Messages in this thread | | | Subject | Re: [PATCH 1/2 v2] tracing/events: provide string with undefined size support | From | Peter Zijlstra <> | Date | Fri, 17 Apr 2009 12:39:34 +0200 |
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On Fri, 2009-04-17 at 06:10 -0400, Steven Rostedt wrote:
> When I replied to Frederic, I thought I could come up with a way to do > something like you are proposing. Instead, I only ended up with the > variant that Frederic implemented. > > I've done what you are suggesting several times in tracing. Logdev does > this in its tracing. > > The problem that we have, is that we don't have actual code. We have a > TRACE_EVENT macro that is doing the work for us. This, unfortunately, > limits what we can do.
Can't you do things like:
#define __string(x) unsigned long length_##x, offset_##x;
TP_STRUCT__entry
size = sizeof(struct foo);
#define __string(x) length_##x = strlen(x) + 1; size += length_##x;
TP_STRUCT__entry
entry = ring_buffer_lock_reserve(size); offset = sizeof(stuct foo);
#define __string(x) \ __entry->x = offset_##x = offset; offset += length_##x;
TP_STRUCT__entry
TP_fast_assign
#define _string(x) strcpy(&entry->data[offset_##x], x);
TP_STRUCT__entry
ring_buffer_unlock();
also, you don't need that __ending_string() thing, you can always end a struct with char data[0], its 0 size ;-)
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