On Mon, 29 Jun 2026 16:58:38 +0700 Martin Weiss <[email protected]> wrote:
> Replace per-task counters with per-cpu increments to avoid race > conditions in the branch profiler fast path. > > Fixes FIXME about atomicity. > > Signed-off-by: Martin Weiss <[email protected]> > --- > kernel/trace/trace_branch.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c > index d8e97ad798f0..960bcb3d7dbf 100644 > --- a/kernel/trace/trace_branch.c > +++ b/kernel/trace/trace_branch.c > @@ -213,11 +213,11 @@ void ftrace_likely_update(struct ftrace_likely_data *f, > int val, > */ > trace_likely_condition(f, val, expect); > > - /* FIXME: Make this atomic! */ > + /* use per-cpu counters to avoid contention */ > if (val == expect) > - f->data.correct++; > + this_cpu_inc(f->data.correct); > else > - f->data.incorrect++; > + this_cpu_inc(f->data.incorrect); I don't think this does what you think it does. Did you even test this? I'm guessing it would blow up in some fantastic ways. NAK. -- Steve > > user_access_restore(flags); > }
