Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 24 Aug 2021 10:31:16 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Dave Jones <davej@codemonkey.org.uk>,
        Linux Kernel <linux-kernel@vger.kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: 5.14-rc breaks iotop swap io monitoring.
Message-ID: <YSSuVO47ieWDfWMQ@hirez.programming.kicks-ass.net>
References: <20210824031648.GA2725@codemonkey.org.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20210824031648.GA2725@codemonkey.org.uk>
Precedence: bulk

On Mon, Aug 23, 2021 at 11:16:48PM -0400, Dave Jones wrote:
> I just noticed that in 5.14-rc running iotop, it complains on startup
> that "CONFIG_TASK_DELAY_ACCT not enabled in kernel, cannot determine
> SWAPIN and IO %" and sure enough a bunch of columns show up as
> 'unavailable'.
> 
> My suspicion is this commit, which I've not confirmed yet as it doesn't
> cleanly revert.  I'll poke at it some more in the morning, but figured
> I'd bring it up sans-evidence in the hope that I'll wake up to someone
> having an Ah-ha moment.

If you need DELAYACCT I'm thinking:

  e4042ad49235 ("delayacct: Default disabled")

and

  0cd7c741f01d ("delayacct: Add sysctl to enable at runtime")

might be more relevant..