perf kmem: Support legacy tracepoints

Commit 11e9734bcb6a7361 ("mm/slab_common: unify NUMA and UMA version of
tracepoints") removed tracepoints 'kmalloc_node' and
'kmem_cache_alloc_node', we need to consider the tool should be backward
compatible.

If it detect the tracepoint "kmem:kmalloc_node", this patch enables the
legacy tracepoints, otherwise, it will ignore them.

Fixes: 11e9734bcb6a7361 ("mm/slab_common: unify NUMA and UMA version of tracepoints")
Reported-by: Ravi Bangoria <[e-mail]>
Reviewed-by: James Clark <[e-mail]>
Signed-off-by: Leo Yan <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Hyeonggon Yoo <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-kmem.c

···
 	return 0;
 }
 
+static bool slab_legacy_tp_is_exposed(void)
+{
+	/*
+	 * The tracepoints "kmem:kmalloc_node" and
+	 * "kmem:kmem_cache_alloc_node" have been removed on the latest
+	 * kernel, if the tracepoint "kmem:kmalloc_node" is existed it
+	 * means the tool is running on an old kernel, we need to
+	 * rollback to support these legacy tracepoints.
+	 */
+	return IS_ERR(trace_event__tp_format("kmem", "kmalloc_node")) ?
+		false : true;
+}
+
 static int __cmd_record(int argc, const char **argv)
 {
 	const char * const record_args[] = {
···
 	};
 	const char * const slab_events[] = {
 	"-e", "kmem:kmalloc",
-	"-e", "kmem:kmalloc_node",
 	"-e", "kmem:kfree",
 	"-e", "kmem:kmem_cache_alloc",
-	"-e", "kmem:kmem_cache_alloc_node",
 	"-e", "kmem:kmem_cache_free",
+	};
+	const char * const slab_legacy_events[] = {
+	"-e", "kmem:kmalloc_node",
+	"-e", "kmem:kmem_cache_alloc_node",
 	};
 	const char * const page_events[] = {
 	"-e", "kmem:mm_page_alloc",
···
 	};
 	unsigned int rec_argc, i, j;
 	const char **rec_argv;
+	unsigned int slab_legacy_tp_exposed = slab_legacy_tp_is_exposed();
 
 	rec_argc = ARRAY_SIZE(record_args) + argc - 1;
-	if (kmem_slab)
+	if (kmem_slab) {
 		rec_argc += ARRAY_SIZE(slab_events);
+		if (slab_legacy_tp_exposed)
+			rec_argc += ARRAY_SIZE(slab_legacy_events);
+	}
 	if (kmem_page)
 		rec_argc += ARRAY_SIZE(page_events) + 1; /* for -g */
 
···
 	if (kmem_slab) {
 		for (j = 0; j < ARRAY_SIZE(slab_events); j++, i++)
 			rec_argv[i] = strdup(slab_events[j]);
+		if (slab_legacy_tp_exposed) {
+			for (j = 0; j < ARRAY_SIZE(slab_legacy_events); j++, i++)
+				rec_argv[i] = strdup(slab_legacy_events[j]);
+		}
 	}
 	if (kmem_page) {
 		rec_argv[i++] = strdup("-g");