perf evlist: Adopt the pollfd array

Allocating just the space needed for nr_cpus * nr_threads * nr_evsels,
not the MAX_NR_CPUS and counters.

LKML-Reference: <new-submission>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 7b4faec..2abf949 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1,3 +1,4 @@
+#include <poll.h>
 #include "evlist.h"
 #include "evsel.h"
 #include "util.h"
@@ -28,6 +29,7 @@
 void perf_evlist__delete(struct perf_evlist *evlist)
 {
 	perf_evlist__purge(evlist);
+	free(evlist->pollfd);
 	free(evlist);
 }
 
@@ -51,3 +53,10 @@
 	perf_evlist__add(evlist, evsel);
 	return 0;
 }
+
+int perf_evlist__alloc_pollfd(struct perf_evlist *evlist, int ncpus, int nthreads)
+{
+	int nfds = ncpus * nthreads * evlist->nr_entries;
+	evlist->pollfd = malloc(sizeof(struct pollfd) * nfds);
+	return evlist->pollfd != NULL ? 0 : -ENOMEM;
+}