linux-kernel - Re: [PATCHv6 16/16] x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method

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Message-ID: <vfk7v6ywaclyydshucnnuvsyg6e6sntyzimgqgjc7ye77z2ukr@lk4e3wz4ap3y>
Date: Sat, 27 Jan 2024 21:35:41 +0200
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: 
	Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, 
	Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	"Rafael J. Wysocki" <rafael@...nel.org>, Peter Zijlstra <peterz@...radead.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Elena Reshetova <elena.reshetova@...el.com>, 
	Jun Nakajima <jun.nakajima@...el.com>, Rick Edgecombe <rick.p.edgecombe@...el.com>, 
	Tom Lendacky <thomas.lendacky@....com>, "Kalra, Ashish" <ashish.kalra@....com>, 
	Sean Christopherson <seanjc@...gle.com>, "Huang, Kai" <kai.huang@...el.com>, Baoquan He <bhe@...hat.com>, 
	kexec@...ts.infradead.org, linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv6 16/16] x86/acpi: Add support for CPU offlining for ACPI
 MADT wakeup method

On Fri, Jan 26, 2024 at 12:03:14PM -0800, Kuppuswamy Sathyanarayanan wrote:
> > +	/* Don't wait longer than a second. */
> > +	timeout = USEC_PER_SEC;
> > +	while (READ_ONCE(acpi_mp_wake_mailbox->command) && --timeout)
> > +		udelay(1);
> > +
> > +	if (!timeout)
> Nit: IMO, since you are dumping failure error message (not timeout
> message), you can use non zero acpi_mp_wake_mailbox->command
> check. But it is up to you.

I think my version is pretty idiomatic. The same pattern used in other
places. For instance, test_nmi_ipi().
-- 
  Kiryl Shutsemau / Kirill A. Shutemov