From: Vincent Donnefort <vdonnefort@google.com>
To: rostedt@goodmis.org, mhiramat@kernel.org,
linux-trace-kernel@vger.kernel.org
Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com,
linux-kernel@vger.kernel.org,
Vincent Donnefort <vdonnefort@google.com>
Subject: [PATCH v1 2/9] ring-buffer: Drop cpus_read_lock() from ring_buffer_poll_remote()
Date: Thu, 12 Nov 2026 14:14:33 +0000 [thread overview]
Message-ID: <20261112141440.3050124-3-vdonnefort@google.com> (raw)
In-Reply-To: <20261112141440.3050124-1-vdonnefort@google.com>
ring_buffer_poll_remote() holds cpus_read_lock() while walking
buffer->cpumask. Ring buffers are never freed on CPU hotunplug, and
trace_rb_cpu_prepare() already orders buffer->buffers with the cpumask
update (with rb_cpu_sync()). Drop cpus_read_lock() as it is
unnecessary.
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
---
kernel/trace/ring_buffer.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index bd8126f6353b..32d3c47dbdf0 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -6918,8 +6918,6 @@ int ring_buffer_poll_remote(struct trace_buffer *buffer, int cpu)
return 0;
}
- guard(cpus_read_lock)();
-
/*
* Make sure all the ring buffers are up to date before we start reading
* them.
--
2.56.0.567.gdb80ae8cd5-goog
next prev parent reply other threads:[~2026-11-12 14:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-12 14:14 [PATCH v1 0/9] ring-buffer: Enable Clang context analysis Vincent Donnefort
2026-11-12 14:14 ` [PATCH v1 1/9] ring-buffer: Always read buffer->buffers after testing the cpumask Vincent Donnefort
2026-11-12 14:22 ` sashiko-bot
2026-11-12 14:14 ` Vincent Donnefort [this message]
2026-11-12 14:14 ` [PATCH v1 3/9] ring-buffer: Hold buffer->mutex in trace_rb_cpu_prepare() Vincent Donnefort
2026-11-12 14:14 ` [PATCH v1 4/9] tracing: Cache ring_buffer_max_event_size() for trace_marker Vincent Donnefort
2026-11-12 14:25 ` sashiko-bot
2026-11-12 14:14 ` [PATCH v1 5/9] ring-buffer: Validate event length against rb_page_capacity() Vincent Donnefort
2026-11-12 14:14 ` [PATCH v1 6/9] ring-buffer: Introduce rb_start_write() and rb_end_write() Vincent Donnefort
2026-11-12 14:14 ` [PATCH v1 7/9] ring-buffer: Avoid reading buffer::subbuf_order on the write path Vincent Donnefort
2026-11-12 14:14 ` [PATCH v1 8/9] ring-buffer: Enable context analysis Vincent Donnefort
2026-11-12 14:28 ` sashiko-bot
2026-11-12 14:14 ` [PATCH v1 9/9] ring-buffer: Annotate subbuf_order with __guarded_by(&mutex) Vincent Donnefort
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