Reverse the delimiter logic so we only consume trace space and pollute the user output when the stack is incomplete.
Signed-off-by: Mathieu Desnoyers <[email protected]> --- lttng-context-callstack.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/lttng-context-callstack.c b/lttng-context-callstack.c index d95cbc2..6bfe794 100644 --- a/lttng-context-callstack.c +++ b/lttng-context-callstack.c @@ -159,10 +159,22 @@ size_t lttng_callstack_get_size(size_t offset, struct lttng_ctx_field *field, /* do the real work and reserve space */ cs_types[fdata->mode].save_func(trace); + /* + * Remove final ULONG_MAX delimiter. If we cannot find it, add + * our own marker to show that the stack is incomplete. This is + * more compact for a trace. + */ + if (trace->nr_entries > 0 + && trace->entries[trace->nr_entries - 1] == ULONG_MAX) { + trace->nr_entries--; + } size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int)); size += sizeof(unsigned int); size += lib_ring_buffer_align(offset, lttng_alignof(unsigned long)); size += sizeof(unsigned long) * trace->nr_entries; + /* Add our own ULONG_MAX delimiter to show incomplete stack. */ + if (trace->nr_entries == trace->max_entries) + size += sizeof(unsigned long); return size; } @@ -172,14 +184,24 @@ void lttng_callstack_record(struct lttng_ctx_field *field, struct lttng_channel *chan) { struct stack_trace *trace = stack_trace_context(field, ctx); + unsigned int nr_seq_entries; if (!trace) return; lib_ring_buffer_align_ctx(ctx, lttng_alignof(unsigned int)); - chan->ops->event_write(ctx, &trace->nr_entries, sizeof(unsigned int)); + nr_seq_entries = trace->nr_entries; + if (trace->nr_entries == trace->max_entries) + nr_seq_entries++; + chan->ops->event_write(ctx, &nr_seq_entries, sizeof(unsigned int)); lib_ring_buffer_align_ctx(ctx, lttng_alignof(unsigned long)); chan->ops->event_write(ctx, trace->entries, sizeof(unsigned long) * trace->nr_entries); + /* Add our own ULONG_MAX delimiter to show incomplete stack. */ + if (trace->nr_entries == trace->max_entries) { + unsigned long delim = ULONG_MAX; + + chan->ops->event_write(ctx, &delim, sizeof(unsigned long)); + } } static -- 2.1.4 _______________________________________________ lttng-dev mailing list [email protected] https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
