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[35.189.240.49]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3502b8a78e8sm34775615f8f.61.2024.05.22.07.11.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 May 2024 07:11:20 -0700 (PDT) Date: Wed, 22 May 2024 14:11:16 +0000 From: Brendan Jackman To: David Hildenbrand Cc: Oscar Salvador , Andrew Morton , Mike Rapoport , Michal Hocko , Anshuman Khandual , Vlastimil Babka , Pavel Tatashin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] mm,memory_hotplug: {READ,WRITE}_ONCE unsynchronized zone data Message-ID: References: <20240521-mm-hotplug-sync-v1-0-6d53706c1ba8@google.com> <20240521-mm-hotplug-sync-v1-2-6d53706c1ba8@google.com> <9c23d824-f2c7-4f9a-ade2-e8dd3a0d30af@redhat.com> 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=us-ascii Content-Disposition: inline In-Reply-To: <9c23d824-f2c7-4f9a-ade2-e8dd3a0d30af@redhat.com> On Wed, May 22, 2024 at 04:05:12PM +0200, David Hildenbrand wrote: > On 21.05.24 14:57, Brendan Jackman wrote: > > + return zone->zone_start_pfn + READ_ONCE(zone->spanned_pages); > > It's weird to apply that logic only to spanned_pages, whereby zone_start_pfn > can (and will) similarly change when onlining/offlining memory. > Oh, yep. For some reason I had decided that zone_start_pfn was fixed but that is (actually very obviously) not true! Will take a closer look and extend v2 to cover that too, unless someone finds a reason this whole patch is nonsense. Thanks for the review.