the size of seq field in trace_iterator is more than PAGE_SIZE, so seq memset is expensive, try to use cheap seq init method: trace_seq_init
Signed-off-by: zhangwei(Jovi) <[email protected]> --- kernel/trace/trace.c | 10 ++++++---- kernel/trace/trace_kdb.c | 5 +++-- 2 files changed, 9 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4cec7b8..c7cc915 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3551,9 +3551,10 @@ waitagain: cnt = PAGE_SIZE - 1; /* reset all but tr, trace, and overruns */ - memset(&iter->seq, 0, + trace_seq_init(&iter->seq); + memset(&iter->ent, 0, sizeof(struct trace_iterator) - - offsetof(struct trace_iterator, seq)); + offsetof(struct trace_iterator, ent)); iter->pos = -1; trace_event_read_lock(); @@ -5167,9 +5168,10 @@ __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode) cnt++; /* reset all but tr, trace, and overruns */ - memset(&iter.seq, 0, + trace_seq_init(&iter.seq); + memset(&iter.ent, 0, sizeof(struct trace_iterator) - - offsetof(struct trace_iterator, seq)); + offsetof(struct trace_iterator, ent)); iter.iter_flags |= TRACE_FILE_LAT_FMT; iter.pos = -1; diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c index 6489b2e..84f1584 100644 --- a/kernel/trace/trace_kdb.c +++ b/kernel/trace/trace_kdb.c @@ -37,9 +37,10 @@ static void ftrace_dump_buf(int skip_lines, long cpu_file) kdb_printf("Dumping ftrace buffer:\n"); /* reset all but tr, trace, and overruns */ - memset(&iter.seq, 0, + trace_seq_init(&iter.seq); + memset(&iter.ent, 0, sizeof(struct trace_iterator) - - offsetof(struct trace_iterator, seq)); + offsetof(struct trace_iterator, ent)); iter.iter_flags |= TRACE_FILE_LAT_FMT; iter.pos = -1; -- 1.7.9.7 -- 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/
