Messages in this thread Patch in this message | | | Date | Tue, 4 Dec 2018 12:26:27 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH 3/3] arm64: ftrace: add cond_resched() to func ftrace_make_(call|nop) |
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On Tue, 4 Dec 2018 11:12:43 +0000 Will Deacon <will.deacon@arm.com> wrote:
> > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > > index 8ef9fc226037..42e89397778b 100644 > > --- a/kernel/trace/ftrace.c > > +++ b/kernel/trace/ftrace.c > > @@ -2393,11 +2393,14 @@ void __weak ftrace_replace_code(int enable) > > { > > struct dyn_ftrace *rec; > > struct ftrace_page *pg; > > + bool schedulable; > > int failed; > > > > if (unlikely(ftrace_disabled)) > > return; > > > > + schedulable = !irqs_disabled() & !preempt_count(); > > Looks suspiciously like a bitwise preemptible() to me!
Ah, thanks. Yeah, that should have been &&. But what did you expect. I didn't even compile this ;-)
> > > + > > do_for_each_ftrace_rec(pg, rec) { > > > > if (rec->flags & FTRACE_FL_DISABLED) > > @@ -2409,6 +2412,8 @@ void __weak ftrace_replace_code(int enable) > > /* Stop processing */ > > return; > > } > > + if (schedulable) > > + cond_resched(); > > } while_for_each_ftrace_rec(); > > } > > If this solves the problem in core code, them I'm all for it. Otherwise, I > was thinking of rolling our own ftrace_replace_code() for arm64, but that's > going to involve a fair amount of duplication. >
If it does, then I'll add it. Or take a patch for it ;-)
My main concern is that this can be called from non schedulable context.
-- Steve
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