Re: [PATCH 7/7] perf tools: Refine perf_mmap__read_init

[Liang, Kan]

On 3/5/2018 5:25 PM, Jiri Olsa wrote:

On Mon, Mar 05, 2018 at 02:10:59PM -0500, kan.li...@linux.intel.com wrote:

SNIP

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index e3921ed..403c5e6 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -235,16 +235,13 @@ static int overwrite_rb_find_range(void *buf, int mask, 
u64 head, u64 *start, u6
  /*
   * Report the start and end of the available data in ringbuffer
   */
-int perf_mmap__read_init(struct perf_mmap *md, bool overwrite,
-                        u64 *startp, u64 *endp)
+int perf_mmap__read_init(struct perf_mmap *md, bool overwrite)
  {
        u64 head = perf_mmap__read_head(md);
        u64 old = md->prev;
        unsigned char *data = md->base + page_size;
        unsigned long size;

- *startp = overwrite ? head : old;

-       *endp = overwrite ? old : head;
        md->overwrite = overwrite;

hum, can't we set 'overwrite' at the moment we create struct perf_mmap?

it's not changing during the mmap's lifetime.. maybe we could do it in
perf_evlist__alloc_mmap function

Yes, we know that the __alloc_mmap() is for mmap or overwrite_mmap.
I think we can set the 'overwrite' there.
I will do the change in V2.

Thanks,
Kan

really nice cleanup!

thanks,
jirka