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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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9c23d824-f2c7-4f9a-ade2-e8dd3a0d30af@redhat.com> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 0B4B6C001B X-Stat-Signature: yawe8i4jfgwhqbfpgqc1ij8ck9sofgup X-HE-Tag: 1716387082-550918 X-HE-Meta: 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 OQdBhs7l X8SnHPIx3xT5gCNznXFf0v7Hte9SspsaNBTXhztz5iH0qnMHacGLsWRCH2C5cKQnvTIWP02r/c5K0BdI6jy+iBL2wry6EikM34AHExPOprWlxOH5aLLUWo4MuKrNaEpJfgAzg X-Bogosity: Ham, tests=bogofilter, spamicity=0.015647, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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.