Hi Miloody
I found there seems no declaring about "struct ftrace_entry". below the greping result of my kernel source code:
# grep -rwn 'struct ftrace_entry' * kernel/trace/trace.h:214: IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN); \ kernel/trace/trace_events.c:1483: struct ftrace_entry *entry; kernel/trace/trace_output.c:818: struct ftrace_entry *field; kernel/trace/trace_output.c:845: struct ftrace_entry *field; kernel/trace/trace_output.c:859: struct ftrace_entry *field; kernel/trace/trace_output.c:872: struct ftrace_entry *field; kernel/trace/trace.c:1098: struct ftrace_entry *entry;
usually we use a struct we will declare its elements such as:
struct usb_host_endpoint { struct usb_endpoint_descriptor desc; struct list_head urb_list; void *hcpriv; ...................... };
I think this struct is not explicitly declared but generated by a macro. Look in kernel/trace/trace_entries.h The code that uses struct ftrace_entry all seems to #include this file either directly or indirectly: Directly by kernel/trace/trace_export.c and kernel/trace/trace.h Then kernel/trace/trace.c includes trace.h kernel/trace/trace_output.h includes trace.h kernel/trace/trace_output.c and kernel/trace/trace_events.c include trace_output.h I don't know why there is an advantage to creating a struct this way (perhaps a performance/storage advantage?) but then I haven't looked at the code in a lot of detail. Cheers Julie