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Date: Sun, 30 Nov 2025 09:30:53 +0100
From: Greg KH <gregkh@linuxfoundation.org>
To: Lance Yang <lance.yang@linux.dev>
Cc: Aaron Tomlin <atomlin@atomlin.com>, linux-kernel@vger.kernel.org,
	mhiramat@kernel.org, akpm@linux-foundation.org,
	Petr Mladek <pmladek@suse.com>
Subject: Re: [PATCH] hung_task: Migrate hung_task_detect_count to sysfs
Message-ID: <2025113039-tycoon-glowworm-49f8@gregkh>
References: <20251129235159.1227977-1-atomlin@atomlin.com>
 <3e672e64-c03d-4129-ac13-13a45135b0f1@linux.dev>
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In-Reply-To: <3e672e64-c03d-4129-ac13-13a45135b0f1@linux.dev>

On Sun, Nov 30, 2025 at 01:43:51PM +0800, Lance Yang wrote:
> Hi Aaron,
> 
> Thanks for the patch.
> 
> On 2025/11/30 07:51, Aaron Tomlin wrote:
> > The hung_task_detect_count metric, which tracks the cumulative number of
> > tasks detected as hung since boot, is currently exposed via the legacy
> > /proc/sys/kernel/hung_task_detect_count sysctl file.
> > 
> > Migrate this metric to a read-only file in the /sys/kernel/ hierarchy:
> > /sys/kernel/hung_task_detect_count. The sysctl file is removed, and the
> > metric is now controlled by the CONFIG_SYSFS Kconfig option.
> 
> Emm, I don't think we should do this :)

I agree, because:

> Removing the sysctl file is going to break userspace tools that
> currently read it ...

We can't do that.

thanks,

greg k-h