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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	paulmck <paulmck@kernel.org>, Stefan Metzmacher <metze@samba.org>,
	stable <stable@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] Fix: tracepoint: static call function vs data state mismatch (v2)
Date: Thu, 5 Aug 2021 15:42:54 -0400 (EDT)	[thread overview]
Message-ID: <1847120259.7313.1628192574061.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <20210805153817.1c82dcc6@oasis.local.home>

----- On Aug 5, 2021, at 3:38 PM, rostedt rostedt@goodmis.org wrote:

> On Thu, 5 Aug 2021 15:15:43 -0400 (EDT)
> Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:
> 
>> ----- On Aug 5, 2021, at 2:56 PM, rostedt rostedt@goodmis.org wrote:
>> 
>> > Note, there shouldn't be a "(v2)" outside the "[PATCH ]" part.
>> > Otherwise it gets added into the git commit during "git am".
>> 
>> Out of curiosity, do you know any way to annotate my local commits to have the
>> [PATCH v2] tag automatically generated by git send-email ?
> 
> I pass -v2 to git send-email, and it adds the v2 for me.

OK, so you version the entire patch series in one go. It makes sense.

> 
>> > This is a big enough regression, I'll even add a Fixes tag to the next
>> > patch on the final sha1 of this patch! Such that this patch won't be
>> > backported without the next patch.
>> 
>> This makes sense. I still wanted to keep the two patches separate so we would
>> introduce the (slow) state machine in the first patch, and optimize for
>> speed in the second. My intent is to facilitate of small logical changes,
>> and make bisection more precise in the future if we introduce an issue
>> here.
> 
> I agree which is why I didn't ask you to fold them. The logic in this
> code was a big enough change, where I agree it should be kept separate.
> Unfortunately, it caused a huge performance regression :-(, but at the
> same time, fixed a correctness issue, which Thomas always says that
> correctness trumps performance.
> 
> But the compromise is to add a Fixes tag to the next patch and document
> why they are separated, but still required to act as "one". I'll add
> that commentary.

Perfect, thanks!

Mathieu

> 
> -- Steve
> 
>> 
>> Calling out more clearly how slow things become with this patch is indeed
>> important.
>> 
>> >   
>> >> 

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

  reply	other threads:[~2021-08-05 19:42 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-05 13:27 [PATCH 0/3] tracepoint static call fixes Mathieu Desnoyers
2021-08-05 13:27 ` [PATCH 1/3] Fix: tracepoint: static call: compare data on transition from 2->1 callees Mathieu Desnoyers
2021-08-05 17:07   ` Steven Rostedt
2021-08-05 17:57     ` Mathieu Desnoyers
2021-08-05 13:27 ` [PATCH 2/3] Fix: tracepoint: static call function vs data state mismatch (v2) Mathieu Desnoyers
2021-08-05 18:56   ` Steven Rostedt
2021-08-05 19:15     ` Mathieu Desnoyers
2021-08-05 19:38       ` Steven Rostedt
2021-08-05 19:42         ` Mathieu Desnoyers [this message]
2021-08-05 13:27 ` [PATCH 3/3] Fix: tracepoint: rcu get state and cond sync for static call updates (v2) Mathieu Desnoyers
2021-08-05 19:12   ` Steven Rostedt
2021-08-05 19:29     ` [PATCH v3 1/1] Fix: tracepoint: rcu get state and cond sync for static call updates Mathieu Desnoyers

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