lkml.org 
[lkml]   [2015]   [Dec]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ftrace: Remove use of control list and ops
On Tue, Dec 01, 2015 at 09:55:54AM -0500, Steven Rostedt wrote:
> On Tue, 1 Dec 2015 14:42:36 +0100
> Jiri Olsa <jolsa@redhat.com> wrote:
>
> > On Mon, Nov 30, 2015 at 05:36:40PM -0500, Steven Rostedt wrote:
> > >
> > > [ Jiri, can you take a look at this. You can also apply it on top of my
> > > branch ftrace/core, and run any specific tests. I just need to nuke
> > > that control structure for further updates with ftrace. ]
> > >
> > >
> > > Currently perf has its own list function within the ftrace infrastructure
> > > that seems to be used only to allow for it to have per-cpu disabling as well
> > > as a check to make sure that it's not called while RCU is not watching. It
> > > uses something called the "control_ops" which is used to iterate over ops
> > > under it with the control_list_func().
> > >
> > > The problem is that this control_ops and control_list_func unnecessarily
> > > complicates the code. By replacing FTRACE_OPS_FL_CONTROL with two new flags
> > > (FTRACE_OPS_FL_RCU and FTRACE_OPS_FL_PER_CPU) we can remove all the code
> > > that is special with the control ops and add the needed checks within the
> > > generic ftrace_list_func().
> >
> > hum,
> > do we need also change for the trampoline, something like below?
> >
> > I needed attached patch to get the perf ftrace:function
> > event work properly..
>
> Hmm, I thought that I forced the list function when RCU or PER_CPU
> was set. Oh wait. I have CONFIG_PREEMPT set, which will change the
> logic slightly. I'm guessing you have PREEMPT_VOLUNTARY set. I'll try
> that out.

yep, but the trampoline has separate code path
to set the ops func

jirka


\
 
 \ /
  Last update: 2015-12-01 17:21    [W:0.048 / U:0.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site