From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Shrink the struct tracepoint size from 80 bytes to 72 bytes on x86-64 by moving the (typically NULL) regfunc/unregfunc pointers to an extended structure. Tested-by: Jordan Rife <jrife@xxxxxxxxxx> Cc: Michael Jeanson <mjeanson@xxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Yonghong Song <yhs@xxxxxx> Cc: Paul E. McKenney <paulmck@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> Cc: Namhyung Kim <namhyung@xxxxxxxxxx> Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> Cc: bpf@xxxxxxxxxxxxxxx Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> Cc: Jordan Rife <jrife@xxxxxxxxxx> Cc: linux-trace-kernel@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/20241031152056.744137-2-mathieu.desnoyers@xxxxxxxxxxxx Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> --- include/linux/tracepoint-defs.h | 8 ++++++-- include/linux/tracepoint.h | 19 +++++++++++++------ kernel/tracepoint.c | 9 ++++----- 3 files changed, 23 insertions(+), 13 deletions(-) diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h index 60a6e8314d4c..967c08d9da84 100644 --- a/include/linux/tracepoint-defs.h +++ b/include/linux/tracepoint-defs.h @@ -29,6 +29,11 @@ struct tracepoint_func { int prio; }; +struct tracepoint_ext { + int (*regfunc)(void); + void (*unregfunc)(void); +}; + struct tracepoint { const char *name; /* Tracepoint name */ struct static_key_false key; @@ -36,9 +41,8 @@ struct tracepoint { void *static_call_tramp; void *iterator; void *probestub; - int (*regfunc)(void); - void (*unregfunc)(void); struct tracepoint_func __rcu *funcs; + struct tracepoint_ext *ext; }; #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 0dc67fad706c..862ab49177a4 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -302,7 +302,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) * structures, so we create an array of pointers that will be used for iteration * on the tracepoints. */ -#define DEFINE_TRACE_FN(_name, _reg, _unreg, proto, args) \ +#define __DEFINE_TRACE_EXT(_name, _ext, proto, args) \ static const char __tpstrtab_##_name[] \ __section("__tracepoints_strings") = #_name; \ extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name); \ @@ -316,9 +316,9 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) .static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \ .iterator = &__traceiter_##_name, \ .probestub = &__probestub_##_name, \ - .regfunc = _reg, \ - .unregfunc = _unreg, \ - .funcs = NULL }; \ + .funcs = NULL, \ + .ext = _ext, \ + }; \ __TRACEPOINT_ENTRY(_name); \ int __traceiter_##_name(void *__data, proto) \ { \ @@ -341,8 +341,15 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) } \ DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); -#define DEFINE_TRACE(name, proto, args) \ - DEFINE_TRACE_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args)); +#define DEFINE_TRACE_FN(_name, _reg, _unreg, _proto, _args) \ + static struct tracepoint_ext __tracepoint_ext_##_name = { \ + .regfunc = _reg, \ + .unregfunc = _unreg, \ + }; \ + __DEFINE_TRACE_EXT(_name, &__tracepoint_ext_##_name, PARAMS(_proto), PARAMS(_args)); + +#define DEFINE_TRACE(_name, _proto, _args) \ + __DEFINE_TRACE_EXT(_name, NULL, PARAMS(_proto), PARAMS(_args)); #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \ EXPORT_SYMBOL_GPL(__tracepoint_##name); \ diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 6474e2cf22c9..5658dc92f5b5 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -278,8 +278,8 @@ static int tracepoint_add_func(struct tracepoint *tp, struct tracepoint_func *old, *tp_funcs; int ret; - if (tp->regfunc && !static_key_enabled(&tp->key)) { - ret = tp->regfunc(); + if (tp->ext && tp->ext->regfunc && !static_key_enabled(&tp->key)) { + ret = tp->ext->regfunc(); if (ret < 0) return ret; } @@ -362,9 +362,8 @@ static int tracepoint_remove_func(struct tracepoint *tp, switch (nr_func_state(tp_funcs)) { case TP_FUNC_0: /* 1->0 */ /* Removed last function */ - if (tp->unregfunc && static_key_enabled(&tp->key)) - tp->unregfunc(); - + if (tp->ext && tp->ext->unregfunc && static_key_enabled(&tp->key)) + tp->ext->unregfunc(); static_branch_disable(&tp->key); /* Set iterator static call */ tracepoint_update_call(tp, tp_funcs); -- 2.45.2
