linux-kernel - Re: [PATCHv4 14/14] x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method

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Message-ID: <20231222163420.4mu5kmznfmsave6k@box.shutemov.name>
Date: Fri, 22 Dec 2023 19:34:20 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: 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>,
	Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.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: [PATCHv4 14/14] x86/acpi: Add support for CPU offlining for ACPI
 MADT wakeup method

On Fri, Dec 15, 2023 at 09:29:13PM +0100, Thomas Gleixner wrote:
> So this waits and then does nothing if the wait fails. What's the point?
> 
> ...
> <SNIP 170 lines of pagetable muck>
> 
> Do we really need this specific hackery or is there some similar
> identity mapping muck which can be generalized?

I've addressed all your feedback, but this gave me pause. Looks like none
of kernel_ident_mapping_init() users frees memory on failure.

Is it okay to get this part as is and I will follow up with patchset that
fixes memory handling for all kernel_ident_mapping_init() users?

-- 
  Kiryl Shutsemau / Kirill A. Shutemov