Messages in this thread | | | Date | Mon, 14 Jul 2014 08:21:17 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] ftrace: Do not copy old hash when resetting. |
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On Mon, 14 Jul 2014 12:10:00 +0800 Wang Nan <wangnan0@huawei.com> wrote:
> If we are going to reset hash, we don't need to duplicate old hash > and remove every entries right after allocation. > > Signed-off-by: Wang Nan <wangnan0@huawei.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Ingo Molnar <mingo@redhat.com> > --- > kernel/trace/ftrace.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index 5b372e3..52d6931 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -3471,14 +3471,16 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len, > else > orig_hash = &ops->notrace_hash; > > - hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); > + if (!reset) > + hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); > + else > + hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
I'm fine with this patch, but please swap the if statement above. I prefer the if condition being positive if there's also an else statement above. That is:
if (reset) hash = alloc_ftrace_hash(); else hash = alloc_and_copy_ftrace_hash();
-- Steve
> + > if (!hash) { > ret = -ENOMEM; > goto out_regex_unlock; > } > > - if (reset) > - ftrace_filter_reset(hash); > if (buf && !ftrace_match_records(hash, buf, len)) { > ret = -EINVAL; > goto out_regex_unlock;
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