diff options
author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-04-15 17:46:31 -0300 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-04-15 17:46:31 -0300 |
commit | f5e7150cd9a7779a54b192d21afb9245384db8bc (patch) | |
tree | e061fe5d0e029765c5c4e57d68cc503198f66bba | |
parent | 056149932602ef905f1e26fc4fe242ef0533a597 (diff) |
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@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-xay69plylwibpb3l4isrpl1k@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r-- | tools/perf/util/evlist.c | 42 | ||||
-rw-r--r-- | 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 4c9f510ae18d..6fb5725821de 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 da46423998e8..208897a646ca 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); |