Hi Robert,
On Fri, 31 May 2013 11:16:25 +0200, Robert Richter wrote:
> From: Robert Richter <robert.rich...@calxeda.com>
>
> Persistent event buffers may only be mmapped readonly. Thus, retry
> mapping it readonly if mmap returns EACCES after trying to mmap
> writable.
>
> Signed-off-by: Robert Richter <robert.rich...@calxeda.com>
> ---
> tools/perf/builtin-record.c | 7 ++++++-
> tools/perf/builtin-top.c | 8 ++++++--
> tools/perf/perf.h | 1 +
> 3 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index cdf58ec..916776d 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -255,7 +255,12 @@ try_again:
> goto out;
> }
>
> - if (perf_evlist__mmap(evlist, opts->mmap_pages, false) < 0) {
> +try_again2:
> + if (perf_evlist__mmap(evlist, opts->mmap_pages, opts->mmap_ro) < 0) {
> + if (!opts->mmap_ro && errno == EACCES) {
> + opts->mmap_ro = true;
> + goto try_again2;
> + }
> if (errno == EPERM) {
> pr_err("Permission error mapping pages.\n"
> "Consider increasing "
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index 67bdb9f..2a5757d 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -899,8 +899,12 @@ try_again:
> goto out_err;
> }
> }
> -
> - if (perf_evlist__mmap(evlist, opts->mmap_pages, false) < 0) {
> +try_again2:
> + if (perf_evlist__mmap(evlist, opts->mmap_pages, opts->mmap_ro) < 0) {
> + if (!opts->mmap_ro && errno == EACCES) {
> + opts->mmap_ro = true;
> + goto try_again2;
> + }
> ui__error("Failed to mmap with %d (%s)\n",
> errno, strerror(errno));
> goto out_err;
You will need this also:
@@ -161,7 +161,8 @@ static int perf_record__mmap_read(struct perf_record *rec,
}
md->prev = old;
- perf_mmap__write_tail(md, old);
+ if (!rec->opts.mmap_ro)
+ perf_mmap__write_tail(md, old);
out:
return rc;
--
Thanks,
Namhyung
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