linux-kernel - Re: [PATCH v2 2/2] clocksource: Use get_random_bytes() in clocksource_verify_choose

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Message-ID: <877c6d75tt.ffs@tglx>
Date: Wed, 29 Jan 2025 20:55:42 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: Waiman Long <llong@...hat.com>, Sebastian Andrzej Siewior
 <bigeasy@...utronix.de>
Cc: John Stultz <jstultz@...gle.com>, Stephen Boyd <sboyd@...nel.org>, Feng
 Tang <feng.tang@...el.com>, "Paul E. McKenney" <paulmck@...nel.org>, Clark
 Williams <clrkwllms@...nel.org>, Steven Rostedt <rostedt@...dmis.org>,
 linux-kernel@...r.kernel.org, linux-rt-devel@...ts.linux.dev
Subject: Re: [PATCH v2 2/2] clocksource: Use get_random_bytes() in
 clocksource_verify_choose_cpus()

On Wed, Jan 29 2025 at 12:03, Waiman Long wrote:
> On 1/29/25 11:34 AM, Sebastian Andrzej Siewior wrote:
>> But all this would avoid having to run with disabled preemption within
>> clocksource_verify_choose_cpus() while having the guarantees you need.
>
> I guess we will have to break clocksource_verify_choose_cpus() into 2 
> separate parts, one without preemption disabled and other one with 
> preemption disabled. I don't think it is a good idea to just use 
> migrate_disable() as we may get too much latency that can affect the 
> test result.
>
> I will send out a v3 patch to fix that.

I zap the topmost commit in timers/urgent then.