From: Jens Axboe <axboe@kernel.dk>
To: Wander Lairson Costa <wander@redhat.com>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
"open list:BLOCK LAYER" <linux-block@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [PATCH v5 1/1] blktrace: switch trace spinlock to a raw spinlock
Date: Mon, 20 Dec 2021 12:38:22 -0700 [thread overview]
Message-ID: <8340efc7-f922-fb8c-772c-de72cefe3470@kernel.dk> (raw)
In-Reply-To: <20211220192827.38297-1-wander@redhat.com>
On 12/20/21 12:28 PM, Wander Lairson Costa wrote:
> The running_trace_lock protects running_trace_list and is acquired
> within the tracepoint which implies disabled preemption. The spinlock_t
> typed lock can not be acquired with disabled preemption on PREEMPT_RT
> because it becomes a sleeping lock.
> The runtime of the tracepoint depends on the number of entries in
> running_trace_list and has no limit. The blk-tracer is considered debug
> code and higher latencies here are okay.
You didn't put a changelog in here. Was this one actually compiled? Was
it runtime tested?
--
Jens Axboe
next prev parent reply other threads:[~2021-12-20 19:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-20 19:28 [PATCH v5 1/1] blktrace: switch trace spinlock to a raw spinlock Wander Lairson Costa
2021-12-20 19:38 ` Jens Axboe [this message]
2021-12-20 19:49 ` Wander Costa
2021-12-20 20:24 ` Jens Axboe
2021-12-20 20:34 ` Wander Costa
2021-12-20 20:37 ` Jens Axboe
2021-12-20 20:43 ` Wander Costa
2021-12-20 20:49 ` Jens Axboe
2021-12-20 23:30 ` Steven Rostedt
2021-12-20 23:45 ` Jens Axboe
2021-12-20 20:50 ` Jens Axboe
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