diff options
author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-12-12 17:46:45 -0300 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-12-16 13:38:26 -0300 |
commit | 8185e881f9fd9a2fa01f9d45616f8587f485f2a6 (patch) | |
tree | 70a7d5dd8ffd2f8b1a360468bcfb7c6cdaad4c0e /tools | |
parent | 38d5447d64f367d1f4804ed5c7048d39de4d3311 (diff) | |
download | linux-stable-8185e881f9fd9a2fa01f9d45616f8587f485f2a6.tar.gz linux-stable-8185e881f9fd9a2fa01f9d45616f8587f485f2a6.tar.bz2 linux-stable-8185e881f9fd9a2fa01f9d45616f8587f485f2a6.zip |
perf evlist: Do not use hard coded value for a mmap_pages default
So far what is in there by default is what we were using: 512KB + the
control page, but the admin may change that, and if it does to a smaller
value, all calls to tooling for non root users start failing, requiring
that the user manually set --mmap_pages/-m.
Use instead what is in /proc/sys/kernel/perf_event_mlock_kb.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-2f6mtm8xu3wo5lhkql6jdblh@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r-- | tools/perf/util/evlist.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 7847f3885081..ac808680e61c 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -893,10 +893,22 @@ out_unmap: static size_t perf_evlist__mmap_size(unsigned long pages) { - /* 512 kiB: default amount of unprivileged mlocked memory */ - if (pages == UINT_MAX) - pages = (512 * 1024) / page_size; - else if (!is_power_of_2(pages)) + if (pages == UINT_MAX) { + 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); + } + + pages = (max * 1024) / page_size; + } else if (!is_power_of_2(pages)) return 0; return (pages + 1) * page_size; |