Commit-ID: f5e7150cd9a7779a54b192d21afb9245384db8bc
Gitweb: http://git.kernel.org/tip/f5e7150cd9a7779a54b192d21afb9245384db8bc
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Fri, 15 Apr 2016 17:46:31 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 15 Apr 2016 17:46:31 -0300
perf evlist: Expose perf_event_mlock_kb_in_pages() helper
When the user doesn't set --mmap-pages, perf_evlist__mmap() will do it
by reading the maximum possible for a non-root user from the
/proc/sys/kernel/perf_event_mlock_kb file.
Expose that function so that 'perf trace' can, for root users, to bump
mmap-pages to a higher value for root, based on the contents of this
proc file.
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Milian Wolff <milian.wolff@xxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-xay69plylwibpb3l4isrpl1k@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/evlist.c | 42 +++++++++++++++++++++++++-----------------
tools/perf/util/evlist.h | 2 ++
2 files changed, 27 insertions(+), 17 deletions(-)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 4c9f510..6fb5725 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -986,26 +986,34 @@ out_unmap:
return -1;
}
-static size_t perf_evlist__mmap_size(unsigned long pages)
+unsigned long perf_event_mlock_kb_in_pages(void)
{
- if (pages == UINT_MAX) {
- int max;
+ unsigned long pages;
+ int max;
- if (sysctl__read_int("kernel/perf_event_mlock_kb", &max) < 0) {
- /*
- * Pick a once upon a time good value, i.e. things look
- * strange since we can't read a sysctl value, but lets not
- * die yet...
- */
- max = 512;
- } else {
- max -= (page_size / 1024);
- }
+ if (sysctl__read_int("kernel/perf_event_mlock_kb", &max) < 0) {
+ /*
+ * Pick a once upon a time good value, i.e. things look
+ * strange since we can't read a sysctl value, but lets not
+ * die yet...
+ */
+ max = 512;
+ } else {
+ max -= (page_size / 1024);
+ }
+
+ pages = (max * 1024) / page_size;
+ if (!is_power_of_2(pages))
+ pages = rounddown_pow_of_two(pages);
- pages = (max * 1024) / page_size;
- if (!is_power_of_2(pages))
- pages = rounddown_pow_of_two(pages);
- } else if (!is_power_of_2(pages))
+ return pages;
+}
+
+static size_t perf_evlist__mmap_size(unsigned long pages)
+{
+ if (pages == UINT_MAX)
+ pages = perf_event_mlock_kb_in_pages();
+ else if (!is_power_of_2(pages))
return 0;
return (pages + 1) * page_size;
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index da46423..208897a 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -158,6 +158,8 @@ int perf_evlist__parse_mmap_pages(const struct option *opt,
const char *str,
int unset);
+unsigned long perf_event_mlock_kb_in_pages(void);
+
int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
bool overwrite, unsigned int auxtrace_pages,
bool auxtrace_overwrite);
--
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