perf kmem: Support field "node" in evsel__process_alloc_event() coping with recent tracepoint restructuring

Commit 11e9734bcb6a7361 ("mm/slab_common: unify NUMA and UMA version of
tracepoints") adds the field "node" into the tracepoints 'kmalloc' and
'kmem_cache_alloc', so this patch modifies the event process function to
support the field "node".

If field "node" is detected by checking function evsel__field(), it
stats the cross allocation.

When the "node" value is NUMA_NO_NODE (-1), it means the memory can be
allocated from any memory node, in this case, we don't account it as a
cross allocation.

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

···
 #include "util/string2.h"
 
 #include <linux/kernel.h>
+#include <linux/numa.h>
 #include <linux/rbtree.h>
 #include <linux/string.h>
 #include <linux/zalloc.h>
···
 	total_allocated += bytes_alloc;
 
 	nr_allocs++;
-	return 0;
-}
 
-static int evsel__process_alloc_node_event(struct evsel *evsel, struct perf_sample *sample)
-{
-	int ret = evsel__process_alloc_event(evsel, sample);
+	/*
+	 * Commit 11e9734bcb6a ("mm/slab_common: unify NUMA and UMA
+	 * version of tracepoints") adds the field "node" into the
+	 * tracepoints 'kmalloc' and 'kmem_cache_alloc'.
+	 *
+	 * The legacy tracepoints 'kmalloc_node' and 'kmem_cache_alloc_node'
+	 * also contain the field "node".
+	 *
+	 * If the tracepoint contains the field "node" the tool stats the
+	 * cross allocation.
+	 */
+	if (evsel__field(evsel, "node")) {
+		int node1, node2;
 
-	if (!ret) {
-		int node1 = cpu__get_node((struct perf_cpu){.cpu = sample->cpu}),
-		    node2 = evsel__intval(evsel, sample, "node");
+		node1 = cpu__get_node((struct perf_cpu){.cpu = sample->cpu});
+		node2 = evsel__intval(evsel, sample, "node");
 
-		if (node1 != node2)
+		/*
+		 * If the field "node" is NUMA_NO_NODE (-1), we don't take it
+		 * as a cross allocation.
+		 */
+		if ((node2 != NUMA_NO_NODE) && (node1 != node2))
 			nr_cross_allocs++;
 	}
 
-	return ret;
+	return 0;
 }
 
 static int ptr_cmp(void *, void *);
···
 		/* slab allocator */
 		{ "kmem:kmalloc",		evsel__process_alloc_event, },
 		{ "kmem:kmem_cache_alloc",	evsel__process_alloc_event, },
-		{ "kmem:kmalloc_node",		evsel__process_alloc_node_event, },
-		{ "kmem:kmem_cache_alloc_node", evsel__process_alloc_node_event, },
+		{ "kmem:kmalloc_node",		evsel__process_alloc_event, },
+		{ "kmem:kmem_cache_alloc_node", evsel__process_alloc_event, },
 		{ "kmem:kfree",			evsel__process_free_event, },
 		{ "kmem:kmem_cache_free",	evsel__process_free_event, },
 		/* page allocator */