From: Peter Zijlstra <peterz@infradead.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Qais Yousef <qais.yousef@arm.com>, Ingo Molnar <mingo@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org,
Pavankumar Kondeti <pkondeti@codeaurora.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Uwe Kleine-Konig <u.kleine-koenig@pengutronix.de>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Quentin Perret <quentin.perret@arm.com>
Subject: Re: [PATCH v3 0/6] sched: Add new tracepoints required for EAS testing
Date: Wed, 5 Jun 2019 09:22:27 +0200 [thread overview]
Message-ID: <20190605072227.GI3419@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190605061748.GA20661@infradead.org>
On Tue, Jun 04, 2019 at 11:17:48PM -0700, Christoph Hellwig wrote:
> > The following patches add the bare minimum tracepoints required to perform EAS
> > testing in Lisa[1].
>
> What is EAS? Whhy is "Lisa" not part of the patch submission?
> submission.
>
> > It is done in this way because adding new TRACE_EVENTS() is no longer accepted
> > AFAIU.
>
> Huh? We keep adding trace events all the time. And they actually
> are useful because they are testable.
They also form an implicit API/ABI with userspace, and I've been bitten
by that crap before. No more tracepoints. IIRC viro is also not having
tracepoints in the vfs.
> This series on the other hand adds exports not used in tree, which is
> a big no-go.
I much prefer a few unused exports that expose data in a controlled
fashion than commit to an implicit ABI through tracepoints. By keeping
it all in kernel, we're punting to the no-in-kernel-ABI rule.
Basically nobody gives a crap if we break (out-of-tree) modules, but the
moment we break something userspace we're fscked.
next prev parent reply other threads:[~2019-06-05 7:22 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-04 11:14 [PATCH v3 0/6] sched: Add new tracepoints required for EAS testing Qais Yousef
2019-06-04 11:14 ` [PATCH v3 1/6] sched: autogroup: Make autogroup_path() always available Qais Yousef
2019-06-25 8:24 ` [tip:sched/core] sched/autogroup: " tip-bot for Qais Yousef
2019-06-04 11:14 ` [PATCH v3 2/6] sched: add a new sched_trace_*() helper functions Qais Yousef
2019-06-25 8:25 ` [tip:sched/core] sched/debug: Add " tip-bot for Qais Yousef
2019-06-04 11:14 ` [PATCH v3 3/6] sched: Add new tracepoints to track pelt at rq level Qais Yousef
2019-06-25 8:26 ` [tip:sched/core] sched/debug: Add new tracepoints to track PELT " tip-bot for Qais Yousef
2019-06-04 11:14 ` [PATCH v3 4/6] sched: Add new tracepoint to track pelt at se level Qais Yousef
2019-06-25 8:27 ` [tip:sched/core] sched/debug: Add new tracepoint to track PELT " tip-bot for Qais Yousef
2019-06-04 11:14 ` [PATCH v3 5/6] sched: Add sched_overutilized tracepoint Qais Yousef
2019-06-17 15:50 ` Peter Zijlstra
2019-06-17 16:31 ` Qais Yousef
2019-06-25 8:27 ` [tip:sched/core] sched/debug: " tip-bot for Qais Yousef
2019-06-04 11:14 ` [PATCH v3 6/6] sched: export the newly added tracepoints Qais Yousef
2019-06-25 8:28 ` [tip:sched/core] sched/debug: Export " tip-bot for Qais Yousef
2019-06-05 6:17 ` [PATCH v3 0/6] sched: Add new tracepoints required for EAS testing Christoph Hellwig
2019-06-05 7:22 ` Peter Zijlstra [this message]
2019-06-05 22:33 ` Qais Yousef
2019-06-17 12:51 ` Qais Yousef
2019-06-17 15:55 ` Peter Zijlstra
2019-06-17 16:22 ` Qais Yousef
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