Commit-ID: 8185e881f9fd9a2fa01f9d45616f8587f485f2a6 Gitweb: http://git.kernel.org/tip/8185e881f9fd9a2fa01f9d45616f8587f485f2a6 Author: Arnaldo Carvalho de Melo <[email protected]> AuthorDate: Fri, 12 Dec 2014 17:46:45 -0300 Committer: Arnaldo Carvalho de Melo <[email protected]> CommitDate: Tue, 16 Dec 2014 13:38:26 -0300
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 <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: David Ahern <[email protected]> Cc: Don Zickus <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephane Eranian <[email protected]> Link: http://lkml.kernel.org/n/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- tools/perf/util/evlist.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 7847f38..ac80868 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
