From d20e3b03842bfeb9d21817ff19054c277cc3eac0 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 2 Mar 2009 10:53:15 -0500 Subject: [PATCH] tracing: add TRACE_FIELD_SPECIAL to record complex entries Tom Zanussi pointed out that the simple TRACE_FIELD was not enough to record trace data that required memcpy. This patch addresses this issue by adding a TRACE_FIELD_SPECIAL. The format is similar to TRACE_FIELD but looks like so: TRACE_FIELD_SPECIAL(type_item, item, cmd) What TRACE_FIELD gave was: TRACE_FIELD(type, item, assign) The TRACE_FIELD would be used in declaring a structure: struct { type item; }; And later assign it via: entry->item = assign; What TRACE_FIELD_SPECIAL gives us is: In the declaration of the structure: struct { type_item; }; And the assignment: cmd; This change log will explain the one example used in the patch: TRACE_EVENT_FORMAT(sched_switch, TPPROTO(struct rq *rq, struct task_struct *prev, struct task_struct *next), TPARGS(rq, prev, next), TPFMT("task %s:%d ==> %s:%d", prev->comm, prev->pid, next->comm, next->pid), TRACE_STRUCT( TRACE_FIELD(pid_t, prev_pid, prev->pid) TRACE_FIELD(int, prev_prio, prev->prio) TRACE_FIELD_SPECIAL(char next_comm[TASK_COMM_LEN], next_comm, TPCMD(memcpy(TRACE_ENTRY->next_comm, next->comm, TASK_COMM_LEN))) TRACE_FIELD(pid_t, next_pid, next->pid) TRACE_FIELD(int, next_prio, next->prio) ), TPRAWFMT("prev %d:%d ==> next %s:%d:%d") ); The struct will be create as: struct { pid_t prev_pid; int prev_prio; char next_comm[TASK_COMM_LEN]; pid_t next_pid; int next_prio; }; Note the TRACE_ENTRY in the cmd part of TRACE_SPECIAL. TRACE_ENTRY will be set by the tracer to point to the structure inside the trace buffer. entry->prev_pid = prev->pid; entry->prev_prio = prev->prio; memcpy(entry->next_comm, next->comm, TASK_COMM_LEN); entry->next_pid = next->pid; entry->next_prio = next->prio Reported-by: Tom Zanussi Signed-off-by: Steven Rostedt --- include/trace/sched_event_types.h | 7 ++++++- kernel/trace/trace_events_stage_1.h | 2 ++ kernel/trace/trace_events_stage_2.h | 4 ++++ kernel/trace/trace_events_stage_3.h | 14 ++++++++++++++ 4 files changed, 26 insertions(+), 1 deletion(-) diff --git a/include/trace/sched_event_types.h b/include/trace/sched_event_types.h index ba059c10b58..a6de5c1601a 100644 --- a/include/trace/sched_event_types.h +++ b/include/trace/sched_event_types.h @@ -71,10 +71,15 @@ TRACE_EVENT_FORMAT(sched_switch, TRACE_STRUCT( TRACE_FIELD(pid_t, prev_pid, prev->pid) TRACE_FIELD(int, prev_prio, prev->prio) + TRACE_FIELD_SPECIAL(char next_comm[TASK_COMM_LEN], + next_comm, + TPCMD(memcpy(TRACE_ENTRY->next_comm, + next->comm, + TASK_COMM_LEN))) TRACE_FIELD(pid_t, next_pid, next->pid) TRACE_FIELD(int, next_prio, next->prio) ), - TPRAWFMT("prev %d:%d ==> next %d:%d") + TPRAWFMT("prev %d:%d ==> next %s:%d:%d") ); TRACE_EVENT_FORMAT(sched_migrate_task, diff --git a/kernel/trace/trace_events_stage_1.h b/kernel/trace/trace_events_stage_1.h index fd3bf9382d3..3830a731424 100644 --- a/kernel/trace/trace_events_stage_1.h +++ b/kernel/trace/trace_events_stage_1.h @@ -30,5 +30,7 @@ #define TRACE_FIELD(type, item, assign) \ type item; +#define TRACE_FIELD_SPECIAL(type_item, item, cmd) \ + type_item; #include diff --git a/kernel/trace/trace_events_stage_2.h b/kernel/trace/trace_events_stage_2.h index 3eaaef5f19e..dc79fe3a2ec 100644 --- a/kernel/trace/trace_events_stage_2.h +++ b/kernel/trace/trace_events_stage_2.h @@ -39,6 +39,10 @@ #define TRACE_FIELD(type, item, assign) \ field->item, +#undef TRACE_FIELD_SPECIAL +#define TRACE_FIELD_SPECIAL(type_item, item, cmd) \ + field->item, + #undef TPRAWFMT #define TPRAWFMT(args...) args diff --git a/kernel/trace/trace_events_stage_3.h b/kernel/trace/trace_events_stage_3.h index 7a161c49deb..2ab65e95822 100644 --- a/kernel/trace/trace_events_stage_3.h +++ b/kernel/trace/trace_events_stage_3.h @@ -147,6 +147,20 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ #define TRACE_FIELD(type, item, assign)\ entry->item = assign; +#undef TRACE_FIELD +#define TRACE_FIELD(type, item, assign)\ + entry->item = assign; + +#undef TPCMD +#define TPCMD(cmd...) cmd + +#undef TRACE_ENTRY +#define TRACE_ENTRY entry + +#undef TRACE_FIELD_SPECIAL +#define TRACE_FIELD_SPECIAL(type_item, item, cmd) \ + cmd; + #undef TRACE_EVENT_FORMAT #define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt) \ _TRACE_FORMAT(call, PARAMS(proto), PARAMS(args), PARAMS(fmt)) \ -- 2.41.1