[PATCH v3 2/3] perf mmap: declare type for cpu mask of arbitrary length

[Alexey Budankov]

Declare a dedicated struct map_cpu_mask type for cpu masks of
arbitrary length. Mask is available thru bits pointer and the
mask length is kept in nbits field. MMAP_CPU_MASK_BYTES() macro
returns mask storage size in bytes. perf_mmap__print_cpu_mask()
function can be used to log text representation of the mask.

Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
---
Changes in v3:
- implemented perf_mmap__print_cpu_mask() function
Changes in v2:
- capitalized MMAP_CPU_MASK_BYTES() macro
---
 tools/perf/util/mmap.c | 12 ++++++++++++
 tools/perf/util/mmap.h | 11 +++++++++++
 2 files changed, 23 insertions(+)

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index 063d1b93c53d..30ff7aef06f2 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -23,6 +23,18 @@
 #include "mmap.h"
 #include "../perf.h"
 #include <internal/lib.h> /* page_size */
+#include <linux/bitmap.h>
+
+#define MASK_SIZE 1023
+void perf_mmap__print_cpu_mask(struct mmap_cpu_mask *mask, const char *tag)
+{
+	char buf[MASK_SIZE + 1];
+	size_t len;
+
+	len = bitmap_scnprintf(mask->bits, mask->nbits, buf, MASK_SIZE);
+	buf[len] = '\0';
+	pr_debug("%p: %s mask[%ld]: %s\n", mask, tag, mask->nbits, buf);
+}
 
 size_t mmap__mmap_len(struct mmap *map)
 {
diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index bee4e83f7109..598e2def8a48 100644
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -15,6 +15,15 @@
 #include "event.h"
 
 struct aiocb;
+
+struct mmap_cpu_mask {
+	unsigned long *bits;
+	size_t nbits;
+};
+
+#define MMAP_CPU_MASK_BYTES(m) \
+	(BITS_TO_LONGS(((struct mmap_cpu_mask *)m)->nbits) * sizeof(unsigned long))
+
 /**
  * struct mmap - perf's ring buffer mmap details
  *
@@ -52,4 +61,6 @@ int perf_mmap__push(struct mmap *md, void *to,
 
 size_t mmap__mmap_len(struct mmap *map);
 
+void perf_mmap__print_cpu_mask(struct mmap_cpu_mask *mask, const char *tag);
+
 #endif /*__PERF_MMAP_H */
-- 
2.20.1