ftrace.h, not the tracing control itself. For example, lib/sys_info.c only calls ftrace_dump, and already includes ftrace.h. If you place ftrace_dump() as suggested, you can include only ftrace.h in there, and don't include trace_printk.h and trace_control.h Thanks, Yury > +#else > +static inline void tracing_start(void) { } > +static inline void tracing_stop(void) { } > +static inline void tracing_on(void) { } > +static inline void tracing_off(void) { } > +static inline int tracing_is_on(void) { return 0; } > +static inline void tracing_snapshot(void) { } > +static inline void tracing_snapshot_alloc(void) { } > +static inline void trace_dump_stack(int skip) { } > +static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } > +#endif > + > +#endif /* _LINUX_TRACE_CONTROLS_H */ > diff --git a/include/linux/trace_printk.h b/include/linux/trace_printk.h > index 3d54f440dccf..a488ea9e9f85 100644 > --- a/include/linux/trace_printk.h > +++ b/include/linux/trace_printk.h > @@ -7,43 +7,7 @@ > #include > #include > > -/* > - * General tracing related utility functions - trace_printk(), > - * tracing_on/tracing_off and tracing_start()/tracing_stop > - * > - * Use tracing_on/tracing_off when you want to quickly turn on or off > - * tracing. It simply enables or disables the recording of the trace events. > - * This also corresponds to the user space /sys/kernel/tracing/tracing_on > - * file, which gives a means for the kernel and userspace to interact. > - * Place a tracing_off() in the kernel where you want tracing to end. > - * From user space, examine the trace, and then echo 1 > tracing_on > - * to continue tracing. > - * > - * tracing_stop/tracing_start has slightly more overhead. It is used > - * by things like suspend to ram where disabling the recording of the > - * trace is not enough, but tracing must actually stop because things > - * like calling smp_processor_id() may crash the system. > - * > - * Most likely, you want to use tracing_on/tracing_off. > - */ > - > -enum ftrace_dump_mode { > - DUMP_NONE, > - DUMP_ALL, > - DUMP_ORIG, > - DUMP_PARAM, > -}; > - > #ifdef CONFIG_TRACING > -void tracing_on(void); > -void tracing_off(void); > -int tracing_is_on(void); > -void tracing_snapshot(void); > -void tracing_snapshot_alloc(void); > - > -extern void tracing_start(void); > -extern void tracing_stop(void); > - > static inline __printf(1, 2) > void ____trace_printk_check_format(const char *fmt, ...) > { > @@ -149,8 +113,6 @@ int __trace_printk(unsigned long ip, const char *fmt, ...); > extern int __trace_bputs(unsigned long ip, const char *str); > extern int __trace_puts(unsigned long ip, const char *str); > > -extern void trace_dump_stack(int skip); > - > /* > * The double __builtin_constant_p is because gcc will give us an error > * if we try to allocate the static variable to fmt if it is not a > @@ -173,19 +135,7 @@ __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap); > > extern __printf(2, 0) int > __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap); > - > -extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode); > #else > -static inline void tracing_start(void) { } > -static inline void tracing_stop(void) { } > -static inline void trace_dump_stack(int skip) { } > - > -static inline void tracing_on(void) { } > -static inline void tracing_off(void) { } > -static inline int tracing_is_on(void) { return 0; } > -static inline void tracing_snapshot(void) { } > -static inline void tracing_snapshot_alloc(void) { } > - > static inline __printf(1, 2) > int trace_printk(const char *fmt, ...) > { > @@ -196,7 +146,6 @@ ftrace_vprintk(const char *fmt, va_list ap) > { > return 0; > } > -static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } > #endif /* CONFIG_TRACING */ > > #endif > diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c > index b276504c1c6b..f9c83a470c98 100644 > --- a/kernel/debug/debug_core.c > +++ b/kernel/debug/debug_core.c > @@ -27,6 +27,7 @@ > > #define pr_fmt(fmt) "KGDB: " fmt > > +#include > #include > #include > #include > diff --git a/kernel/panic.c b/kernel/panic.c > index 213725b612aa..1415e910371d 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -9,6 +9,7 @@ > * This function is used through-out the kernel (including mm and fs) > * to indicate a major problem. > */ > +#include > #include > #include > #include > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h > index fa6d30ce73d1..b3e2c8f25a4f 100644 > --- a/kernel/rcu/rcu.h > +++ b/kernel/rcu/rcu.h > @@ -280,6 +280,8 @@ extern int rcu_cpu_stall_notifiers; > > #ifdef CONFIG_RCU_STALL_COMMON > > +#include > + > extern int rcu_cpu_stall_ftrace_dump; > extern int rcu_cpu_stall_suppress; > extern int rcu_cpu_stall_timeout; > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c > index 882a158ada7b..76bf0184b267 100644 > --- a/kernel/rcu/rcutorture.c > +++ b/kernel/rcu/rcutorture.c > @@ -39,6 +39,7 @@ > #include > #include > #include > +#include > #include > #include > #include > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index 80fe152af1dd..2537c33ddd49 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -22,6 +22,7 @@ > #include > #include > #include > +#include > #include > > #include "pid_list.h" > diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c > index e19c32f2a938..69cc39008c36 100644 > --- a/kernel/trace/trace_benchmark.c > +++ b/kernel/trace/trace_benchmark.c > @@ -3,6 +3,7 @@ > #include > #include > #include > +#include > > #define CREATE_TRACE_POINTS > #include "trace_benchmark.h" > diff --git a/lib/sys_info.c b/lib/sys_info.c > index f32a06ec9ed4..e3c9ca05601b 100644 > --- a/lib/sys_info.c > +++ b/lib/sys_info.c > @@ -8,6 +8,7 @@ > #include > #include > #include > +#include > #include > #include > > -- > 2.53.0 >