The mmap/comm tracking code does quite a lot of work before it discovers there's no interest in it, avoid that by keeping a counter. Signed-off-by: Peter Zijlstra --- kernel/perf_counter.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) Index: linux-2.6/kernel/perf_counter.c =================================================================== --- linux-2.6.orig/kernel/perf_counter.c +++ linux-2.6/kernel/perf_counter.c @@ -38,6 +38,10 @@ int perf_max_counters __read_mostly = 1; static int perf_reserved_percpu __read_mostly; static int perf_overcommit __read_mostly = 1; +static atomic_t nr_mmap_tracking __read_mostly; +static atomic_t nr_munmap_tracking __read_mostly; +static atomic_t nr_comm_tracking __read_mostly; + /* * Mutex for (sysadmin-configurable) counter reservations: */ @@ -1186,6 +1190,13 @@ static void free_counter(struct perf_cou { perf_pending_sync(counter); + if (counter->hw_event.mmap) + atomic_dec(&nr_mmap_tracking); + if (counter->hw_event.munmap) + atomic_dec(&nr_munmap_tracking); + if (counter->hw_event.comm) + atomic_dec(&nr_comm_tracking); + if (counter->destroy) counter->destroy(counter); @@ -2128,7 +2139,12 @@ got_name: void perf_counter_mmap(unsigned long addr, unsigned long len, unsigned long pgoff, struct file *file) { - struct perf_mmap_event mmap_event = { + struct perf_mmap_event mmap_event; + + if (!atomic_read(&nr_mmap_tracking)) + return; + + mmap_event = (struct perf_mmap_event){ .file = file, .event = { .header = { .type = PERF_EVENT_MMAP, }, @@ -2146,7 +2162,12 @@ void perf_counter_mmap(unsigned long add void perf_counter_munmap(unsigned long addr, unsigned long len, unsigned long pgoff, struct file *file) { - struct perf_mmap_event mmap_event = { + struct perf_mmap_event mmap_event; + + if (!atomic_read(&nr_munmap_tracking)) + return; + + mmap_event = (struct perf_mmap_event){ .file = file, .event = { .header = { .type = PERF_EVENT_MUNMAP, }, @@ -2725,6 +2746,13 @@ done: counter->hw_ops = hw_ops; + if (counter->hw_event.mmap) + atomic_inc(&nr_mmap_tracking); + if (counter->hw_event.munmap) + atomic_inc(&nr_munmap_tracking); + if (counter->hw_event.comm) + atomic_inc(&nr_comm_tracking); + return counter; } -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/