tracing/perf: Move the PERF_MAX_TRACE_SIZE check into perf_trace_buf_prepare()

Every perf_trace_buf_prepare() caller does
WARN_ONCE(size > PERF_MAX_TRACE_SIZE, message) and "message" is
almost the same.

Shift this WARN_ONCE() into perf_trace_buf_prepare(). This changes
the meaning of _ONCE, but I think this is fine.

	- 4947014 2932448 10104832  17984294  1126b26 vmlinux
	+ 4948422 2932448 10104832  17985702  11270a6 vmlinux

on my build.

Link: http://lkml.kernel.org/r/20130617170211.GA19813@redhat.com
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index d615f78..41a6643 100644 (file)
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -670,10 +670,6 @@ perf_trace_##call(void *__data, proto)                                     \
                             sizeof(u64));                              \
        __entry_size -= sizeof(u32);                                    \
                                                                        \
-       if (WARN_ONCE(__entry_size > PERF_MAX_TRACE_SIZE,               \
-                     "profile buffer not large enough"))               \
-               return;                                                 \
-                                                                       \
        entry = (struct ftrace_raw_##call *)perf_trace_buf_prepare(     \
                __entry_size, event_call->event.type, &__regs, &rctx);  \
        if (!entry)                                                     \

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 12df557..80c36bc 100644 (file)
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -236,6 +236,10 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
 
        BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
 
+       if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
+                       "perf buffer not large enough"))
+               return NULL;
+
        pc = preempt_count();
 
        *rctxp = perf_swevent_get_recursion_context();

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 7ed6976..ae6ce83 100644 (file)
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1087,9 +1087,6 @@ kprobe_perf_func(struct trace_probe *tp, struct pt_regs *regs)
        __size = sizeof(*entry) + tp->size + dsize;
        size = ALIGN(__size + sizeof(u32), sizeof(u64));
        size -= sizeof(u32);
-       if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-                    "profile buffer not large enough"))
-               return;
 
        entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
        if (!entry)
@@ -1120,9 +1117,6 @@ kretprobe_perf_func(struct trace_probe *tp, struct kretprobe_instance *ri,
        __size = sizeof(*entry) + tp->size + dsize;
        size = ALIGN(__size + sizeof(u32), sizeof(u64));
        size -= sizeof(u32);
-       if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-                    "profile buffer not large enough"))
-               return;
 
        entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
        if (!entry)

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index ac00857..8fd0365 100644 (file)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -575,10 +575,6 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
        size = ALIGN(size + sizeof(u32), sizeof(u64));
        size -= sizeof(u32);
 
-       if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-                     "perf buffer not large enough"))
-               return;
-
        rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
                                sys_data->enter_event->event.type, regs, &rctx);
        if (!rec)
@@ -652,14 +648,6 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
        size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
        size -= sizeof(u32);
 
-       /*
-        * Impossible, but be paranoid with the future
-        * How to put this check outside runtime?
-        */
-       if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-               "exit event has grown above perf buffer size"))
-               return;
-
        rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
                                sys_data->exit_event->event.type, regs, &rctx);
        if (!rec)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index d5d0cd3..a23d2d7 100644 (file)
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -818,8 +818,6 @@ static void uprobe_perf_print(struct trace_uprobe *tu,
 
        size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
        size = ALIGN(size + tu->size + sizeof(u32), sizeof(u64)) - sizeof(u32);
-       if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
-               return;
 
        preempt_disable();
        head = this_cpu_ptr(call->perf_events);