From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
stable@vger.kernel.org
Subject: [for-next][PATCH 08/15] tracing: Wake up waiters when tracing is disabled
Date: Thu, 29 Sep 2022 18:55:50 -0400 [thread overview]
Message-ID: <20220929225637.791264178@goodmis.org> (raw)
In-Reply-To: 20220929225542.784716766@goodmis.org
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
When tracing is disabled, there's no reason that waiters should stay
waiting, wake them up, otherwise tasks get stuck when they should be
flushing the buffers.
Cc: stable@vger.kernel.org
Fixes: e30f53aad2202 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/trace.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 58afc83afc9d..bb5597c6bfc1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8334,6 +8334,10 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
if (ret)
goto out;
+ /* No need to wait after waking up when tracing is off */
+ if (!tracer_tracing_is_on(iter->tr))
+ goto out;
+
/* Make sure we see the new wait_index */
smp_rmb();
if (wait_index != iter->wait_index)
@@ -9065,6 +9069,8 @@ rb_simple_write(struct file *filp, const char __user *ubuf,
tracer_tracing_off(tr);
if (tr->current_trace->stop)
tr->current_trace->stop(tr);
+ /* Wake up any waiters */
+ ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);
}
mutex_unlock(&trace_types_lock);
}
--
2.35.1
prev parent reply other threads:[~2022-09-29 22:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220929225542.784716766@goodmis.org>
2022-09-29 22:55 ` [for-next][PATCH 02/15] ring-buffer: Allow splice to read previous partially read pages Steven Rostedt
2022-09-29 22:55 ` [for-next][PATCH 03/15] ring-buffer: Have the shortest_full queue be the shortest not longest Steven Rostedt
2022-09-29 22:55 ` [for-next][PATCH 04/15] ring-buffer: Check pending waiters when doing wake ups as well Steven Rostedt
2022-09-29 22:55 ` [for-next][PATCH 05/15] ring-buffer: Add ring_buffer_wake_waiters() Steven Rostedt
2022-09-29 22:55 ` [for-next][PATCH 06/15] tracing: Wake up ring buffer waiters on closing of the file Steven Rostedt
2022-09-29 22:55 ` [for-next][PATCH 07/15] tracing: Add ioctl() to force ring buffer waiters to wake up Steven Rostedt
2022-09-29 22:55 ` Steven Rostedt [this message]
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