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author | Steven Rostedt <srostedt@redhat.com> | 2009-03-02 10:53:15 -0500 |
---|---|---|
committer | Steven Rostedt <srostedt@redhat.com> | 2009-03-02 10:53:15 -0500 |
commit | d20e3b03842bfeb9d21817ff19054c277cc3eac0 (patch) | |
tree | 5de7ef8a95f9391a264df358336842c9301f3868 | |
parent | f2034f1e1adaac6713a6d48b5a2d4f3aa3e63ccb (diff) | |
download | op-kernel-dev-d20e3b03842bfeb9d21817ff19054c277cc3eac0.zip op-kernel-dev-d20e3b03842bfeb9d21817ff19054c277cc3eac0.tar.gz |
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 <tzanussi@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
-rw-r--r-- | include/trace/sched_event_types.h | 7 | ||||
-rw-r--r-- | kernel/trace/trace_events_stage_1.h | 2 | ||||
-rw-r--r-- | kernel/trace/trace_events_stage_2.h | 4 | ||||
-rw-r--r-- | kernel/trace/trace_events_stage_3.h | 14 |
4 files changed, 26 insertions, 1 deletions
diff --git a/include/trace/sched_event_types.h b/include/trace/sched_event_types.h index ba059c1..a6de5c1 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 fd3bf93..3830a73 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 <trace/trace_event_types.h> diff --git a/kernel/trace/trace_events_stage_2.h b/kernel/trace/trace_events_stage_2.h index 3eaaef5..dc79fe3 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 7a161c4..2ab65e9 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)) \ |