From: Steven Rostedt The functions that assign the contents for the ftrace events are defined by the TRACE_EVENT() macros. Each event has its own unique way to assign data to its buffer. When you have over 500 events, that means there's 500 functions assigning data uniquely for each event (not really that many, as DECLARE_EVENT_CLASS() and multiple DEFINE_EVENT()s will only need a single function). By making helper functions in the core kernel to do some of the work instead, we can shrink the size of the kernel down a bit. With a kernel configured with 502 events, the change in size was: text data bss dec hex filename 12987390 1913504 9785344 24686238 178ae9e /tmp/vmlinux 12959102 1913504 9785344 24657950 178401e /tmp/vmlinux.patched That's a total of 28288 bytes, which comes down to 56 bytes per event. Link: http://lkml.kernel.org/r/20120810034708.370808175@goodmis.org Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 16 ++++++++++++++++ include/trace/ftrace.h | 20 ++++++-------------- kernel/trace/trace_output.c | 31 +++++++++++++++++++++++++++++++ 3 files changed, 53 insertions(+), 14 deletions(-) diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 014090c..4cc6852 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -205,6 +205,22 @@ int ftrace_event_define_field(struct ftrace_event_call *call, char *type, int len, char *item, int offset, int field_size, int sign, int filter); +struct ftrace_event_buffer { + struct ring_buffer *buffer; + struct ring_buffer_event *event; + struct ftrace_event_file *ftrace_file; + void *entry; + unsigned long flags; + int pc; +}; + +void *ftrace_event_buffer_reserve(struct ftrace_event_buffer *fbuffer, + struct ftrace_event_file *ftrace_file, + int type, unsigned long len); + +void ftrace_event_buffer_commit(struct ftrace_event_buffer *fbuffer, + struct ftrace_event_call *event_call); + enum { TRACE_EVENT_FL_FILTERED_BIT, TRACE_EVENT_FL_CAP_ANY_BIT, diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index c9c991f..dc883a3 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -520,36 +520,28 @@ ftrace_raw_event_##call(void *__data, proto) \ struct ftrace_event_file *ftrace_file = __data; \ struct ftrace_event_call *event_call = ftrace_file->event_call; \ struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\ - struct ring_buffer_event *event; \ + struct ftrace_event_buffer fbuffer; \ struct ftrace_raw_##call *entry; \ - struct ring_buffer *buffer; \ - unsigned long irq_flags; \ int __data_size; \ - int pc; \ \ if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, \ &ftrace_file->flags)) \ return; \ \ - local_save_flags(irq_flags); \ - pc = preempt_count(); \ - \ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ \ - event = trace_event_buffer_lock_reserve(&buffer, ftrace_file, \ + entry = ftrace_event_buffer_reserve(&fbuffer, ftrace_file, \ event_call->event.type, \ - sizeof(*entry) + __data_size, \ - irq_flags, pc); \ - if (!event) \ + sizeof(*entry) + __data_size); \ + \ + if (!entry) \ return; \ - entry = ring_buffer_event_data(event); \ \ tstruct \ \ { assign; } \ \ - if (!filter_check_discard(ftrace_file, entry, buffer, event)) \ - trace_buffer_unlock_commit(buffer, event, irq_flags, pc); \ + ftrace_event_buffer_commit(&fbuffer, event_call); \ } /* * The ftrace_test_probe is compiled out, it is only here as a build time check diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index ee8d748..fae6c9b 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -491,6 +491,37 @@ int ftrace_event_define_field(struct ftrace_event_call *call, } EXPORT_SYMBOL_GPL(ftrace_event_define_field); +void *ftrace_event_buffer_reserve(struct ftrace_event_buffer *fbuffer, + struct ftrace_event_file *ftrace_file, + int type, unsigned long len) +{ + local_save_flags(fbuffer->flags); + fbuffer->pc = preempt_count(); + fbuffer->ftrace_file = ftrace_file; + + fbuffer->event = + trace_event_buffer_lock_reserve(&fbuffer->buffer, ftrace_file, + type, len, + fbuffer->flags, fbuffer->pc); + if (!fbuffer->event) + return NULL; + + fbuffer->entry = ring_buffer_event_data(fbuffer->event); + return fbuffer->entry; +} +EXPORT_SYMBOL_GPL(ftrace_event_buffer_reserve); + +void ftrace_event_buffer_commit(struct ftrace_event_buffer *fbuffer, + struct ftrace_event_call *event_call) +{ + if (!filter_check_discard(fbuffer->ftrace_file, fbuffer->entry, + fbuffer->buffer, fbuffer->event)) + trace_buffer_unlock_commit(fbuffer->buffer, + fbuffer->event, + fbuffer->flags, fbuffer->pc); +} +EXPORT_SYMBOL_GPL(ftrace_event_buffer_commit); + #ifdef CONFIG_KRETPROBES static inline const char *kretprobed(const char *name) { -- 1.8.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/