perf tools: Add possibility to specify mmap size

Adding possibility to specify mmap size via -m/--mmap-pages
by appending unit size character (B/K/M/G) to the
number, like:
  $ perf record -m 8K ls
  $ perf record -m 2M ls

The size is rounded up appropriately to follow perf
mmap restrictions.

If no unit is specified the number provides pages as
of now, like:
  $ perf record -m 8 ls

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1378031796-17892-3-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index a535359..c29ecaa 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -270,6 +270,13 @@
 	return (n != 0 && ((n & (n - 1)) == 0));
 }
 
+static inline unsigned next_pow2(unsigned x)
+{
+	if (!x)
+		return 1;
+	return 1ULL << (32 - __builtin_clz(x - 1));
+}
+
 size_t hex_width(u64 v);
 int hex2u64(const char *ptr, u64 *val);
 
@@ -281,4 +288,11 @@
 extern unsigned int page_size;
 
 void get_term_dimensions(struct winsize *ws);
+
+struct parse_tag {
+	char tag;
+	int mult;
+};
+
+unsigned long parse_tag_value(const char *str, struct parse_tag *tags);
 #endif /* GIT_COMPAT_UTIL_H */