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Shutemov" Cc: Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, "Rafael J. Wysocki" , Peter Zijlstra , Adrian Hunter , Kuppuswamy Sathyanarayanan , Elena Reshetova , Jun Nakajima , Rick Edgecombe , Tom Lendacky , "Kalra, Ashish" , Sean Christopherson , "Huang, Kai" , Baoquan He , kexec@lists.infradead.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, Tao Liu Subject: Re: [PATCHv10 03/18] cpu/hotplug: Add support for declaring CPU offlining not supported Message-ID: <20240423131722.GIZie04oK5g5f8Jftr@fat_crate.local> References: <20240409113010.465412-1-kirill.shutemov@linux.intel.com> <20240409113010.465412-4-kirill.shutemov@linux.intel.com> <20240418143709.GJZiEwFejGQY3jiwsp@fat_crate.local> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Fri, Apr 19, 2024 at 04:31:39PM +0300, Kirill A. Shutemov wrote: > Yes, it is one-off. I guess we could use READ_ONCE()/WRITE_ONCE() to > access the variable with the same result. I am not sure why it would be > better. Nah, and it is not even the first one-off: cpu_hotplug_disable/_enable() uses the same locking to update cpu_hotplug_disabled. I guess we need to update the comment over cpu_maps_update_begin(). I guess this is fine wrt big picture of the CPU hotplug universe. Lemme point tglx to it just in case. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette