linux-kernel - [RFC][PATCH 08/11] ring-buffer: Do not disable recording when there is an iterator

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Date:   Tue, 17 Mar 2020 17:32:30 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     linux-kernel@...r.kernel.org
Cc:     Ingo Molnar <mingo@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Alexei Starovoitov <alexei.starovoitov@...il.com>,
        Peter Wu <peter@...ensteyn.nl>,
        Jonathan Corbet <corbet@....net>,
        Tom Zanussi <zanussi@...nel.org>
Subject: [RFC][PATCH 08/11] ring-buffer: Do not disable recording when there is an iterator

From: "Steven Rostedt (VMware)" <rostedt@...dmis.org>

Now that the iterator can handle a concurrent writer, do not disable writing
to the ring buffer when there is an iterator present.

Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
---
 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 5979327254f9..8bafba674ec0 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -4295,7 +4295,6 @@ ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags)
 	iter->cpu_buffer = cpu_buffer;
 
 	atomic_inc(&buffer->resize_disabled);
-	atomic_inc(&cpu_buffer->record_disabled);
 
 	return iter;
 }
@@ -4368,7 +4367,6 @@ ring_buffer_read_finish(struct ring_buffer_iter *iter)
 	rb_check_pages(cpu_buffer);
 	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
-	atomic_dec(&cpu_buffer->record_disabled);
 	atomic_dec(&cpu_buffer->buffer->resize_disabled);
 	kfree(iter->event);
 	kfree(iter);
-- 
2.25.1