From: Martin Weiss <martin.githubacc@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Martin Weiss <Martin.weiss2410@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-trace-kernel@vger.kernel.org
Subject: [PATCH] trace_branch: use per-cpu counters for correct/incorrect stats
Date: Mon, 29 Jun 2026 16:58:38 +0700 [thread overview]
Message-ID: <20260629095838.601926-1-Martin.weiss2410@gmail.com> (raw)
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 <Martin.weiss2410@gmail.com>
---
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);
user_access_restore(flags);
}
--
2.54.0
next reply other threads:[~2026-06-29 9:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-29 9:58 Martin Weiss [this message]
2026-06-29 10:47 ` [PATCH] trace_branch: use per-cpu counters for correct/incorrect stats Steven Rostedt
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