perf evsel: Cache associated event_format

We already lookup the associated event_format when reading the perf.data
header, so that we can cache the tracepoint name in evsel->name, so do
it a little further and save the event_format itself, so that we can
avoid relookups in tools that need to access it.

Change the tools to take the most obvious advantage, when they were
using pevent_find_event directly. More work is needed for further
removing the need of a pointer to pevent, such as when asking for event
field values ("common_pid" and the other common fields and per
event_format fields).

This is something that was planned but only got actually done when
Andrey Wagin needed to do this lookup at perf_tool->sample() time, when
we don't have access to pevent (session->pevent) to use with
pevent_find_event().

Cc: Andrey Wagin <avagin@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/n/tip-txkvew2ckko0b594ae8fbnyk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-kmem.c b/tools/perf/builtin-kmem.c
index ce35015..ffb93f42 100644
--- a/tools/perf/builtin-kmem.c
+++ b/tools/perf/builtin-kmem.c
@@ -1,6 +1,7 @@
 #include "builtin.h"
 #include "perf.h"
 
+#include "util/evsel.h"
 #include "util/util.h"
 #include "util/cache.h"
 #include "util/symbol.h"
@@ -57,11 +58,6 @@
 
 #define PATH_SYS_NODE	"/sys/devices/system/node"
 
-struct perf_kmem {
-	struct perf_tool    tool;
-	struct perf_session *session;
-};
-
 static void init_cpunode_map(void)
 {
 	FILE *fp;
@@ -283,16 +279,10 @@
 	s_alloc->alloc_cpu = -1;
 }
 
-static void process_raw_event(struct perf_tool *tool,
-			      union perf_event *raw_event __used, void *data,
+static void process_raw_event(struct perf_evsel *evsel, void *data,
 			      int cpu, u64 timestamp, struct thread *thread)
 {
-	struct perf_kmem *kmem = container_of(tool, struct perf_kmem, tool);
-	struct event_format *event;
-	int type;
-
-	type = trace_parse_common_type(kmem->session->pevent, data);
-	event = pevent_find_event(kmem->session->pevent, type);
+	struct event_format *event = evsel->tp_format;
 
 	if (!strcmp(event->name, "kmalloc") ||
 	    !strcmp(event->name, "kmem_cache_alloc")) {
@@ -313,10 +303,10 @@
 	}
 }
 
-static int process_sample_event(struct perf_tool *tool,
+static int process_sample_event(struct perf_tool *tool __used,
 				union perf_event *event,
 				struct perf_sample *sample,
-				struct perf_evsel *evsel __used,
+				struct perf_evsel *evsel,
 				struct machine *machine)
 {
 	struct thread *thread = machine__findnew_thread(machine, event->ip.pid);
@@ -329,18 +319,16 @@
 
 	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
 
-	process_raw_event(tool, event, sample->raw_data, sample->cpu,
+	process_raw_event(evsel, sample->raw_data, sample->cpu,
 			  sample->time, thread);
 
 	return 0;
 }
 
-static struct perf_kmem perf_kmem = {
-	.tool = {
-		.sample			= process_sample_event,
-		.comm			= perf_event__process_comm,
-		.ordered_samples	= true,
-	},
+static struct perf_tool perf_kmem = {
+	.sample		 = process_sample_event,
+	.comm		 = perf_event__process_comm,
+	.ordered_samples = true,
 };
 
 static double fragmentation(unsigned long n_req, unsigned long n_alloc)
@@ -497,13 +485,10 @@
 	int err = -EINVAL;
 	struct perf_session *session;
 
-	session = perf_session__new(input_name, O_RDONLY, 0, false,
-				    &perf_kmem.tool);
+	session = perf_session__new(input_name, O_RDONLY, 0, false, &perf_kmem);
 	if (session == NULL)
 		return -ENOMEM;
 
-	perf_kmem.session = session;
-
 	if (perf_session__create_kernel_maps(session) < 0)
 		goto out_delete;
 
@@ -511,7 +496,7 @@
 		goto out_delete;
 
 	setup_pager();
-	err = perf_session__process_events(session, &perf_kmem.tool);
+	err = perf_session__process_events(session, &perf_kmem);
 	if (err != 0)
 		goto out_delete;
 	sort_result();